Effect of zinc supplementation between 1 and 6 mo of life on growth and morbidity of Bangladeshi infants in urban slums

Determinants of pneumonia among under-five children at Hiwot Fana specialized hospital, Eastern Ethiopia: unmatched case-control study

BACKGROUND

Globally, pneumonia is a serious public health issue. Clear evidence is necessary for the early detection and treatment of pneumonia's causes. Yet, there is limited data on this issue in the current study area. Thus, this study aimed to pinpoint the determinants of pneumonia among under-five children at Hiwot Fana Specialized Hospital, Eastern Ethiopia.

METHODS

A hospital-based unmatched case-control study was conducted among a sample of 348 (116 cases and 232 controls) children at Hiwot Fana Specialized Hospital from October 1 to November 30, 2022. A consecutive sampling technique was employed, and data were collected with a pre-tested interviewer-administered questionnaire. The data was entered into Epi-Data version 3.1 and analyzed using SPSS version 25 software. Bivariate and multivariate binary logistic regression analyses were fitted. Variables with a 95% confidence interval having a p-value < 0.05 were considered statistically significant.

RESULTS

An overall total of 347 (115 cases and 232 controls) among under-five children was included in this study. Factors such as hand washing before child feeding [AOR: 3.11 (1.74-5.57)], birth to 6 months breastfeeding [AOR: 2.76 (1.35-5.25)], zinc supplementation [AOR: 2.5 (1.33-4.40)], diarrhea in the last 2 weeks [AOR: 4.7 (2.64-8.33)], and Upper Respiratory Tract Infections in the last 2 weeks [AOR: 5.46 (3.21-10.92)] were found to be determinants of pneumonia.

CONCLUSIONS

This study pointed out that the under-five pneumonia was relatively large. Factors such as hand washing before child feeding, birth to 6 months of breastfeeding, zinc supplementation of the child, diarrhea in the last 2 weeks, and Upper Respiratory Tract Infections in the last 2 weeks were determinants of under-five pneumonia. In this study, the primary risk factors for pneumonia may be preventable with no or minimal cost. Therefore, we advise suitable and sufficient health education addressing the prevention and management of pneumonia.

Zinc supplementation for preventing mortality, morbidity, and growth failure in children aged 6 months to 12 years

BACKGROUND

Zinc deficiency is prevalent in low- and middle-income countries, and is considered a significant risk factor for morbidity, mortality, and linear growth failure. The effectiveness of preventive zinc supplementation in reducing prevalence of zinc deficiency needs to be assessed.

OBJECTIVES

To assess the effects of zinc supplementation for preventing mortality and morbidity, and for promoting growth, in children aged 6 months to 12 years.

SEARCH METHODS

A previous version of this review was published in 2014. In this update, we searched CENTRAL, MEDLINE, Embase, five other databases, and one trials register up to February 2022, together with reference checking and contact with study authors to identify additional studies.

SELECTION CRITERIA

Randomized controlled trials (RCTs) of preventive zinc supplementation in children aged 6 months to 12 years compared with no intervention, a placebo, or a waiting list control. We excluded hospitalized children and children with chronic diseases or conditions. We excluded food fortification or intake, sprinkles, and therapeutic interventions.

DATA COLLECTION AND ANALYSIS

Two review authors screened studies, extracted data, and assessed the risk of bias. We contacted study authors for missing information and used GRADE to assess the certainty of evidence. The primary outcomes of this review were all-cause mortality; and cause-specific mortality, due to all-cause diarrhea, lower respiratory tract infection (LRTI, including pneumonia), and malaria. We also collected information on a number of secondary outcomes, such as those related to diarrhea and LRTI morbidity, growth outcomes and serum levels of micronutrients, and adverse events.

MAIN RESULTS

We included 16 new studies in this review, resulting in a total of 96 RCTs with 219,584 eligible participants. The included studies were conducted in 34 countries; 87 of them in low- or middle-income countries. Most of the children included in this review were under five years of age. The intervention was delivered most commonly in the form of syrup as zinc sulfate, and the most common dose was between 10 mg and 15 mg daily. The median duration of follow-up was 26 weeks. We did not consider that the evidence for the key analyses of morbidity and mortality outcomes was affected by risk of bias. High-certainty evidence showed little to no difference in all-cause mortality with preventive zinc supplementation compared to no zinc (risk ratio (RR) 0.93, 95% confidence interval (CI) 0.84 to 1.03; 16 studies, 17 comparisons, 143,474 participants). Moderate-certainty evidence showed that preventive zinc supplementation compared to no zinc likely results in little to no difference in mortality due to all-cause diarrhea (RR 0.95, 95% CI 0.69 to 1.31; 4 studies, 132,321 participants); but probably reduces mortality due to LRTI (RR 0.86, 95% CI 0.64 to 1.15; 3 studies, 132,063 participants) and mortality due to malaria (RR 0.90, 95% CI 0.77 to 1.06; 2 studies, 42,818 participants); however, the confidence intervals around the summary estimates for these outcomes were wide, and we could not rule out a possibility of increased risk of mortality. Preventive zinc supplementation likely reduces the incidence of all-cause diarrhea (RR 0.91, 95% CI 0.90 to 0.93; 39 studies, 19,468 participants; moderate-certainty evidence) but results in little to no difference in morbidity due to LRTI (RR 1.01, 95% CI 0.95 to 1.08; 19 studies, 10,555 participants; high-certainty evidence) compared to no zinc. There was moderate-certainty evidence that preventive zinc supplementation likely leads to a slight increase in height (standardized mean difference (SMD) 0.12, 95% CI 0.09 to 0.14; 74 studies, 20,720 participants). Zinc supplementation was associated with an increase in the number of participants with at least one vomiting episode (RR 1.29, 95% CI 1.14 to 1.46; 5 studies, 35,192 participants; high-certainty evidence). We report a number of other outcomes, including the effect of zinc supplementation on weight and serum markers such as zinc, hemoglobin, iron, copper, etc. We also performed a number of subgroup analyses and there was a consistent finding for a number of outcomes that co-supplementation of zinc with iron decreased the beneficial effect of zinc.

AUTHORS' CONCLUSIONS

Even though we included 16 new studies in this update, the overall conclusions of the review remain unchanged. Zinc supplementation might help prevent episodes of diarrhea and improve growth slightly, particularly in children aged 6 months to 12 years of age. The benefits of preventive zinc supplementation may outweigh the harms in regions where the risk of zinc deficiency is relatively high.

Basis for changes in the disease burden estimates related to vitamin A and zinc deficiencies in the 2017 and 2019 Global Burden of Disease Studies

BACKGROUND

The Global Burden of Disease (GBD) Study provides estimates of death and disability from eighty-seven risk factors, including some micronutrient deficiencies.

OBJECTIVES

To review methodological changes that led to large differences in the disease burden estimates for vitamin A and Zn deficiencies between the GBD 2017 and 2019 Studies.

METHODS

GBD publications were reviewed; additional information was provided by GBD researchers.

RESULTS

Vitamin A deficiency prevalence is based on plasma retinol concentration, whereas the estimate for Zn deficiency prevalence uses dietary adequacy as a proxy. The estimated global prevalence of vitamin A deficiency for children aged 1-4 years in the year 2017 decreased from 0·20 (95 % CI 0·17, 0·24) in GBD 2017 to 0·16 (95 % CI 0·15, 0·19) in GBD 2019, while the global prevalence of Zn deficiency did not change between the two studies (0·09 (95 % CI 0·04, 0·17) and 0·09 (95 % CI 0·03, 0·18)). New to 2019 was that meta-analyses were performed using Meta Regression - Bayesian, Regularized, Trimmed, a method developed for GBD. Due to this and multiple other methodological changes, the estimated number of deaths due to vitamin A deficiency dropped from 233 000 (179 000-294 000) to 24 000 (3000-50 000) from GBD 2017 to 2019, and for Zn deficiency from 29 000 (1000-77 000) to 2800 (700-6500), respectively.

CONCLUSION

The changes in the estimated disease burdens due to vitamin A and Zn deficiencies in the GBD reports from 2017 to 2019 are due primarily to changes in the analytical methods employed, so may not represent true changes in disease burden. Additional effort is needed to validate these results.

Challenges for Estimating the Global Prevalence of Micronutrient Deficiencies and Related Disease Burden: A Case Study of the Global Burden of Disease Study

Information on the prevalence of micronutrient deficiencies is needed to determine related disease burden; underpin evidence-based advocacy; and design, deliver, and monitor safe, effective interventions. Assessing the global prevalence of deficiency requires a valid micronutrient status biomarker with an appropriate cutoff to define deficiency and relevant data from representative surveys across multiple locations and years. The Global Burden of Disease Study includes prevalence estimates for iodine, iron, zinc, and vitamin A deficiencies, for which recommended biomarkers and appropriate deficiency cutoffs exist. Because representative survey data are lacking, only retinol concentration is used to model vitamin A deficiency, and proxy indicators are used for the other micronutrients (goiter for iodine, hemoglobin for iron, and dietary food adequacy for zinc). Because of data limitations, complex statistical modeling is required to produce current estimates, relying on assumptions and proxies that likely understate the extent of micronutrient deficiencies and the consequent global health burden.

Macro- and Trace-Element Intake from Human Milk in Australian Infants: Inadequacy with Respect to National Recommendations

Longitudinal variations of macro- and trace elements in human milk (HM) are not well characterised, and therefore, the recommendations for intake for Australian infants require more evidence to ensure accuracy. We aimed to investigate the longitudinal variation of HM macro- and trace-element concentrations (1-12 months) and infant intake (1-6 months) and to investigate the relationships between intake and infant growth parameters at 3 and 6 months, and determine if intake was sufficient when compared to national guidelines. HM samples were collected monthly for the first 6 months and then at 9 and 12 months postpartum from mother-infant dyads (n = 83). Test-weighing was used to determine the volume of HM consumed daily. Element concentrations (Na, Ca, K, Mg, P, I, Se, Zn, Cu, Mn, Mo, and Fe) were measured using ICP-MS, and intake was calculated using the measured concentrations and the volume of HM consumed. The average intake of HM was 776.3 ± 24.0 mL for the infants. Changes in concentration from months 1 to 12 postpartum were observed for all the measured micronutrients (all p < 0.05). The calculated intakes of all the macro- and trace elements showed that 0% to 82% of infants met the current adequate recommendations at varying periods of lactation. The calculated macro- and trace-element intakes were below the adequate intake recommendations, suggesting that they are not reflective of healthy infant requirements. These findings suggest the need for larger studies using sensitive analytical techniques and the revision of current recommendations for breastfed infants.

Daily and within-feed variation of macro- and trace-element concentrations in human milk and implications for sampling

BACKGROUND

Daily variations of macro- and trace-elements in human milk (HM) are not well characterised and sampling protocols are highly variable between studies.

OBJECTIVES

To investigate diurnal and within-feed variation of HM macro- and trace-elements using pre- and post- feed concentrations and to compare infant intake estimates using limited samples with measured 24-hour intake.

METHODS

HM Samples were collected pre- and post- every feed in a 24-hour period from 11 mother-infant dyads. Test-weighing was used to determine the volume of HM consumed in each feed. For macro- and trace-elements within-feed and daily variation was measured. Intake estimated from a morning pre-feed sample was compared to the measured milk intake calculated from every feed over 24-hours. Macro- and trace-elements concentrations were measured using ICP-MS. Linear mixed modelling was used for statistical analysis.

RESULTS

Average intake of HM was 737 ± 63 mL for infants aged 1-6 months and 508 ± 50 for infants aged 6-12 months. Pre- and post-feed HM variation was found for phosphorus, calcium, manganese, iron, copper, zinc, selenium, molybdenum, and iodine (p < 0.05). Variation across 24 h was found for magnesium, phosphorus, potassium, manganese, iron, and selenium (p < 0.05). Estimated intake using morning, pre-feed samples resulted in significantly lower intake when compared to measured milk intake for iron, phosphorus, selenium, and manganese (p < 0.05).

CONCLUSION

Standardised sampling protocols using large sample volumes and multiple collections over 24-hours provide a calculated intake that is more reflective of actual infant HM macro- and trace-elements intake.

The Role of Micronutrients in Support of the Immune Response against Viral Infections

Viral infections are a leading cause of morbidity and mortality worldwide, and the importance of public health practices including handwashing and vaccinations in reducing their spread is well established. Furthermore, it is well known that proper nutrition can help support optimal immune function, reducing the impact of infections. Several vitamins and trace elements play an important role in supporting the cells of the immune system, thus increasing the resistance to infections. Other nutrients, such as omega-3 fatty acids, help sustain optimal function of the immune system. The main aim of this manuscript is to discuss of the potential role of micronutrients supplementation in supporting immunity, particularly against respiratory virus infections. Literature analysis showed that in vitro and observational studies, and clinical trials, highlight the important role of vitamins A, C, and D, omega-3 fatty acids, and zinc in modulating the immune response. Supplementation with vitamins, omega 3 fatty acids and zinc appears to be a safe and low-cost way to support optimal function of the immune system, with the potential to reduce the risk and consequences of infection, including viral respiratory infections. Supplementation should be in addition to a healthy diet and fall within recommended upper safety limits set by scientific expert bodies. Therefore, implementing an optimal nutrition, with micronutrients and omega-3 fatty acids supplementation, might be a cost-effective, underestimated strategy to help reduce the burden of infectious diseases worldwide, including coronavirus disease 2019 (COVID-19).

Interventions to improve linear growth during exclusive breastfeeding life-stage for children aged 0-6 months living in low- and middle-income countries: a systematic review with network and pairwise meta-analyses

Background: Exclusive breastfeeding (EBF) during the first six months of life is critical for child's linear growth. While there is strong evidence in favor of EBF, the evidence with regards to other interventions for linear growth is unclear. We evaluated intervention domains of micronutrients, food supplements, deworming, maternal education, water sanitation and hygiene (WASH), and kangaroo care, for their comparative effectiveness on linear growth. Methods: For this review, we searched for randomized clinical trials (RCTs) of the interventions provided to infants aged 0-6 months and/or their breastfeeding mothers in low- and middle-income countries reporting on length-for-age z-score (LAZ), stunting, length, and head circumference. We searched for reports published until September 17 th, 2019 and hand-searched bibliographies of existing reviews. For LAZ and stunting, we used network meta-analysis (NMA) to compare the effects of all interventions except for kangaroo care, where we used pairwise meta-analysis to compare its effects versus standard-of-care. For length and head circumference, we qualitatively summarized our findings. Results: We found 29 RCTs (40 papers) involving 35,119 mother and infant pairs reporting on the effects of aforementioned interventions on linear growth outcomes. Our NMA on LAZ found that compared to standard-of-care, multiple micronutrients administered to infants (MMN-C) improved LAZ (mean difference: 0.20; 95% credible interval [CrI]: 0.03,0.35), whereas supplementing breastfeeding mothers with MMN did not (MMN-M, mean difference: -0.02, 95%CrI: -0.18,0.13). No interventions including MMN-C (relative risk: 0.74; 95%CrI: 0.36,1.44) reduced risk for stunting compared to standard-of-care. Kangaroo care, on the other hand, improved head circumference (mean difference: 0.20 cm/week; 95% confidence intervals [CI]: 0.09,0.31 cm/week) and length (mean difference: 0.23 cm/week; 95%CI: 0.10,0.35 cm/week) compared to standard-of-care.   Conclusion: Our study found important improvements for kangaroo care, but we did not find sufficient evidence for other interventions. Registration: PROSPERO CRD42018110450; registered on 17 October 2018.

Zinc supplementation for the promotion of growth and prevention of infections in infants less than six months of age

BACKGROUND

Zinc is a vital micronutrient for humans and is essential for protein synthesis, cell growth, and differentiation. Severe zinc deficiency can lead to slower physical, cognitive and sexual growth, cause skin disorders, decrease immunity, increase incidence of acute illnesses in infants and children and contribute to childhood stunting. By estimation, 17.3% of the world population is at risk of inadequate zinc intake. Such nutritional impairment increases the risk of diarrhoea and pneumonia by 20%, as well as leads to a global loss of more than 16 million disability-adjusted life years in children less than five years of age. Not only does zinc deficiency affect lives, it adds to the considerable financial burden on depleted resources in countries that are most affected. By preventing or curing this deficiency, we can improve childhood mortality, morbidity and growth.

OBJECTIVES

To assess the effectiveness of zinc supplementation for the promotion of growth, reduction in mortality, and the prevention of infections in infants less than six months of age.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Group to search the Cochrane Central Register of Controlled Trials (CENTRAL 2018, Issue 4), MEDLINE via PubMed (1966 to 18 May 2018), Embase (1980 to 18 May 2018), and CINAHL (1982 to 18 May 2018). We also searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials. An updated search from 1 January 2018 to 29 January 2020 was run in the following databases: CENTRAL via CRS Web, MEDLINE via Ovid, and CINAHL via EBSCOhost.

SELECTION CRITERIA

All randomised controlled (individual and cluster randomised) and quasi-randomised trials of zinc supplementation in healthy, term infants, less than six months of age comparing infant mortality, incidence of diarrhoea or respiratory illnesses, growth and/or serum zinc levels were eligible.

DATA COLLECTION AND ANALYSIS

Two review authors screened search results (title and abstracts) and relevant full texts. Studies fulfilling prespecified inclusion criteria were included with any disagreements resolved by consensus. Extraction and analysis were then conducted. We used the GRADE approach to assess the quality of evidence as indicated by certainty in effect estimates.

MAIN RESULTS

Eight studies (with 85,629 infants) were included and five studies were meta-analysed, out of which four studies compared zinc with placebo, and one compared zinc plus riboflavin versus riboflavin. Certain growth outcomes after six months of intervention (Weight for Age Z-scores (WAZ) (standardised mean difference) (SMD) 0.16, 95% CI 0.03 to 0.29; three studies, n = 955; fixed-effect; heterogeneity Chi² P = 0.96); I² = 0%); change in WAZ (SMD 0.16, 95% CI 0.07 to 0.25; one study, n = 386; fixed-effect); (Weight-for-Length Z-score (WLZ) (SMD 0.15, 95% CI 0.02 to 0.28; three studies, n = 955; fixed-effect; heterogeneity: Chi² P = 0.81); I² = 0%); (change in WLZ (SMD 0.17, 95% CI 0.06 to 0.28; one study, n = 386; fixed-effect)) were positively affected by zinc supplementation compared to placebo. A single study reported no difference in the incidence of diarrhoea and lower respiratory tract infection with zinc supplementation. Zinc had no effect on mortality in children younger than 12 months. When zinc plus riboflavin was compared to riboflavin only, significant improvement was observed in the incidence of wasting at 24 months (risk ratio (RR) 0.59, 95% CI 0.37 to 0.96; one study, n = 296; fixed-effect), but significant worsening of incidence of stunting was present at 21 months (RR 1.53, 95% CI 1.09 to 2.16; one study, n = 298; fixed-effect).

AUTHORS' CONCLUSIONS

There was a significant positive impact of zinc supplementation on WAZ and WLZ after six months of intervention in infants compared to placebo. When a combined supplement of zinc and riboflavin was compared to riboflavin, there was a significant reduction in wasting at 24 months, but stunting at 21 months was negatively affected. Although included trials were of good-to-moderate quality, evidence that could be meta-analysed was based on a few studies which affected the overall quality of results. Regardless, there is a need for strong trials conducted in infants younger than six months before a strong recommendation can be made supporting zinc supplementation in this age group.

Interventions to improve linear growth during exclusive breastfeeding life-stage for children aged 0-6 months living in low- and middle-income countries: a systematic review and network and pairwise meta-analyses

Background: Exclusive breastfeeding (EBF) during the first six months of life is critical for child's linear growth. While there is strong evidence in favor of EBF, the evidence with regards to other interventions for linear growth is unclear. We evaluated intervention domains of micronutrients, food supplements, deworming, maternal education, water sanitation and hygiene (WASH), and kangaroo care, for their comparative effectiveness on linear growth. Methods: For this review, we searched for randomized clinical trials (RCTs) of the interventions provided to infants aged 0-6 months and/or their breastfeeding mothers in low- and middle-income countries reporting on length-for-age z-score (LAZ), stunting, length, and head circumference. We searched for reports published until September 17 th, 2019 and hand-searched bibliographies of existing reviews. For LAZ and stunting, we used network meta-analysis (NMA) to compare the effects of all interventions except for kangaroo care, where we used pairwise meta-analysis to compare its effects versus standard-of-care. For length and head circumference, we qualitatively summarized our findings. Results: We found 29 RCTs (40 papers) involving 35,119 mother and infant pairs reporting on the effects of aforementioned interventions on linear growth outcomes. Our NMA on LAZ found that compared to standard-of-care, multiple micronutrients administered to infants (MMN-C) improved LAZ (mean difference: 0.20; 95% credible interval [CrI]: 0.03,0.35), whereas supplementing breastfeeding mothers with MMN did not (MMN-M, mean difference: -0.02, 95%CrI: -0.18,0.13). No interventions including MMN-C (relative risk: 0.74; 95%CrI: 0.36,1.44) reduced risk for stunting compared to standard-of-care. Kangaroo care, on the other hand, improved head circumference (mean difference: 0.20 cm/week; 95% confidence intervals [CI]: 0.09,0.31 cm/week) and length (mean difference: 0.23 cm/week; 95%CI: 0.10,0.35 cm/week) compared to standard-of-care.   Conclusion: Our study found important improvements for kangaroo care, but we did not find sufficient evidence for other interventions. Registration: PROSPERO CRD42018110450; registered on 17 October 2018.

They Are What You Eat: Can Nutritional Factors during Gestation and Early Infancy Modulate the Neonatal Immune Response?

The ontogeny of the human immune system is sensitive to nutrition even in the very early embryo, with both deficiency and excess of macro- and micronutrients being potentially detrimental. Neonates are particularly vulnerable to infectious disease due to the immaturity of the immune system and modulation of nutritional immunity may play a role in this sensitivity. This review examines whether nutrition around the time of conception, throughout pregnancy, and in early neonatal life may impact on the developing infant immune system.

Oral zinc for treating diarrhoea in children

BACKGROUND

In developing countries, diarrhoea causes around 500,000 child deaths annually. Zinc supplementation during acute diarrhoea is currently recommended by the World Health Organization (WHO) and the United Nations Children's Fund (UNICEF).

OBJECTIVES

To evaluate oral zinc supplementation for treating children with acute or persistent diarrhoea.

SEARCH METHODS

We searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL (the Cochrane Library 2016, Issue 5), MEDLINE, Embase, LILACS, CINAHL, mRCT, and reference lists up to 30 September 2016. We also contacted researchers.

SELECTION CRITERIA

Randomized controlled trials (RCTs) that compared oral zinc supplementation with placebo in children aged one month to five years with acute or persistent diarrhoea, including dysentery.

DATA COLLECTION AND ANALYSIS

Both review authors assessed trial eligibility and risk of bias, extracted and analysed data, and drafted the review. The primary outcomes were diarrhoea duration and severity. We summarized dichotomous outcomes using risk ratios (RR) and continuous outcomes using mean differences (MD) with 95% confidence intervals (CI). Where appropriate, we combined data in meta-analyses (using either a fixed-effect or random-effects model) and assessed heterogeneity.We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

Thirty-three trials that included 10,841 children met our inclusion criteria. Most included trials were conducted in Asian countries that were at high risk of zinc deficiency. Acute diarrhoeaThere is currently not enough evidence from well-conducted RCTs to be able to say whether zinc supplementation during acute diarrhoea reduces death or number of children hospitalized (very low certainty evidence).In children older than six months of age, zinc supplementation may shorten the average duration of diarrhoea by around half a day (MD -11.46 hours, 95% CI -19.72 to -3.19; 2581 children, 9 trials, low certainty evidence), and probably reduces the number of children whose diarrhoea persists until day seven (RR 0.73, 95% CI 0.61 to 0.88; 3865 children, 6 trials, moderate certainty evidence). In children with signs of malnutrition the effect appears greater, reducing the duration of diarrhoea by around a day (MD -26.39 hours, 95% CI -36.54 to -16.23; 419 children, 5 trials, high certainty evidence).Conversely, in children younger than six months of age, the available evidence suggests zinc supplementation may have no effect on the mean duration of diarrhoea (MD 5.23 hours, 95% CI -4.00 to 14.45; 1334 children, 2 trials, moderate certainty evidence), or the number of children who still have diarrhoea on day seven (RR 1.24, 95% CI 0.99 to 1.54; 1074 children, 1 trial, moderate certainty evidence).None of the included trials reported serious adverse events. However, zinc supplementation increased the risk of vomiting in both age groups (children greater than six months of age: RR 1.57, 95% CI 1.32 to 1.86; 2605 children, 6 trials, moderate certainty evidence; children less than six months of age: RR 1.54, 95% CI 1.05 to 2.24; 1334 children, 2 trials, moderate certainty evidence). Persistent diarrhoeaIn children with persistent diarrhoea, zinc supplementation probably shortens the average duration of diarrhoea by around 16 hours (MD -15.84 hours, 95% CI -25.43 to -6.24; 529 children, 5 trials, moderate certainty evidence).

AUTHORS' CONCLUSIONS

In areas where the prevalence of zinc deficiency or the prevalence of malnutrition is high, zinc may be of benefit in children aged six months or more. The current evidence does not support the use of zinc supplementation in children less six months of age, in well-nourished children, and in settings where children are at low risk of zinc deficiency.

Effect of Zinc Intake on Growth in Infants: A Meta-analysis

A systematic review and meta-analysis of available randomized controlled trials (RCTs) was conducted to evaluate the effect of zinc (Zn) intake on growth in infants. Out of 5500 studies identified through electronic searches and reference lists, 19 RCTs were selected after applying the exclusion/inclusion criteria. The influence of Zn intake on growth was considered in the overall meta-analysis. Other variables were also taken into account as possible effect modifiers: doses of Zn intake, intervention duration, nutritional status, and risk of bias. From each select growth study, final measures of weight, length, mid upper arm circumference (MUAC), head circumference, weight for age z-score (WAZ), length for age z-score (LAZ), and weight for length z-score (WLZ) were assessed. Pooled β and 95% confidence interval (CI) were calculated. Additionally, we carried out a sensitivity analysis. Zn intake was not associated with weight, length, MUAC, head circumference, and LAZ in the pooled analyses. However, Zn intake had a positive and statistically effect on WAZ (β = 0.06; 95%CI 0.02 to 0.10) and WLZ (β = 0.05; 95%CI 0.01 to 0.08). The dose-response relationship between Zn intake and these parameters indicated that a doubling of Zn intake increased WAZ and WLZ by approximately 4%. Substantial heterogeneity was present only in length analyses (I(2) = 45%; p = 0.03). Zn intake was positively associated with length values at short time (four to 20 weeks) (β = 0.01; CI 95% 0 to 0.02) and at medium doses of Zn (4.1 to 8 mg/day) (β = 0.003; CI 95% 0 to 0.01). Nevertheless, the effect magnitude was small. Our results indicate that Zn intake increases growth parameters of infants. Nonetheless, interpretation of these results should be carefully considered.

Zinc supplementation for the prevention of pneumonia in children aged 2 months to 59 months

BACKGROUND

Pneumonia is a leading cause of morbidity and mortality in children younger than five years of age. Most deaths occur during infancy and in low-income countries. Daily zinc supplements have been reported to prevent acute lower respiratory tract infection (LRTI) and reduce child mortality. This is an update of a review first published in 2010.

OBJECTIVES

To evaluate the effectiveness of zinc supplementation in the prevention of pneumonia in children aged two to 59 months.

SEARCH METHODS

We searched CENTRAL (Issue 21 October 2016), MEDLINE (1966 to October 2016), Embase (1974 to October 2016), LILACS (1982 to October 2016), CINAHL (1981 to October 2016), Web of Science (1985 to October 2016) and IMSEAR (1980 to October 2016).

SELECTION CRITERIA

Randomised controlled trials (RCTs) evaluating zinc supplementation for the prevention of pneumonia in children aged from 2 months to 59 months.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data.

MAIN RESULTS

We did not identify any new studies for inclusion in this update. We included six studies that involved 5193 participants.Analysis showed that zinc supplementation reduced the incidence of pneumonia by 13% (fixed-effect risk ratio (RR) 0.87; 95% confidence interval (CI) 0.81 to 0.94, six studies, low-quality evidence) and prevalence of pneumonia by 41% (random-effects RR 0.59; 95% CI 0.35 to 0.99, one study, n = 609, low-quality evidence). On subgroup analysis, we found that zinc reduced the incidence of pneumonia defined by specific clinical criteria by 21% (i.e. confirmation by chest examination or chest radiograph) (fixed-effect RR 0.79; 95% CI 0.0.71 to 0.88, four studies, n = 3261), but had no effect on lower specificity pneumonia case definition (i.e. age-specific fast breathing with or without lower chest indrawing) (fixed-effect RR 0.95; 95% CI 0.86 to 1.06, four studies, n = 1932).

AUTHORS' CONCLUSIONS

Zinc supplementation in children is associated with a reduction in the incidence and prevalence of pneumonia.

Use of Serum Zinc Concentration as an Indicator of Population Zinc Status

Assessing the prevalence and severity of zinc deficiency in populations is critical to determine the need for and appropriate targeting of zinc intervention programs and to assess their effectiveness for improving the health and well-being of high-risk populations. However, there is very little information on the zinc status of populations worldwide due to the lack of consensus on appropriate biochemical indicators of zinc status. The objective of this review was to evaluate the use of serum zinc concentration as an indicator of population zinc status.

We have reviewed the response of serum zinc concentration to dietary zinc restriction and zinc supplementation. In addition, we completed pooled analyses of nine zinc intervention trials in young children to assess the relations between serum zinc concentration of individuals before treatment and their responses to zinc supplementation. Also, in updated combined analyses of previously published data, we investigated the relation between the mean initial serum zinc concentration of a study population and their mean growth responses to zinc supplementation in randomized intervention trials among children.

The results from depletion/repletion studies indicate that serum zinc concentrations respond appreciably to severe dietary zinc restriction, although there is considerable interindividual variation in these responses. There is also clear evidence that both individual and population mean serum zinc concentrations increase consistently during zinc supplementation, regardless of the initial level of serum zinc concentration. By contrast, an individual's serum zinc concentration does not reliably predict that person's response to zinc supplementation.

Serum zinc concentration can be considered a useful biomarker of a population's risk of zinc deficiency and response to zinc interventions, although it may not be a reliable indicator of individual zinc status.

Interventions to tackle malnutrition and its risk factors in children living in slums: a scoping review

CONTEXT

Children living in slums are at high risk of being malnourished. There are no published reviews on existing interventions promoting better nutrition for children living in slums and the risk factors for children's malnutrition. Improved understanding of the risk factors for malnutrition in slums communities and the impact of interventions on children's health can provide guidance to practitioners and decision-makers. The present review is designed to provide this information.

METHODS

The search included 30 electronic bibliographic databases and relevant eligible studies published up to December 2013.

RESULTS

The search located 1512 citations. Full text relevance screening was conducted on 226 studies and on abstracts for 16 studies. The final 58 unique studies included 22 on interventions and 38 on risk. All of the interventions were nutrition-specific, with nutritional intervention being the most dominant type. Seventy-three per cent of the interventions were assessed effective.

CONCLUSION

The findings stressed the gaps in knowledge in terms of quality assessment and programmatic recommendations to identify children who are the most at risk of malnutrition to appropriately target interventions. Finally, the review helped to inform a systematic review (Cochrane Systematic review protocol 2015) that will examine the impact of interventions on outcome measures.

Zinc Supplementation in Preterm Neonates and Neurological Development, A Randomized Controlled Trial

OBJECTIVE

To assess the effect of zinc supplementation on neuro-development and growth of preterm neonates.

SETTING

Referral neonatal unit of a teaching hospital.

DESIGN

Open-labeled Randomized controlled trial.

PARTICIPANTS

100 preterm neonates.

INTERVENTION

Participants randomized to receive oral zinc (study group) or not (controls).

MAIN OUTCOME MEASURES

Primary: Neuro-development status at 40 weeks post conceptional age and at 3 month corrected age using Amiel-Tison neurologic assessment. Secondary: anthropometry and serum alkaline phosphatase at 3 months corrected age.

RESULTS

At 40 weeks post-conceptional age, greater number of zinc supplemented infants demonstrated alertness and attention pattern normal for their age (P=0.02). Higher number of controls showed signs of hyper-excitability at 40 week post-conceptional age (P=0.001) and 3 months corrected age (P=0.003). At 3 month corrected age, mean serum alkaline phosphatase level was significantly higher in the study group compared to controls.

CONCLUSION

Zinc supplementation till 3 month corrected age in preterm breastfed infants improves alertness and attention pattern; and decreases signs of hyperexcitability, and proportion with abnormal reflexes.

Zinc supplementation for prevention of acute respiratory infections in infants: a randomized controlled trial

OBJECTIVE

To study the effect of 2 weeks of prophylactic zinc supplementation on incidence and duration of acute respiratory infections.

DESIGN

Randomized double blind controlled trial.

SETTING

Community based; urban resettlement area in North-East Delhi, India.

PARTICIPANTS

272 children aged 6-11 months with acute respiratory infections. Children receiving zinc supplement within the past 3 months, severely malnourished, immuno-deficient, on steroid therapy, with severe illness requiring hospitalization, or children of families likely to migrate from the study area were excluded.

INTERVENTION

Placebo (syrup base) or zinc (20 mg/5 mL elemental zinc as zinc sulfate) orally given for a period of 2 weeks.

MAIN OUTCOME MEASURE(S)

Incidence, type and duration of acute respiratory infections, and adverse effects.

RESULTS

No effect on incidence of acute respiratory infections was noted. A decrease of 15% (0.78-0.94) in days and 12% (0.78-0.94) in duration of episode in acute respiratory infections was observed. Incidence of acute lower respiratory infections decreased by 62% (0.26-0.36) and the effect remained for full five months of follow up. There were no drop outs due to side effects.

CONCLUSIONS

Prophylactic zinc supplementation for two weeks may reduce the morbidity due to acute lower respiratory infections but not overall rate of acute respiratory infections in infants aged 6-11 months in similar populations.

Daily Zinc but Not Multivitamin Supplementation Reduces Diarrhea and Upper Respiratory Infections in Tanzanian Infants: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial

BACKGROUND

Although various micronutrient regimens have been shown to prevent and treat common infectious diseases in children, the effects of daily multivitamin (MV) and/or zinc supplementation have not been widely evaluated in young African infants.

OBJECTIVE

The objective was to determine whether daily supplementation of HIV-unexposed Tanzanian infants with MVs or zinc reduces the risk of infectious morbidity compared with placebo.

METHODS

In a 2 × 2 factorial, double-blind, randomized controlled trial, 2400 infants who were 6 wk of age and born to HIV-negative mothers in a low-malaria setting were randomly assigned to receive daily oral supplementation of MVs (vitamin B complex and vitamins C and E), zinc, zinc + MVs, or placebo for 18 mo. Morbidity was assessed by study nurses at monthly visits and by physicians every 3 mo and/or when the child was acutely ill.

RESULTS

No significant differences were found in the percentage of nurse visits during which diarrhea, cough, or any other symptom were reported throughout the previous month when receiving either zinc or MVs. However, physician diagnoses of all types of diarrhea (RR = 0.88; 95% CI: 0.81, 0.96; P = 0.003), dysentery (RR = 0.84; 95% CI: 0.74, 0.95; P = 0.006), and acute upper respiratory infection (RR = 0.92; 95% CI: 0.88, 0.97; P = 0.0005) were significantly lower for infants supplemented with zinc than for those who did not receive zinc. Among the 2360 infants for whom vital status was obtained, there was a nonsignificant increase in all-cause mortality among infants who received zinc (HR = 1.80; 95% CI: 0.98, 3.31; P = 0.06) compared with those who did not receive zinc. MVs did not alter the rates of any recorded physician diagnoses or mortality. Neither zinc nor MVs reduced hospitalizations or unscheduled outpatient visits.

CONCLUSIONS

Daily zinc supplementation of Tanzanian infants beginning at the age of 6 wk may lower the burden of diarrhea and acute upper respiratory infections, but provision of MVs using the regimen in this trial did not confer additional benefit. This trial was registered at clinicaltrials.gov as NCT00421668.

Zinc supplements for preventing otitis media

BACKGROUND

Otitis media is inflammation of the middle ear and is usually caused by infection. It affects people of all ages but is particularly common in young children. Around 164 million people worldwide have long-term hearing loss caused by this condition, 90% of them in low-income countries. As zinc supplements prevent pneumonia in disadvantaged children, we wanted to investigate whether zinc supplements could also prevent otitis media.

OBJECTIVES

To evaluate whether zinc supplements prevent otitis media in adults and children of different ages.

SEARCH METHODS

We searched CENTRAL (2014, Issue 1), MEDLINE (1950 to February week 4, 2014) and EMBASE (1974 to March 2014).

SELECTION CRITERIA

Randomised, placebo-controlled trials of zinc supplements given at least once a week for at least a month for preventing otitis media.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the eligibility and methodological quality of the included trials and extracted and analysed data. We summarised results using risk ratios (RRs) or rate ratios for dichotomous data and mean differences (MDs) for continuous data. We combined trial results where appropriate.

MAIN RESULTS

No new trials were identified for inclusion in this update. We identified 12 trials for inclusion, 10 of which contributed outcomes data. There were a total of 6820 participants. In trials of healthy children living in low-income communities, two trials did not demonstrate a significant difference between the zinc-supplemented and placebo groups in the numbers of participants experiencing an episode of definite otitis media during follow-up (3191 participants); another trial showed a significantly lower incidence rate of otitis media in the zinc group (rate ratio 0.69, 95% confidence interval (CI) 0.61 to 0.79, n = 1621). A small trial of 39 infants undergoing treatment for severe malnutrition suggested a benefit of zinc for the mean number of episodes of otitis media (mean difference (MD) -1.12 episodes, 95% CI -2.21 to -0.03). Zinc supplements did not seem to cause any serious adverse events but a small minority of children were reported to have vomited shortly after ingestion of the supplements. The trial evidence included is generally of good quality, with a low risk of bias.

AUTHORS' CONCLUSIONS

Evidence on whether zinc supplementation can reduce the incidence of otitis media in healthy children under the age of five years living in low- and middle-income countries is mixed. There is some evidence of benefit in children being treated for marasmus (severe malnutrition), but this is based on one small trial and should therefore be treated with caution.

Zinc supplementation for preventing mortality, morbidity, and growth failure in children aged 6 months to 12 years of age

BACKGROUND

Zinc deficiency is prevalent in low- and middle-income countries, and contributes to significant diarrhoea-, pneumonia-, and malaria-related morbidity and mortality among young children. Zinc deficiency also impairs growth.

OBJECTIVES

To assess the effects of zinc supplementation for preventing mortality and morbidity, and for promoting growth, in children aged six months to 12 years of age.

SEARCH METHODS

Between December 2012 and January 2013, we searched CENTRAL, MEDLINE, MEDLINE In-Process and Other Non-Indexed Citations, Embase, African Index Medicus, Conference Proceedings Citation Index, Dissertation Abstracts, Global Health, IndMED, LILACS, WHOLIS, metaRegister of Controlled Trials, and WHO ICTRP.

SELECTION CRITERIA

Randomised controlled trials of preventive zinc supplementation in children aged six months to 12 years compared with no intervention, a placebo, or a waiting list control. We excluded hospitalised children and children with chronic diseases or conditions. We excluded food fortification or intake, sprinkles, and therapeutic interventions.

DATA COLLECTION AND ANALYSIS

Two authors screened studies, extracted data, and assessed risk of bias. We contacted trial authors for missing information.

MAIN RESULTS

We included 80 randomised controlled trials with 205,401 eligible participants. We did not consider that the evidence for the key analyses of morbidity and mortality outcomes were affected by risk of bias. The risk ratio (RR) for all-cause mortality was compatible with a reduction and a small increased risk of death with zinc supplementation (RR 0.95, 95% confidence interval (CI) 0.86 to 1.05, 14 studies, high-quality evidence), and also for cause-specific mortality due to diarrhoea (RR 0.95, 95% CI 0.69 to 1.31, four studies, moderate-quality evidence), lower respiratory tract infection (LRTI) (RR 0.86, 95% CI 0.64 to 1.15, three studies, moderate-quality evidence), or malaria (RR 0.90, 95% CI 0.77 to 1.06, two studies, moderate-quality evidence).Supplementation reduced diarrhoea morbidity, including the incidence of all-cause diarrhoea (RR 0.87, 95% CI 0.85 to 0.89, 26 studies, moderate-quality evidence), but the results for LRTI and malaria were imprecise: LRTI (RR 1, 95% CI 0.94 to 1.07, 12 studies, moderate-quality evidence); malaria (RR 1.05, 95% 0.95 to 1.15, four studies, moderate-quality evidence).There was moderate-quality evidence of a very small improvement in height with supplementation (standardised mean difference (SMD) -0.09, 95% CI -0.13 to -0.06; 50 studies), but the size of this effect might not be clinically important. There was a medium to large positive effect on zinc status.Supplementation was associated with an increase in the number of participants with at least one vomiting episode (RR 1.29, 95% CI 1.14 to 1.46, five studies, high-quality evidence). We found no clear evidence of benefit or harm of supplementation with regard to haemoglobin or iron status. Supplementation had a negative effect on copper status.

AUTHORS' CONCLUSIONS

In our opinion, the benefits of preventive zinc supplementation outweigh the harms in areas where the risk of zinc deficiency is relatively high. Further research should determine optimal intervention characteristics such as supplement dose.

Enteral zinc supplementation and growth in extremely-low-birth-weight infants with chronic lung disease

OBJECTIVE

Zinc deficiency causes growth deficits. Extremely-low-birth-weight (ELBW) infants with chronic lung disease (CLD), also known as bronchopulmonary dysplasia, experience growth failure and are at risk for zinc deficiency. We hypothesized that enteral zinc supplementation would increase weight gain and linear growth.

METHODS

A cohort of infants was examined retrospectively at a single center between January 2008 and December 2011. CLD was defined as the need for oxygen at 36 weeks postmenstrual age. Zinc supplementation was started in infants who had poor weight gain. Infants' weight gain and linear growth were compared before and after zinc supplementation using the paired t test.

RESULTS

A total of 52 ELBW infants with CLD met entry criteria. Mean birth weight was 682 ± 183 g, and gestational age was 25.3 ± 2 weeks. Zinc supplementation started at postmenstrual age 33 ± 2 weeks. Most infants received fortified human milk. Weight gain increased from 10.9 before supplementation to 19.9 g · kg(-1) · day(-1) after supplementation (P < 0.0001). Linear growth increased from 0.7 to 1.1 cm/week (P = 0.001).

CONCLUSIONS

Zinc supplementation improved growth in ELBW infants with CLD receiving human milk. Further investigation is warranted to reevaluate zinc requirements, markers, and balance.

Risk factors for severe acute lower respiratory infections in children: a systematic review and meta-analysis

AIM

To identify the risk factors in children under five years of age for severe acute lower respiratory infections (ALRI), which are the leading cause of child mortality.

METHODS

We performed a systematic review of published literature available in the public domain. We conducted a quality assessment of all eligible studies according to GRADE criteria and performed a meta-analysis to report the odds ratios for all risk factors identified in these studies.

RESULTS

We identified 36 studies that investigated 19 risk factors for severe ALRI. Of these, 7 risk factors were significantly associated with severe ALRI in a consistent manner across studies, with the following meta-analysis estimates of odds ratios (with 95% confidence intervals): low birth weight 3.18 (1.02-9.90), lack of exclusive breastfeeding 2.34 (1.42-3.88), crowding - more than 7 persons per household 1.96 (1.53-2.52), exposure to indoor air pollution 1.57 (1.06-2.31), incomplete immunization 1.83 (1.32-2.52), undernutrition - weight-for-age less than 2 standard deviations 4.47 (2.10-9.49), and HIV infection 4.15 (2.57-9.74).

CONCLUSION

This study highlights the role of the above seven risk factors in the development of severe pneumonia in under-five children. In addition, it emphasizes the need for further studies investigating other potential risk factors. Since these risk factors are potentially preventable, health policies targeted at reducing their prevalence provide a basis for decreasing the burden of childhood pneumonia.

Effect of zinc intake on serum/plasma zinc status in infants: a meta-analysis

A systematic review and meta-analysis of available randomised controlled trials (RCTs) was conducted to evaluate the effect of zinc (Zn) intake on serum/plasma Zn status in infants. Out of 5500 studies identified through electronic searches and reference lists, 13 RCTs were selected after applying the exclusion/inclusion criteria. The influence of Zn intake on serum/plasma Zn concentration was considered in the overall meta-analysis. Other variables were also taken into account as possible effect modifiers: doses of Zn intake, intervention duration, nutritional status and risk of bias. The pooled β of status was 0.09 [confidence interval (CI) 0.05 to 0.12]. However, a substantial heterogeneity was present in the analyses (I(2) = 98%; P = 0.00001). When we performed a meta-regression, the effect of Zn intake on serum/plasma Zn status changed depending on the duration of the intervention, the dose of supplementation and the nutritional situation (P ANCOVA = 0.054; <0.001 and <0.007, respectively). After stratifying the sample according to the effect modifiers, the results by duration of intervention showed a positive effect when Zn intake was provided during medium and long periods of time (4-20 weeks and >20 weeks). A positive effect was also seen when doses ranged from 8.1 to 12 mg day(-1). In all cases, the pooled β showed high evidence of heterogeneity. Zn supplementation increases serum/plasma Zn status in infants, although high evidence of heterogeneity was found. Further standardised research is urgently needed to reach evidence-based conclusions to clarify the role of Zn supplementation upon infant serum/plasma Zn status, particularly in Europe.

Effectiveness of zinc supplementation to full term normal infants: a community based double blind, randomized, controlled, clinical trial

The study was aimed to test whether zinc supplementation, if initiated early, can prevent stunting and promote optimum body composition in full term infants. For this, full term pregnant women from low income urban community were enrolled and were followed-up for 24 months postpartum. Body mass index (BMI) was calculated from maternal weight and height that were collected one month after delivery. Infants' weight, and length, head, chest and mid upper arm circumferences and skin fold thicknesses at triceps, biceps and subscapular area were collected at baseline (before randomization) and once in three months up till 24 months. Three hundred and twenty four infants were randomized and allocated to zinc (163) or placebo (161) groups respectively. Supplementation of zinc was initiated from 4 months of age and continued till children attained 18 months. The control (placebo) group of children received riboflavin 0.5 mg/day, whereas the intervention (zinc) group received 5 mg zinc plus riboflavin 0.5 mg/day. When infants were 18 months old, dietary intakes (in 78 children) were calculated by 24 hour diet recall method and hemoglobin, zinc, copper and vitamin A were quantified in blood samples collected from 70 children. The results showed prevalence of undernutrition (body mass index <18.5) in 37% of the mothers. Mean±SD calorie consumption and zinc intakes from diets in infants were 590±282.8 Kcal/day and 0.97±0.608 mg/day respectively. Multiple linear regression models demonstrated maternal weight as a strong predictor of infants' weight and length at 18 months of age. As expected, diarrhea duration impacted infants' linear growth and weight gain adversely. Zinc supplementation for a mean period of 190 days, starting from 4 months up to 18 months of age, in full term normal infants, consuming an average energy of 590 Kcal/day, had significant effect on the skin fold thicknesses, but not on their linear growth.

TRIAL REGISTRATION

Clinical Trail Registration India (CTRI) CTRI/2012/08/002884.

Oral zinc for treating diarrhoea in children

BACKGROUND

In developing countries, diarrhoea causes around two million child deaths annually. Zinc supplementation during acute diarrhoea is currently recommended by the World Health Organization and UNICEF.

OBJECTIVES

To evaluate oral zinc supplementation for treating children with acute or persistent diarrhoea.

SEARCH METHODS

In February 2012, we searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL (The Cochrane Library 2011, Issue 11), MEDLINE, EMBASE, LILACS, CINAHL, mRCT, and reference lists. We also contacted researchers.

SELECTION CRITERIA

Randomized controlled trials comparing oral zinc supplementation with placebo in children aged one month to five years with acute or persistent diarrhoea, including dysentery.

DATA COLLECTION AND ANALYSIS

Both authors assessed trial eligibility and risk of bias, extracted and analysed data, and drafted the review. Diarrhoea duration and severity were the primary outcomes. We summarized dichotomous outcomes using risk ratios (RR) and continuous outcomes using mean differences (MD) with 95% confidence intervals (CI). Where appropriate, we combined data in meta-analyses (using the fixed- or random-effects model) and assessed heterogeneity.The quality of evidence has been assessed using the GRADE methods

MAIN RESULTS

Twenty-four trials, enrolling 9128 children, met our inclusion criteria. The majority of the data is from Asia, from countries at high risk of zinc deficiency, and may not be applicable elsewhere. Acute diarrhoea. There is currently not enough evidence from well conducted randomized controlled trials to be able to say whether zinc supplementation during acute diarrhoea reduces death or hospitalization (very low quality evidence).In children aged greater than six months with acute diarrhoea, zinc supplementation may shorten the duration of diarrhoea by around 10 hours (MD -10.44 hours, 95% CI -21.13 to 0.25; 2175 children, six trials, low quality evidence), and probably reduces the number of children whose diarrhoea persists until day seven (RR 0.73, 95% CI 0.61 to 0.88; 3865 children, six trials, moderate quality evidence). In children with signs of moderate malnutrition the effect appears greater, reducing the duration of diarrhoea by around 27 hours (MD -26.98 hours, 95% CI -14.62 to -39.34; 336 children, three trials, high quality evidence).Conversely, In children aged less than six months, the available evidence suggests zinc supplementation may have no effect on mean diarrhoea duration (MD 5.23 hours, 95% CI -4.00 to 14.45; 1334 children, two trials, low quality evidence), and may even increase the proportion of children whose diarrhoea persists until day seven (RR 1.24, 95% CI 0.99 to 1.54; 1074 children, one trial, moderate quality evidence).No trials reported serious adverse events, but zinc supplementation during acute diarrhoea causes vomiting in both age groups (RR 1.59, 95% 1.27 to 1.99; 5189 children, 10 trials, high quality evidence). Persistent diarrhoea. In children with persistent diarrhoea, zinc supplementation probably shortens the duration of diarrhoea by around 16 hours (MD -15.84 hours, 95% CI -25.43 to -6.24; 529 children, five trials, moderate quality evidence).

AUTHORS' CONCLUSIONS

In areas where the prevalence of zinc deficiency or the prevalence of moderate malnutrition is high, zinc may be of benefit in children aged six months or more.The current evidence does not support the use of zinc supplementation in children below six months of age.

Oral zinc for treating diarrhoea in children

BACKGROUND

In developing countries, diarrhoea causes around two million child deaths annually. Zinc supplementation during acute diarrhoea is currently recommended by the World Health Organization and UNICEF.

OBJECTIVES

To evaluate oral zinc supplementation for treating children with acute or persistent diarrhoea.

SEARCH METHODS

In February 2012, we searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL (The Cochrane Library 2011, Issue 11), MEDLINE, EMBASE, LILACS, CINAHL, mRCT, and reference lists. We also contacted researchers.

SELECTION CRITERIA

Randomized controlled trials comparing oral zinc supplementation with placebo in children aged one month to five years with acute or persistent diarrhoea, including dysentery.

DATA COLLECTION AND ANALYSIS

Both authors assessed trial eligibility and risk of bias, extracted and analysed data, and drafted the review. Diarrhoea duration and severity were the primary outcomes. We summarized dichotomous outcomes using risk ratios (RR) and continuous outcomes using mean differences (MD) with 95% confidence intervals (CI). Where appropriate, we combined data in meta-analyses (using the fixed- or random-effects model) and assessed heterogeneity.The quality of evidence has been assessed using the GRADE methods

MAIN RESULTS

Twenty-four trials, enrolling 9128 children, met our inclusion criteria. The majority of the data is from Asia, from countries at high risk of zinc deficiency, and may not be applicable elsewhere.Acute diarrhoeaThere is currently not enough evidence from well conducted randomized controlled trials to be able to say whether zinc supplementation during acute diarrhoea reduces death or hospitalization (very low quality evidence).In children aged greater than six months with acute diarrhoea, zinc supplementation may shorten the duration of diarrhoea by around 10 hours (MD -10.44 hours, 95% CI -21.13 to 0.25; 2091 children, five trials, low quality evidence), and probably reduces the number of children whose diarrhoea persists until day seven (RR 0.73, 95% CI 0.61 to 0.88; 3865 children, six trials, moderate quality evidence). In children with signs of moderate malnutrition the effect appears greater, reducing the duration of diarrhoea by around 27 hours (MD -26.98 hours, 95% CI -14.62 to -39.34; 336 children, three trials, high quality evidence).Conversely, In children aged less than six months, the available evidence suggests zinc supplementation may have no effect on mean diarrhoea duration (MD 5.23 hours, 95% CI -4.00 to 14.45; 1334 children, two trials, low quality evidence), and may even increase the proportion of children whose diarrhoea persists until day seven (RR 1.24, 95% CI 0.99 to 1.54; 1074 children, one trial, moderate quality evidence).No trials reported serious adverse events, but zinc supplementation during acute diarrhoea causes vomiting in both age groups (RR 1.59, 95% 1.27 to 1.99; 5189 children, 10 trials, high quality evidence).Persistent diarrhoeaIn children with persistent diarrhoea, zinc supplementation probably shortens the duration of diarrhoea by around 16 hours (MD -15.84 hours, 95% CI -25.43 to -6.24; 529 children, five trials, moderate quality evidence).

AUTHORS' CONCLUSIONS

In areas where the prevalence of zinc deficiency or the prevalence of moderate malnutrition is high, zinc may be of benefit in children aged six months or more.The current evidence does not support the use of zinc supplementation in children below six months of age.

Zinc supplements for preventing otitis media

BACKGROUND

Otitis media (OM) is inflammation of the middle ear and is usually caused by infection. It affects people of all ages but is particularly common in young children. Around 164 million people worldwide have long-term hearing loss caused by this condition, 90% of them in low-income countries. As zinc supplements prevent pneumonia in disadvantaged children, we wanted to investigate whether zinc supplements could also prevent OM.

OBJECTIVES

To evaluate whether zinc supplements prevent OM in adults and children of different ages.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL 2012, Issue 1) which includes the Cochrane Acute Respiratory Infections Groups' Specialised Register, MEDLINE (1950 to February week 1, 2012) and EMBASE (1974 to February 2012).

SELECTION CRITERIA

Randomised, placebo-controlled trials of zinc supplements given at least once a week for at least a month for preventing OM.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the eligibility and methodological quality of the included trials and extracted and analysed data. We summarised results using risk ratios (RRs) or rate ratios for dichotomous data and mean differences (MDs) for continuous data. We combined trial results where appropriate.

MAIN RESULTS

We identified 12 trials for inclusion, 10 of which contributed outcomes data. There was a total of 6820 participants. In trials of healthy children living in low-income communities, two trials did not demonstrate a significant difference between the zinc supplemented and placebo groups in the numbers of participants experiencing an episode of definite OM during follow-up (3191 participants); another trial showed a significantly lower incidence rate of OM in the zinc group (rate ratio 0.69, 95% confidence interval (CI) 0.61 to 0.79, n = 1621). A small trial of 39 infants undergoing treatment for severe malnutrition suggested a benefit of zinc for the mean number of episodes of OM (mean difference (MD) -1.12 episodes, 95% CI -2.21 to -0.03). Zinc supplements did not seem to cause any serious adverse events but a small minority of children were reported to have vomited shortly after ingestion of the supplements. The trial evidence included is generally of good quality, with a low risk of bias.

AUTHORS' CONCLUSIONS

Evidence on whether zinc supplementation can reduce the incidence of OM in healthy children under the age of five years living in low- and middle-income countries is mixed. There is some evidence of benefit in children being treated for marasmus (severe malnutrition) but this is based on one small trial and should therefore be treated with caution.

Effect of zinc supplementation on growth of low birth weight infants aged 1-6 mo in Ardabil, Iran

OBJECTIVE

To assess the effect of zinc supplementation on growth of low birth weight (LBW) infants aged 1-6 mo.

METHODS

LBW infants were enrolled at birth and randomly assigned to receive 5 mg elemental Zn per day (n = 45) or placebo (n = 45) until 6 mo of age. They were followed monthly for information on compliance; anthropometric measurements were performed monthly.

RESULTS

After randomization, 5 infants from zinc group and 9 from placebo group were excluded. At 6 mo of age, significantly greater weight gains were observed in the zinc than in the placebo group (4995 ± 74 g in zinc group vs. 3896 ± 865 g in placebo group, p=0.036). Length gain during the study period improved in zinc group (16.9 ± 8.2 cm vs. 15.1 ± 4.1 cm, p=0.039); after zinc supplementation head circumference were increased (8.7 ± 1.4 cm vs. 7.4 ± 1.5 cm p < 0.001). In male infants, total weight gain and height and head circumference gain were higher in the zinc than in the placebo group. However, only head circumference change was statistically significant. A similar trend was observed among female infants, but these differences were not statistically significant. There was no significant relation between breast-feeding status and the main outcome variables.

CONCLUSIONS

Infants in the present study showed improvements in growth rate, but more studies are required in this field to confirm this fact.

Neonatal zinc supplementation for prevention of mortality and morbidity in breastfed low birth weight infants: systematic review of randomized controlled trials

OBJECTIVES

To evaluate whether zinc supplements prevent mortality and morbidity in breastfed low birth weight infants.

METHODS

All randomized or qausi-randomized trials with individual or cluster allocation and using concurrent controls were included. Study population included LBW infants irrespective of gestational status who were exclusively or predominantly breastfed at the initiation of intervention. Intervention comprised zinc salts given as tablets or syrups orally to provide at least 1 RDA of elemental zinc for at least a period of 14 days, introduced within one month of birth. Electronic databases were searched irrespective of language and publication status.

FINDINGS

Three trials from developing countries met the inclusion criteria. Limited data did not indicate a reduced risk of mortality (1 trial, RR=1.11; 95% CI 0.57 to 2.18 at one year), hospitalization rate (1 trial, odds ratio 1.10; 95% CI 0.87 to 1.39), acute respiratory infection (1 trial), or diarrhea (2 trials). However, the trial reporting on mortality was not adequately powered for evaluating this outcome. There was no evidence of an increase in weight (3 trials) or height (2 trials) at either 6 months or one year of age, or of an increased risk of vomiting following zinc supplementation. Serum zinc levels at the end of intervention were significantly higher in the supplemented group (2 trials).

CONCLUSIONS

In view of no convincing evidence of benefits from the limited data available, currently there is no justification for recommending routine zinc supplementation for breastfed LBW newborns in developing countries.

What zinc supplementation does and does not achieve in diarrhea prevention: a systematic review and meta-analysis

BACKGROUND

Prevention of diarrhea has presented indomitable challenges. A preventive strategy that has received significant interest is zinc supplementation. Existing literature including quantitative meta-analyses and systematic reviews tend to show that zinc supplementation is beneficial however evidence to the contrary is augmenting. We therefore conducted an updated and comprehensive meta-analytical synthesis of the existing literature on the effect of zinc supplementation in prevention of diarrhea.

METHODS

EMBASE®, MEDLINE ® and CINAHL® databases were searched for published reviews and meta-analyses on the use of zinc supplementation for the prevention childhood diarrhea. Additional RCTs published following the meta-analyses were also sought. Effect of zinc supplementation on the following five outcomes was studied: incidence of diarrhea, prevalence of diarrhea, incidence of persistent diarrhea, incidence of dysentery and incidence of mortality. The published RCTs were combined using random-effects meta-analyses, subgroup meta-analyses, meta-regression, cumulative meta-analyses and restricted meta-analyses to quantify and characterize the role of zinc supplementation with the afore stated outcomes.

RESULTS

We found that zinc supplementation has a modest beneficial association (9% reduction) with incidence of diarrhea, a stronger beneficial association (19% reduction) with prevalence of diarrhea and occurrence of multiple diarrheal episodes (28% reduction) but there was significant unexplained heterogeneity across the studies for these associations. Age, continent of study origin, zinc salt and risk of bias contributed significantly to between studies heterogeneity. Zinc supplementation did not show statistically significant benefit in reducing the incidence of persistent diarrhea, dysentery or mortality. In most instances, the 95% prediction intervals for summary relative risk estimates straddled unity.

CONCLUSIONS

Demonstrable benefit of preventive zinc supplementation was observed against two of the five diarrhea-related outcomes but the prediction intervals straddled unity. Thus the evidence for a preventive benefit of zinc against diarrhea is inconclusive. Continued efforts are needed to better understand the sources of heterogeneity. The outcomes of zinc supplementation may be improved by identifying subgroups that need zinc supplementation.

Effect of preventive zinc supplementation on linear growth in children under 5 years of age in developing countries: a meta-analysis of studies for input to the lives saved tool

Introduction

Zinc plays an important role in cellular growth, cellular differentiation and metabolism. The results of previous meta-analyses evaluating effect of zinc supplementation on linear growth are inconsistent. We have updated and evaluated the available evidence according to Grading of Recommendations, Assessment, Development and Evaluation (GRADE) criteria and tried to explain the difference in results of the previous reviews.

Methods

A literature search was done on PubMed, Cochrane Library, IZiNCG database and WHO regional data bases using different terms for zinc and linear growth (height). Data were abstracted in a standardized form. Data were analyzed in two ways i.e. weighted mean difference (effect size) and pooled mean difference for absolute increment in length in centimeters. Random effect models were used for these pooled estimates. We have given our recommendations for effectiveness of zinc supplementation in the form of absolute increment in length (cm) in zinc supplemented group compared to control for input to Live Saves Tool (LiST).

Results

There were thirty six studies assessing the effect of zinc supplementation on linear growth in children < 5 years from developing countries. In eleven of these studies, zinc was given in combination with other micronutrients (iron, vitamin A, etc). The final effect size after pooling all the data sets (zinc ± iron etc) showed a significant positive effect of zinc supplementation on linear growth [Effect size: 0.13 (95% CI 0.04, 0.21), random model] in the developing countries. A subgroup analysis by excluding those data sets where zinc was supplemented in combination with iron showed a more pronounced effect of zinc supplementation on linear growth [Weighed mean difference 0.19 (95 % CI 0.08, 0.30), random model]. A subgroup analysis from studies that reported actual increase in length (cm) showed that a dose of 10 mg zinc/day for duration of 24 weeks led to a net a gain of 0.37 (±0.25) cm in zinc supplemented group compared to placebo. This estimate is recommended for inclusion in Lives Saved Tool (LiST) model.

Conclusions

Zinc supplementation has a significant positive effect on linear growth, especially when administered alone, and should be included in national strategies to reduce stunting in children < 5 years of age in developing countries.

Preventive zinc supplementation in developing countries: impact on mortality and morbidity due to diarrhea, pneumonia and malaria

Background

Zinc deficiency is commonly prevalent in children in developing countries and plays a role in decreased immunity and increased risk of infection. Preventive zinc supplementation in healthy children can reduce mortality due to common causes like diarrhea, pneumonia and malaria. The main objective was to determine all-cause mortality and cause-specific mortality and morbidity in children under five in developing countries for preventive zinc supplementation.

Data sources/ review methods

A literature search was carried out on PubMed, the Cochrane Library and the WHO regional databases to identify RCTs on zinc supplementation for greater than 3 months in children less than 5 years of age in developing countries and its effect on mortality was analyzed.

Results

The effect of preventive zinc supplementation on mortality was given in eight trials, while cause specific mortality data was given in five of these eight trials. Zinc supplementation alone was associated with a statistically insignificant 9% (RR = 0.91; 95% CI: 0.82, 1.01) reduction in all cause mortality in the intervention group as compared to controls using a random effect model. The impact on diarrhea-specific mortality of zinc alone was a non-significant 18% reduction (RR = 0.82; 95% CI: 0.64, 1.05) and 15% for pneumonia-specific mortality (RR = 0.85; 95% CI: 0.65, 1.11). The incidence of diarrhea showed a 13% reduction with preventive zinc supplementation (RR = 0.87; 95% CI: 0.81, 0.94) and a 19% reduction in pneumonia morbidity (RR = 0.81; 95% CI: 0.73, 0.90). Keeping in mind the direction of effect of zinc supplementation in reducing diarrhea and pneumonia related morbidity and mortality; we considered all the outcomes for selection of effectiveness estimate for inclusion in the LiST model. After application of the CHERG rules with consideration to quality of evidence and rule # 6, we used the most conservative estimates as a surrogate for mortality. We, therefore, conclude that zinc supplementation in children is associated with a reduction in diarrhea mortality of 13% and pneumonia mortality of 15% for inclusion in the LiST tool. Preventive zinc supplementation had no effect on malaria specific mortality (RR = 0.90; 95% CI: 0.77, 1.06) or incidence of malaria (RR=0.92; 95 % CI 0.82-1.04)

Conclusion

Zinc supplementation results in reductions in diarrhea and pneumonia mortality.

Impact of flooding on feeding practices of infants and young children in Dhaka, Bangladesh Slums: what are the coping strategies?

Previous research has shown that urban slums are hostile environments for the growth of infants and young children (IYC). Flooding is a hazard commonly found in Dhaka slums (Bangladesh) which negatively impacts IYC's nutritional and health status. This paper aims 1) to identify the impact of flooding on IYC's feeding practices, and 2) to explore the coping strategies developed by caregivers. Qualitative data (participant observation and semi-structured interviews) and quantitative data (household questionnaire and anthropometric measurements) collected in slums in Dhaka (n=18 mothers, n=5 community health workers, and n=55 children) were analysed. The subjects of the interviews were mothers and Bangladesh Rural Advancement Committee (BRAC) community health workers living and working in the slums. Research findings showed that breastfeeding and complementary feeding practices for IYC were poor and inappropriate due to lack of knowledge, time, and resources in normal times and worse during flooding. One coping strategy developed by mothers purposely to protect their IYC's nutritional status was to decrease their personal food intake. Our research findings suggest that mothers perceived the negative impact of flooding on their IYC's nutritional health but did not have the means to prevent it. They could only maintain their health through coping strategies which had other negative consequences. The results suggests a holistic approach combining 1) provision of relief for nutritionally vulnerable groups during flooding, 2) support to mothers in their working role, 3) breastfeeding counseling and support to lactating mothers with difficulties, and 4) preventing malnutrition in under 2 year old children.

Zinc supplementation for the prevention of pneumonia in children aged 2 months to 59 months

BACKGROUND

Pneumonia is a leading cause of morbidity and mortality in children younger than five years of age. Most deaths occur during infancy and in low-income countries. Daily regimens of zinc have been reported to prevent acute lower respiratory tract infection and reduce child mortality.

OBJECTIVES

To evaluate the effectiveness of zinc supplementation in the prevention of pneumonia in children aged two to 59 months.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2010, Issue 2), which contains the Acute Respiratory Infections Group's Specialised Register, MEDLINE (1966 to January Week 2, 2010), EMBASE (1974 to January 2010) and LILACS (1985 to January 2010).

SELECTION CRITERIA

Randomised controlled trials (RCTs) evaluating supplementation of zinc for the prevention of pneumonia in children aged 2 to 59 months of age.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data.

MAIN RESULTS

We included six trials and 7850 participants in the meta-analysis. Analysis showed that zinc supplementation reduced the incidence of pneumonia by 13% (risk ratio (RR) 0.87; 95% confidence interval (CI) 0.81 to 0.94, fixed-effect, six studies) and prevalence of pneumonia by 41% (RR 0.59; 95% CI 0.35 to 0.99, random-effects, one study). On subgroup analysis, we found that zinc reduced the incidence of pneumonia defined by specific clinical criteria by 21% (i.e. confirmation by chest examination or chest radiograph) (RR 0.79; 95% CI 0.0.71 to 0.88, fixed-effect, four studies, n = 4591) but had no effect on lower specificity pneumonia case definition (i.e. age specific fast breathing with or without lower chest indrawing) (RR 0.95; 95% CI 0.86 to 1.06, fixed-effect, four studies, n = 3259).

AUTHORS' CONCLUSIONS

Zinc supplementation in children is associated with a reduction in the incidence and prevalence of pneumonia, the leading cause of death in children.

Two weeks of zinc administration to Nepalese children with pneumonia does not reduce the incidence of pneumonia or diarrhea during the next six months

Diarrhea and pneumonia are the 2 main causes of death in children under 5 y of age. Short courses of zinc administration are now recommended for treatment of childhood diarrhea and some studies have also shown its beneficial effect on treatment of pneumonia. The objective of our study was to assess the efficacy of zinc administration (10 mg/d for children 2-11 mo and 20 mg/d for >or= 12 mo of age) for 14 d on preventing diarrheal and respiratory illnesses for 6 mo of follow-up. This was a randomized, double-blind, placebo-controlled trial in children 2-35 mo of age with community-acquired pneumonia. The number of illness episodes and time until the first episode of various illnesses were compared between the 2 study groups. After 14 d of zinc supplementation, plasma zinc was significantly higher in the group receiving zinc. However, this difference was not detectable at 1 and 2.5 mo after the end of zinc administration. Of 2628 enrolled cases, a total of 2599 (99%) were available for assessment after the completion of zinc supplementation. The number of hospital visits and the median number of days until the first episode of pneumonia, diarrhea, and dysentery was similar in the 2 groups. The hazard ratios (95% CI) were 1.02 (0.92, 1.14) for nonsevere pneumonia, 1.11 (0.72, 1.73) for severe pneumonia, 1.07 (0.91, 1.26) for diarrhea, and 0.96 (0.69, 1.34) for dysentery. A short course of zinc supplementation given during an episode of pneumonia did not prevent diarrheal or respiratory illness over the next 6 mo.

Perinatal nutrition and immunity to infection

Epidemiological data provide strong evidence for a relationship between undernutrition and life-threatening infection in infants and children. However, the mechanisms that underlie this relationship are poorly understood. Through foetal life, infancy and childhood, the immune system undergoes a process of functional maturation. The adequacy of this process is dependent on environmental factors, and there is accumulating evidence of the impact of pre- and post-natal nutrition in this regard. This review outlines the impact of nutrition during foetal and infant development on the capacity to mount immune responses to infection. It provides an overview of the epidemiologic evidence for such a role and discusses the possible mechanisms involved.

Zinc supplements for preventing otitis media

BACKGROUND

Otitis media (inflammation of the middle ear, usually caused by infection) affects people of all ages, but is particularly common in young children. Around 164 million people worldwide have long-term hearing loss caused by this condition, 90% of them in low-income countries. Because zinc supplements prevent pneumonia in disadvantaged children, we wondered whether they prevent otitis media.

OBJECTIVES

To evaluate whether zinc supplements prevent otitis media in adults and children of different ages.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2009, issue 2) which includes the Acute Respiratory Infection Groups' Specialised Register; MEDLINE (1950 to June Week 1 2009); and EMBASE (1974 to June 2009).

SELECTION CRITERIA

Randomised, placebo-controlled trials of zinc supplements given at least once a week for at least a month for preventing otitis media.

DATA COLLECTION AND ANALYSIS

Two review authors assessed the eligibility and methodological quality of the included trials, extracted and analysed data and wrote the review. We summarised results using risk ratios or rate ratios for dichotomous data and mean differences for continuous data. We combined trial results where appropriate.

MAIN RESULTS

We identified 12 trials for inclusion, 10 of which contributed outcomes data. In trials of healthy children living in low-income communities, two trials did not demonstrate a significant difference between the zinc supplemented and placebo groups in the numbers of participants experiencing an episode of definite otitis media during follow up (3191 participants), while another trial showed a significantly lower incidence rate of otitis media in the zinc group (rate ratio 0.69, 95% confidence interval (CI) 0.61 to 0.79, n = 1621). A small trial of 39 infants undergoing treatment for severe malnutrition suggested a benefit of zinc on the mean number of episodes of otitis media (mean difference -1.12 episodes, 95% CI -2.21 to -0.03). Zinc supplements did not seem to cause any serious adverse events, but a small minority of children were reported to have vomited shortly after ingestion of the supplements.

AUTHORS' CONCLUSIONS

Evidence on whether zinc supplementation can reduce the incidence of otitis media in healthy children under the age of five years living in low- and middle-income countries is mixed. There is some evidence of benefit in children being treated for marasmus, but this is based on one small trial and should therefore be treated with caution.

Zinc supplementation for the prevention of acute lower respiratory infection in children in developing countries: meta-analysis and meta-regression of randomized trials

BACKGROUND

Routine zinc supplementation is a potential intervention for the prevention of acute lower respiratory infection (ALRI) in developing countries. However, discrepant findings from recent randomized trials remain unexplained.

METHODS

Randomized trials of zinc supplementation in young children in developing countries were identified by a systematic literature review. Trials included in the meta-analysis met specific criteria, including participants <5 years of age, daily/weekly zinc and control supplementation for greater than 3 months, active household surveillance for respiratory morbidity and use of a case definition that included at least one sign of lower respiratory tract illness. ALRI case definitions were classified on the basis of specificity/severity. Incidence rate ratios (IRRs) were pooled by random-effects models. Meta-regression and sub-group analysis were performed to assess potential sources of between-study heterogeneity.

RESULTS

Ten trials were eligible for inclusion (n = 49 450 children randomized). Zinc reduced the incidence of ALRI defined by specific clinical criteria [IRR 0.65, 95% confidence interval (CI) 0.52-0.82], but had no effect on lower-specificity ALRI case definitions based on caregiver report (IRR 1.01, 95% CI 0.91-1.12) or World Health Organization 'non-severe pneumonia' (0.96, 95% CI 0.86-1.08). By meta-regression, the effect of zinc was associated with ALRI case definition, but not with mean baseline age, geographic location, nutritional status or zinc dose.

CONCLUSIONS

Routine zinc supplementation reduced the incidence of childhood ALRI defined by relatively specific clinical criteria, but the effect was null if lower specificity case definitions were applied. The choice of ALRI case definition may substantially influence inferences from community trials regarding the efficacy of preventive interventions.

Effect of micronutrient supplementation on diarrhoeal disease among stunted children in rural South Africa

BACKGROUND/OBJECTIVE

The efficacy of zinc combined with vitamin A or multiple micronutrients in preventing diarrhoea is unclear in African countries with high prevalence of human immunodeficiency virus (HIV)-exposed children. Potential modifying factors, such as stunting, need to be addressed. The objective of this study was to determine whether adding zinc or zinc plus multiple micronutrients to vitamin A reduces diarrhoea incidence, and whether this differs between the strata of stunted or HIV-infected children.

METHODS

We analyzed data from a randomized, controlled, double-blinded trial (ClinicalTrials.gov NCT00156832) of prophylactic micronutrient supplementation to children aged 6-24 months. Three cohorts of children: 32 HIV-infected children, 154 HIV-uninfected children born to HIV-infected mothers and 187 uninfected children born to HIV-uninfected mothers, received vitamin A, vitamin A plus zinc or multiple micronutrients, which included vitamin A and zinc. The main outcome was incidence of diarrhoea. Poisson regression was used in intent-to-treat analyses. Stratified analyses followed testing for statistical interaction between intervention and stunting.

RESULTS

We observed no significant differences in overall diarrhoea incidence among treatment arms. Stunting modified this effect with stunted HIV-uninfected children having significantly lower diarrhoea incidence when supplemented with zinc or multiple micronutrients compared with vitamin A alone (2.04 and 2.23 vs 3.92 episodes/year, respectively, P=0.024). No meaningful subgroup analyses could be done in the cohort of HIV-infected children.

CONCLUSIONS

Compared with vitamin A alone, supplementation with zinc and with zinc and multiple micronutrients, reduced diarrhoea morbidity in stunted rural South African children. Efficacy of zinc supplementation in HIV-infected children needs confirmation in studies that represent the spectrum of disease severity and age groups.

Effects of zinc supplementation on physical growth in 2-5-year-old children

Physical growth disorders in under 5-year-old children are a common health problem in many countries including Iran. The aim of this study was to determine effects of supplemental zinc on physical growth in preschool children with retarded linear growth. This study was a community-based randomized controlled trial on 2-5-year-old children with height-for-age below 25th percentile of National Center for Health Statistics growth chart. Ninety children were randomly assigned in zinc group (ZG) or placebo group (PG). After 6 months of zinc or placebo supplementation, we followed up the children for another 6 months. Anthropometric indicators were measured before the intervention and then monthly for 11 months. Forty children in ZG and 45 in PG concluded the study. Zinc supplementation increased weight gain in boys (P = 0.04) and girls (P = 0.05) compared to placebo but had no significant effect on mid-upper arm circumference increment in either sexes. The most significant (P = 0.001) effect of Zinc supplementation was seen in boys' height increment at the end of follow-up period. Stunted growth rate in ZG changed significantly (P = 0.01) from 26.7% to 2.5% throughout the study. This study showed that daily supplementation of 5 mg elemental zinc for 6 months improves physical growth in terms of height increment and weight gain in children with undesirable linear growth, especially in boys.

Preventive Zinc Supplementation among Infants, Preschoolers, and Older Prepubertal Children

Zinc supplementation trials carried out among children have produced variable results, depending on the specific outcomes considered and the initial characteristics of the children who were enrolled. We completed a series of meta-analyses to examine the impact of preventive zinc supplementation on morbidity; mortality; physical growth; biochemical indicators of zinc, iron, and copper status; and indicators of behavioral development, along with possible modifying effects of the intervention results. Zinc supplementation reduced the incidence of diarrhea by ∼20%, but the impact was limited to studies that enrolled children with a mean initial age greater than 12 months. Among the subset of studies that enrolled children with mean initial age greater than 12 months, the relative risk of diarrhea was reduced by 27%. Zinc supplementation reduced the incidence of acute lower respiratory tract infections by ∼15%. Zinc supplementation yielded inconsistent impacts on malaria incidence, and too few trials are currently available to allow definitive conclusions to be drawn. Zinc supplementation had a marginal 6% impact on overall child mortality, but there was an 18% reduction in deaths among zinc-supplemented children older than 12 months of age. Zinc supplementation increased linear growth and weight gain by a small, but highly significant, amount. The interventions yielded a consistent, moderately large increase in mean serum zinc concentrations, and they had no significant adverse effects on indicators of iron and copper status. There were no significant effects on children's behavioral development, although the number of available studies is relatively small. The available evidence supports the need for intervention programs to enhance zinc status to reduce child morbidity and mortality and to enhance child growth. Possible strategies for delivering preventive zinc supplements are discussed.

Enhanced immunogenicity of an oral inactivated cholera vaccine in infants in Bangladesh obtained by zinc supplementation and by temporary withholding breast-feeding

The killed oral cholera vaccine Dukoral is recommended for adults and only children over 2 years of age, although cholera is seen frequently in younger children and there is an urgent need for a vaccine for them. Since decreased immunogenicity of oral vaccines in children in developing countries is a critical problem, we tested interventions to enhance responses to Dukoral. We evaluated the effect on the immune responses by temporarily withholding breast-feeding or by giving zinc supplementation. Two doses of Dukoral consisting of killed cholera vibrios and cholera B subunit were given to 6-18 months old Bangladeshi children (n=340) and safety and immunogenicity studied. Our results showed that two doses of the vaccine were safe and induced antibacterial (vibriocidal) antibody responses in 57% and antitoxin responses in 85% of the children. Immune responses were comparable after intake of one and two doses. Temporary withholding breast-feeding for 3 h before immunization or supplementation with 20 mg of zinc per day for 42 days resulted in increased magnitude of vibriocidal antibodies (77% and 79% responders, respectively). Administration of vaccines without buffer or in water did not result in reduction of vibriocidal responses. This study demonstrates that the vaccine is safe and immunogenic in children under 2 years of age and that simple interventions can enhance immune responses in young children.

Effects of micronutrients on growth of children under 5 y of age: meta-analyses of single and multiple nutrient interventions

BACKGROUND

Micronutrient interventions have received much attention as a cost-effective and promising strategy to improve child health, but their roles in improving child growth remain unclear.

OBJECTIVE

Meta-analyses of randomized controlled trials were conducted to evaluate the effect of micronutrient interventions on the growth of children aged <5 y old.

DESIGN

Eligible studies were identified by PubMed database searches and other methods. Weighted mean effect sizes and 95% CIs were calculated for changes in height, weight, and weight-for-height z scores (WHZ) by using random-effect models. Tests for publication bias were done by using funnel plots, heterogeneity, and stratified analyses by predefined characteristics.

RESULTS

Interventions including iron (n = 27) or vitamin A (n = 17) only had no significant effects on growth. Interventions including zinc only (n = 43) had a small positive effect (effect size = 0.06; 95% CI: 0.006, 0.11) on change in WHZ but no significant effect on height or weight gain. Multiple micronutrient interventions (n = 20) improved linear growth (0.09; 95% CI: 0.008, 0.17).

CONCLUSIONS

Our findings confirm earlier results of no benefits for interventions including iron and vitamin A only but differ from the earlier meta-analysis that found improvements in linear growth for zinc only interventions. This may be due to the improved nutritional status of children in the more recent studies. Multiple micronutrient interventions improve linear growth, but the benefits are small. Other strategies are needed to prevent stunting.

Zinc modifies the association between nasopharyngeal Streptococcus pneumoniae carriage and risk of acute lower respiratory infection among young children in rural Nepal

Nasopharyngeal (NP) carriage is necessary for Streptococcus pneumoniae (Spn) transmission and invasive infection. This study evaluated the effect of zinc prophylaxis on the association between NP colonization with Spn and acute lower respiratory infection (ALRI) in children aged 1-35 mo living in a rural district in southern Nepal. We compared carriage prevalence of Spn in 550 ALRI cases with that of healthy age- and season-matched controls. This study, conducted from December 2003 to July 2005, was nested in a community-randomized trial designed to evaluate the effect of zinc on morbidity and mortality in 1- to 36-mo-old children. They were randomized to receive either 10-mg tablets of zinc or placebo daily until discharge. Approximately 75% of cases and controls were Spn carriers. There was an interaction between zinc and Spn carriage (P = 0.091). Spn carriage increased the risk of ALRI in the placebo group [adjusted matched odds ratio (AMOR) = 2.57; P = 0.025] but not in the zinc group (AMOR = 0.95; P = 0.890). Among the subset of symptomatic cases and their controls, the odds of ALRI for Spn carriers in the placebo group was 30 times greater (AMOR = 78.09; P = 0.006) than in the zinc group (AMOR = 2.77; P = 0.288). These findings suggest that zinc prophylaxis may protect children against ALRI associated with carriage of Spn and that the effect may differ by infectious etiology.

Oral zinc for treating diarrhoea in children

BACKGROUND

Diarrhoea causes around two million child deaths annually. Zinc supplementation could help reduce the duration and severity of diarrhoea, and is recommended by the World Health Organization and UNICEF.

OBJECTIVES

To evaluate oral zinc supplementation for treating children with acute or persistent diarrhoea.

SEARCH STRATEGY

In November 2007, we searched the Cochrane Infectious Diseases Group Specialized Register, CENTRAL (The Cochrane Library 2007, Issue 4), MEDLINE, EMBASE, LILACS, CINAHL, mRCT, and reference lists. We also contacted researchers.

SELECTION CRITERIA

Randomized controlled trials comparing oral zinc supplementation (>/= 5 mg/day for any duration) with placebo in children aged one month to five years with acute or persistent diarrhoea, including dysentery.

DATA COLLECTION AND ANALYSIS

Both authors assessed trial eligibility and methodological quality, extracted and analysed data, and drafted the review. Diarrhoea duration and severity were the primary outcomes. We summarized dichotomous outcomes using risk ratios (RR) and continuous outcomes using mean differences (MD) with 95% confidence intervals (CI). Where appropriate, we combined data in meta-analyses (using the fixed- or random-effects model) and assessed heterogeneity.

MAIN RESULTS

Eighteen trials enrolling 6165 participants met our inclusion criteria. In acute diarrhoea, zinc resulted in a shorter diarrhoea duration (MD -12.27 h, 95% CI -23.02 to -1.52 h; 2741 children, 9 trials), and less diarrhoea at day three (RR 0.69, 95% CI 0.59 to 0.81; 1073 children, 2 trials), day five (RR 0.55, 95% CI 0.32 to 0.95; 346 children, 2 trials), and day seven (RR 0.71, 95% CI 0.52 to 0.98; 4087 children, 7 trials). The four trials (1458 children) that reported on diarrhoea severity used different units and time points, and the effect of zinc was less clear. Subgroup analyses by age (trials with only children aged less than six months) showed no benefit with zinc. Subgroup analyses by nutritional status, geographical region, background zinc deficiency, zinc type, and study setting did not affect the results' significance. Zinc also reduced the duration of persistent diarrhoea (MD -15.84 h, 95% CI -25.43 to -6.24 h; 529 children, 5 trials). Few trials reported on severity, and results were inconsistent. No trial reported serious adverse events, but vomiting was more common in zinc-treated children with acute diarrhoea (RR 1.71, 95% 1.27 to 2.30; 4727 children, 8 trials).

AUTHORS' CONCLUSIONS

In areas where diarrhoea is an important cause of child mortality, research evidence shows zinc is clearly of benefit in children aged six months or more.

Maternal zinc supplementation and growth in Peruvian infants

BACKGROUND

Little is known about how maternal zinc intake influences growth in utero and in postnatal life in humans.

OBJECTIVE

We aimed to assess the effect of maternal zinc supplementation during pregnancy on infant growth through age 1 y.

DESIGN

A double-blind, randomized controlled trial of prenatal zinc supplementation was conducted from 1995 to 1997 in Lima, Peru. Women (n = 1295) were enrolled at 15.6 +/- 4.6 wk gestation and assigned to receive daily supplements with zinc (15 mg Zn + 60 mg Fe + 250 microg folic acid) or without zinc (60 Fe + 250 microg folic acid) through pregnancy to 1 mo after delivery. At birth, 546 infants were followed for 12 mo to assess growth. Anthropometric measures of body size and composition were collected monthly, and morbidity and dietary intake surveillance was carried out weekly.

RESULTS

No differences in maternal socioeconomic characteristics by treatment group or follow-up period were found. Infants born to mothers prenatally supplemented with zinc had significantly (P < 0.05) larger average growth measures beginning in month 4 and continuing through month 12. In longitudinal regression modeling, prenatal zinc was associated with greater weight (by 0.58 +/- 0.12 kg; P < 0.001), calf circumference (by 1.01 +/- 0.21 cm; P < 0.001), chest circumference (by 0.60 +/- 0.20 cm; P = 0.002), and calf muscle area (by 35.78 +/- 14.75 mm(2); P = 0.01) after adjustment for a range of covariates. No effect was observed for linear growth.

CONCLUSION

Maternal zinc supplementation in this population was associated with offspring growth, which is suggestive of lean tissue mass accretion.