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Imdad A, Rogner J, Sherwani RN, Sidhu J, Regan A, Haykal MR, Tsistinas O, Smith A, Chan XHS, Mayo-Wilson E, Bhutta ZA. Zinc supplementation for preventing mortality, morbidity, and growth failure in children aged 6 months to 12 years. Cochrane Database Syst Rev 2023; 3:CD009384. [PMID: 36994923 PMCID: PMC10061962 DOI: 10.1002/14651858.cd009384.pub3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 03/31/2023]
Abstract
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.
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Affiliation(s)
- Aamer Imdad
- Department of Pediatrics, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Jaimie Rogner
- Departments of Medicine and Pediatrics, University of Rochester Medical Center, Rochester, NY, USA
| | - Rida N Sherwani
- Department of Pediatrics, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Jasleen Sidhu
- Norton College of Medicine, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Allison Regan
- Norton College of Medicine, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Maya R Haykal
- Norton College of Medicine, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Olivia Tsistinas
- Health Sciences Library, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Abigail Smith
- Health Sciences Library, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Xin Hui S Chan
- Pandemic Sciences Institute, University of Oxford, Oxford, UK
| | - Evan Mayo-Wilson
- Department of Epidemiology, UNC Gillings School of Global Public HealthMcGavran-Greenberg Hall, Chapel Hill, NC, USA
| | - Zulfiqar A Bhutta
- Centre for Global Child Health, The Hospital for SickKids, Toronto, Canada
- Center of Excellence for Women and Child Health, Aga Khan University, Karachi, Pakistan
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Imdad A, Mayo-Wilson E, Haykal MR, Regan A, Sidhu J, Smith A, Bhutta ZA. Vitamin A supplementation for preventing morbidity and mortality in children from six months to five years of age. Cochrane Database Syst Rev 2022; 3:CD008524. [PMID: 35294044 PMCID: PMC8925277 DOI: 10.1002/14651858.cd008524.pub4] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
BACKGROUND Vitamin A deficiency (VAD) is a major public health problem in low- and middle-income countries, affecting 190 million children under five years of age and leading to many adverse health consequences, including death. Based on prior evidence and a previous version of this review, the World Health Organization has continued to recommend vitamin A supplementation (VAS) for children aged 6 to 59 months. The last version of this review was published in 2017, and this is an updated version of that review. OBJECTIVES To assess the effects of vitamin A supplementation (VAS) for preventing morbidity and mortality in children aged six months to five years. SEARCH METHODS We searched CENTRAL, MEDLINE, Embase, six other databases, and two trials registers up to March 2021. We also checked reference lists and contacted relevant organisations and researchers to identify additional studies. SELECTION CRITERIA Randomised controlled trials (RCTs) and cluster-RCTs evaluating the effect of synthetic VAS in children aged six months to five years living in the community. We excluded studies involving children in hospital and children with disease or infection. We also excluded studies evaluating the effects of food fortification, consumption of vitamin A rich foods, or beta-carotene supplementation. DATA COLLECTION AND ANALYSIS For this update, two review authors independently assessed studies for inclusion resolving discrepancies by discussion. We performed meta-analyses for outcomes, including all-cause and cause-specific mortality, disease, vision, and side effects. We used the GRADE approach to assess the quality of the evidence. MAIN RESULTS The updated search identified no new RCTs. We identified 47 studies, involving approximately 1,223,856 children. Studies were set in 19 countries: 30 (63%) in Asia, 16 of these in India; 8 (17%) in Africa; 7 (15%) in Latin America, and 2 (4%) in Australia. About one-third of the studies were in urban/periurban settings, and half were in rural settings; the remaining studies did not clearly report settings. Most studies included equal numbers of girls and boys and lasted about one year. The mean age of the children was about 33 months. The included studies were at variable overall risk of bias; however, evidence for the primary outcome was at low risk of bias. A meta-analysis for all-cause mortality included 19 trials (1,202,382 children). At longest follow-up, there was a 12% observed reduction in the risk of all-cause mortality for VAS compared with control using a fixed-effect model (risk ratio (RR) 0.88, 95% confidence interval (CI) 0.83 to 0.93; high-certainty evidence). Nine trials reported mortality due to diarrhoea and showed a 12% overall reduction for VAS (RR 0.88, 95% CI 0.79 to 0.98; 1,098,538 children; high-certainty evidence). There was no evidence of a difference for VAS on mortality due to measles (RR 0.88, 95% CI 0.69 to 1.11; 6 studies, 1,088,261 children; low-certainty evidence), respiratory disease (RR 0.98, 95% CI 0.86 to 1.12; 9 studies, 1,098,538 children; low-certainty evidence), and meningitis. VAS reduced the incidence of diarrhoea (RR 0.85, 95% CI 0.82 to 0.87; 15 studies, 77,946 children; low-certainty evidence), measles (RR 0.50, 95% CI 0.37 to 0.67; 6 studies, 19,566 children; moderate-certainty evidence), Bitot's spots (RR 0.42, 95% CI 0.33 to 0.53; 5 studies, 1,063,278 children; moderate-certainty evidence), night blindness (RR 0.32, 95% CI 0.21 to 0.50; 2 studies, 22,972 children; moderate-certainty evidence), and VAD (RR 0.71, 95% CI 0.65 to 0.78; 4 studies, 2262 children, moderate-certainty evidence). However, there was no evidence of a difference on incidence of respiratory disease (RR 0.99, 95% CI 0.92 to 1.06; 11 studies, 27,540 children; low-certainty evidence) or hospitalisations due to diarrhoea or pneumonia. There was an increased risk of vomiting within the first 48 hours of VAS (RR 1.97, 95% CI 1.44 to 2.69; 4 studies, 10,541 children; moderate-certainty evidence). AUTHORS' CONCLUSIONS This update identified no new eligible studies and the conclusions remain the same. VAS is associated with a clinically meaningful reduction in morbidity and mortality in children. Further placebo-controlled trials of VAS in children between six months and five years of age would not change the conclusions of this review, although studies that compare different doses and delivery mechanisms are needed. In populations with documented VAD, it would be unethical to conduct placebo-controlled trials.
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Affiliation(s)
- Aamer Imdad
- Department of Pediatrics, Division of Pediatric Gastroenterology, Hepatology and Nutrition, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Evan Mayo-Wilson
- Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Maya R Haykal
- College of Medicine, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Allison Regan
- College of Medicine, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Jasleen Sidhu
- College of Medicine, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Abigail Smith
- Health Sciences Library, SUNY Upstate Medical University, Syracuse, New York, USA
| | - Zulfiqar A Bhutta
- Centre for Global Child Health, The Hospital for Sick Children, Toronto, Canada
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Mehata S, Tamang MK, Parajuli KR, Rayamajhee B, Yadav UN, Mehta RK, Singh DR. Serum zinc status is a matter of concern among children and non-pregnant women in a nationwide survey of Nepal. Sci Rep 2021; 11:14904. [PMID: 34290324 PMCID: PMC8295332 DOI: 10.1038/s41598-021-94344-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2021] [Accepted: 07/09/2021] [Indexed: 11/15/2022] Open
Abstract
Nationally representative population data on zinc status in Nepal is lacking at present. This study analyzed data from the recent Nepal National Micronutrient status survey 2016 to determine the prevalence of zinc deficiency and associated risk factors among children aged 6–59 months (n = 1462) and non-pregnant women aged 15–49 years (n = 1923). Venous blood was collected from the participants to measure micronutrients such as zinc, markers of anemia, RBP (vitamin A), and markers of inflammation. Stool samples were collected to assess soil-transmitted helminths and Helicobacter pylori infection. Socio-demographic, household, and other relevant factors were collected by a structured questionnaire. Serum zinc concentration was measured by Microwave Plasma Atomic Emission Spectrometry, and zinc deficiency was defined according to the International Zinc Nutrition Consultative Group’s guidelines. Logistic regression was used to examine the predictors of zinc deficiency among the participants. The overall zinc deficiency in children was 22.9%, while it was higher in non-pregnant women (24.7%). The prevalence of anemia among zinc-deficient children was higher (21.3%) than the zinc non-deficit children (18.7%). The prevalence of anemia was 18% among zinc-deficient non-pregnant women compared to 22% non-deficit non-pregnant women. Predictors associated with zinc deficiency among the study children were living in rural areas (AOR = 2.25, 95% CI, [1.13, 4.49]), the occurrence of diarrhea during the two weeks preceding the survey (AOR = 1.57, 95% CI, [1.07, 2.30]), lowest household wealth quintile (AOR = 0.48, 95% CI, [0.25, 0.92]) and lower vitamin A status (AOR = 0.49, 95% CI, [0.28, 0.85]. The predictors associated with zinc deficiency among non-pregnant women were: being underweight (AOR = 1.55, 95% CI, [1.12, 2.15]), fever occurrence during two weeks preceding the survey (AOR = 1.43, 95% CI, [1.04, 1.98]), H. pylori in the stool (AOR = 1.33, 95% CI, [1.04, 1.71]), lowest household wealth quintile (AOR = 0.62, 95% CI,[0.40, 0.94]) and being at risk of folate deficiency (AOR = 0.58, 95% CI,[0.36, 0.94]). We conclude that community-level intervention programs focused on rural children and women to prevent diarrhea, improve nutrition counseling, and provide economic opportunities in rural communities may help to lower zinc deficiency and other micronutrient deficiencies in the Nepalese population. We believe that intervention programs to address zinc deficiency should not be isolated. Instead, integrated approaches are beneficial to improve overall micronutrient status, such as encouraging dietary diversity, providing livelihood opportunities to the unemployed, micronutrient supplementation to vulnerable populations, and consumption of zinc-rich animal-based foods.
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Affiliation(s)
- Suresh Mehata
- Ministry of Health and Population, Government of Nepal, Kathmandu, Nepal
| | - Man Kumar Tamang
- Center for Research Policy and Implementation, Biratnagar, Nepal. .,Queensland Brain Institute, The University of Queensland, Brisbane, Australia.
| | - Kedar Raj Parajuli
- Nutrition Section, Family Welfare Division, Department of Health Services, Ministry of Health and Population, Kathmandu, Nepal
| | - Binod Rayamajhee
- School of Optometry and Vision Science, Faculty of Health and Medicine, University of New South Wales, Sydney, Australia.,Department of Infection and Immunology, Kathmandu Research Institute for Biological Sciences (KRIBS), Lalitpur, Nepal
| | - Uday Narayan Yadav
- Center for Research Policy and Implementation, Biratnagar, Nepal.,Centre for Primary Health Care and Equity, University of New South Wales, Sydney, Australia.,School of Public Health and Community Medicine, UNSW, Sydney, Australia.,Department of Public Health, Torrens University, Sydney, Australia
| | | | - Dipendra Raman Singh
- Department of Health Services, Ministry of Health and Population, Kathmandu, Nepal
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Zhang YY, Hughes J, Grafenauer S. Got Mylk? The Emerging Role of Australian Plant-Based Milk Alternatives as A Cow's Milk Substitute. Nutrients 2020; 12:E1254. [PMID: 32354190 PMCID: PMC7281999 DOI: 10.3390/nu12051254] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 04/22/2020] [Accepted: 04/26/2020] [Indexed: 12/12/2022] Open
Abstract
Growing ethical, environmental and health concerns have encouraged demand for novel plant-based milk alternatives, yet it remains nebulous whether these products are nutritionally adequate as cow's milk replacements. The aim of this study was to conduct a cross-sectional survey of plant-based milk alternatives available in major Australian supermarkets and selected niche food retailers from November 2019 to January 2020 and assess two dietary scenarios (adolescents and older women) where dairy serves were substituted for plant-based alternatives against Australian Estimated Average Requirements (EAR). We collected compositional data from nutrition panels in juxtaposition with derivatives from the Australian Food Composition database, with a total of 115 products, including tree nuts and seeds (n = 48), legumes (n = 27), coconut (n = 10), grains (n = 19) and mixed sources (n = 10). Just over 50% of products were fortified, but only 1/3 contained similar calcium content to cow's milk. Indiscriminate substitutions might reduce intakes of protein and micronutrients, particularly vitamin A, B2, B12, iodine and zinc, and lead to reductions >50% of the EARs for protein, zinc and calcium in the chosen dietary scenarios. To avoid unintended dietary outcomes, it is vital that consumers make pragmatic decisions regarding dietary replacements for cow's milk.
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Affiliation(s)
- Yianna Y. Zhang
- School of Agriculture and Food, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC 3052, Australia
- CSIRO Agriculture & Food, 671 Sneydes Road, Werribee, VIC 3030, Australia
| | - Jaimee Hughes
- Grains & Legumes Nutrition Council, Mount Street, North Sydney, NSW 2060, Australia
| | - Sara Grafenauer
- Grains & Legumes Nutrition Council, Mount Street, North Sydney, NSW 2060, Australia
- School of Medicine, University of Wollongong, Northfields Avenue, Wollongong, NSW 2522, Australia
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Gera T, Shah D, Sachdev HS. Zinc Supplementation for Promoting Growth in Children Under 5 years of age in Low- and Middle-income Countries: A Systematic Review. Indian Pediatr 2019. [DOI: 10.1007/s13312-019-1537-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Imdad A, Mayo‐Wilson E, Herzer K, Bhutta ZA. Vitamin A supplementation for preventing morbidity and mortality in children from six months to five years of age. Cochrane Database Syst Rev 2017; 3:CD008524. [PMID: 28282701 PMCID: PMC6464706 DOI: 10.1002/14651858.cd008524.pub3] [Citation(s) in RCA: 133] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
BACKGROUND Vitamin A deficiency (VAD) is a major public health problem in low- and middle-income countries, affecting 190 million children under five years of age and leading to many adverse health consequences, including death. Based on prior evidence and a previous version of this review, the World Health Organization has continued to recommend vitamin A supplementation for children aged 6 to 59 months. There are new data available from recently published randomised trials since the previous publication of this review in 2010, and this update incorporates this information and reviews the evidence. OBJECTIVES To assess the effects of vitamin A supplementation (VAS) for preventing morbidity and mortality in children aged six months to five years. SEARCH METHODS In March 2016 we searched CENTRAL, Ovid MEDLINE, Embase, six other databases, and two trials registers. We also checked reference lists and contacted relevant organisations and researchers to identify additional studies. SELECTION CRITERIA Randomised controlled trials (RCTs) and cluster-RCTs evaluating the effect of synthetic VAS in children aged six months to five years living in the community. We excluded studies involving children in hospital and children with disease or infection. We also excluded studies evaluating the effects of food fortification, consumption of vitamin A rich foods, or beta-carotene supplementation. DATA COLLECTION AND ANALYSIS For this update, two reviewers independently assessed studies for inclusion and abstracted data, resolving discrepancies by discussion. We performed meta-analyses for outcomes, including all-cause and cause-specific mortality, disease, vision, and side effects. We used the GRADE approach to assess the quality of the evidence. MAIN RESULTS We identified 47 studies (4 of which are new to this review), involving approximately 1,223,856 children. Studies took place in 19 countries: 30 (63%) in Asia, 16 of these in India; 8 (17%) in Africa; 7 (15%) in Latin America, and 2 (4%) in Australia. About one-third of the studies were in urban/periurban settings, and half were in rural settings; the remaining studies did not clearly report settings. Most of the studies included equal numbers of girls and boys and lasted about a year. The included studies were at variable overall risk of bias; however, evidence for the primary outcome was at low risk of bias. A meta-analysis for all-cause mortality included 19 trials (1,202,382 children). At longest follow-up, there was a 12% observed reduction in the risk of all-cause mortality for vitamin A compared with control using a fixed-effect model (risk ratio (RR) 0.88, 95% confidence interval (CI) 0.83 to 0.93; high-quality evidence). This result was sensitive to choice of model, and a random-effects meta-analysis showed a different summary estimate (24% reduction: RR 0.76, 95% CI 0.66 to 0.88); however, the confidence intervals overlapped with that of the fixed-effect model. Nine trials reported mortality due to diarrhoea and showed a 12% overall reduction for VAS (RR 0.88, 95% CI 0.79 to 0.98; 1,098,538 participants; high-quality evidence). There was no significant effect for VAS on mortality due to measles, respiratory disease, and meningitis. VAS reduced incidence of diarrhoea (RR 0.85, 95% CI 0.82 to 0.87; 15 studies; 77,946 participants; low-quality evidence) and measles (RR 0.50, 95% CI 0.37 to 0.67; 6 studies; 19,566 participants; moderate-quality evidence). However, there was no significant effect on incidence of respiratory disease or hospitalisations due to diarrhoea or pneumonia. There was an increased risk of vomiting within the first 48 hours of VAS (RR 1.97, 95% CI 1.44 to 2.69; 4 studies; 10,541 participants; moderate-quality evidence). AUTHORS' CONCLUSIONS Vitamin A supplementation is associated with a clinically meaningful reduction in morbidity and mortality in children. Therefore, we suggest maintaining the policy of universal supplementation for children under five years of age in populations at risk of VAD. Further placebo-controlled trials of VAS in children between six months and five years of age would not change the conclusions of this review, although studies that compare different doses and delivery mechanisms are needed. In populations with documented vitamin A deficiency, it would be unethical to conduct placebo-controlled trials.
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Affiliation(s)
- Aamer Imdad
- Vanderbilt University School of MedicineDepartment of Pediatrics, D. Brent Polk Division of Gastroenterology, Hepatology and NutritionNashvilleTNUSA37212
| | - Evan Mayo‐Wilson
- Johns Hopkins University Bloomberg School of Public HealthDepartment of Epidemiology615 North Wolfe StreetBaltimoreMarylandUSA21205
| | - Kurt Herzer
- Johns Hopkins School of MedicineTower 711600 North Wolfe St.BaltimoreMDUSA21287
| | - Zulfiqar A Bhutta
- Hospital for Sick ChildrenCentre for Global Child HealthTorontoONCanadaM5G A04
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Bechoff A, Dhuique-Mayer C. Factors influencing micronutrient bioavailability in biofortified crops. Ann N Y Acad Sci 2016; 1390:74-87. [PMID: 28009050 DOI: 10.1111/nyas.13301] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 11/02/2016] [Accepted: 11/07/2016] [Indexed: 01/09/2023]
Abstract
Dietary and human factors have been found to be the major factors influencing the bioavailability of micronutrients, such as provitamin A carotenoid (pVAC), iron, and zinc, in biofortified crops. Dietary factors are related to food matrix structure and composition. Processing can improve pVAC bioavailability by disrupting the food matrix but can also result in carotenoid losses. By degrading antinutrients, such as phytate, processing can also enhance mineral bioavailability. In in vivo interventions, biofortified crops have been shown to be overall efficacious in reducing micronutrient deficiency, with bioconversion factors varying between 2.3:1 and 10.4:1 for trans-β-carotene and amounts of iron and zinc absorbed varying between 0.7 and 1.1 mg/day and 1.1 and 2.1 mg/day, respectively. Micronutrient bioavailability was dependent on the crop type and the presence of fat for pVACs and on antinutrients for minerals. In addition to dietary factors, human factors, such as inflammation and disease, can affect micronutrient status. Understanding the interactions between micronutrients is also essential, for example, the synergic effect of iron and pVACs or the competitive effect of iron and zinc. Future efficacy trials should consider human status and genetic polymorphisms linked to interindividual variations.
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Affiliation(s)
- Aurélie Bechoff
- Natural Resources Institute (NRI), University of Greenwich, Kent, UK
| | - Claudie Dhuique-Mayer
- Department of Persyst-UMR Qualisud, Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD), Montpellier, France
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Abstract
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.
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Affiliation(s)
- Marzia Lazzerini
- Institute for Maternal and Child Health IRCCS Burlo GarofoloWHO Collaborating Centre for Maternal and Child HealthVia dell'Istria 65/1, 34137TriesteItaly
| | - Humphrey Wanzira
- Institute for Maternal and Child Health IRCCS Burlo GarofoloWHO Collaborating Centre for Maternal and Child HealthVia dell'Istria 65/1, 34137TriesteItaly
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Bartelt LA, Sartor RB. Advances in understanding Giardia: determinants and mechanisms of chronic sequelae. F1000PRIME REPORTS 2015; 7:62. [PMID: 26097735 PMCID: PMC4447054 DOI: 10.12703/p7-62] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Giardia lamblia is a flagellated protozoan that is the most common cause of intestinal parasitic infection in children living in resource-limited settings. The pathogenicity of Giardia has been debated since the parasite was first identified, and clinical outcomes vary across studies. Among recent perplexing findings are diametrically opposed associations between Giardia and acute versus persistent diarrhea and a poorly understood potential for long-term sequelae, including impaired child growth and cognitive development. The mechanisms driving these protean clinical outcomes remain elusive, but recent advances suggest that variability in Giardia strains, host nutritional status, the composition of microbiota, co-infecting enteropathogens, host genetically determined mucosal immune responses, and immune modulation by Giardia are all relevant factors influencing disease manifestations after Giardia infection.
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Affiliation(s)
- Luther A. Bartelt
- Division of Infectious Diseases and International Health, University of VirginiaBox 801340, Charlottesville, VA 22908USA
| | - R. Balfour Sartor
- Division of Gastroenterology, Center for Gastrointestinal Biology and Disease, University of North Carolina at Chapel HillCampus Box 7032, Chapel Hill, NC 27599-7032USA
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10
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de Gier B, Mpabanzi L, Vereecken K, van der Werff SD, D'Haese PC, Fiorentino M, Khov K, Perignon M, Chamnan C, Berger J, Parker ME, Díaz RJ, Núñez FA, Rivero LR, Gorbea MB, Doak CM, Ponce MC, Wieringa FT, Polman K. Height, zinc and soil-transmitted helminth infections in schoolchildren: a study in Cuba and Cambodia. Nutrients 2015; 7:3000-10. [PMID: 25903454 PMCID: PMC4425185 DOI: 10.3390/nu7043000] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2015] [Revised: 04/07/2015] [Accepted: 04/09/2015] [Indexed: 11/23/2022] Open
Abstract
Soil-transmitted helminth (STH) infections and zinc deficiency are often found in low- and middle-income countries and are both known to affect child growth. However, studies combining data on zinc and STH are lacking. In two studies in schoolchildren in Cuba and Cambodia, we collected data on height, STH infection and zinc concentration in either plasma (Cambodia) or hair (Cuba). We analyzed whether STH and/or zinc were associated with height for age z-scores and whether STH and zinc were associated. In Cuba, STH prevalence was 8.4%; these were mainly Ascaris lumbricoides and Trichuris trichiura infections. In Cambodia, STH prevalence was 16.8%, mostly caused by hookworm. In Cuban children, STH infection had a strong association with height for age (aB-0.438, p = 0.001), while hair zinc was significantly associated with height for age only in STH uninfected children. In Cambodian children, plasma zinc was associated with height for age (aB-0.033, p = 0.029), but STH infection was not. Only in Cambodia, STH infection showed an association with zinc concentration (aB-0.233, p = 0.051). Factors influencing child growth differ between populations and may depend on prevalences of STH species and zinc deficiency. Further research is needed to elucidate these relationships and their underlying mechanisms.
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Affiliation(s)
- Brechje de Gier
- Department of Health Sciences, VU University Amsterdam, Amsterdam 1081HV, The Netherlands.
| | - Liliane Mpabanzi
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp 2000, Belgium.
| | - Kim Vereecken
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp 2000, Belgium.
| | | | - Patrick C D'Haese
- Laboratory of Pathophysiology, University of Antwerp, Wilrijk, B-2610, Belgium.
| | - Marion Fiorentino
- Institut de Recherche pour le Développement, UMR-204 NutriPass IRD-UM-SupAgro, Montpellier 34394, France.
| | - Kuong Khov
- Department of Fisheries Post-Harvest Technologies and Quality Control, Fisheries Administration, Phnom Penh 12301, Cambodia.
| | - Marlene Perignon
- Institut de Recherche pour le Développement, UMR-204 NutriPass IRD-UM-SupAgro, Montpellier 34394, France.
| | - Chhoun Chamnan
- Department of Fisheries Post-Harvest Technologies and Quality Control, Fisheries Administration, Phnom Penh 12301, Cambodia.
| | - Jacques Berger
- Institut de Recherche pour le Développement, UMR-204 NutriPass IRD-UM-SupAgro, Montpellier 34394, France.
| | | | - Raquel Junco Díaz
- National Institute of Hygiene, Epidemiology and Microbiology, Havana 10300, Cuba.
| | | | | | - Mariano Bonet Gorbea
- National Institute of Hygiene, Epidemiology and Microbiology, Havana 10300, Cuba.
| | - Colleen M Doak
- Department of Health Sciences, VU University Amsterdam, Amsterdam 1081HV, The Netherlands.
| | - Maiza Campos Ponce
- Department of Health Sciences, VU University Amsterdam, Amsterdam 1081HV, The Netherlands.
| | - Frank T Wieringa
- Institut de Recherche pour le Développement, UMR-204 NutriPass IRD-UM-SupAgro, Montpellier 34394, France.
| | - Katja Polman
- Department of Health Sciences, VU University Amsterdam, Amsterdam 1081HV, The Netherlands.
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp 2000, Belgium.
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11
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Mayo-Wilson E, Junior JA, Imdad A, Dean S, Chan XHS, Chan ES, Jaswal A, Bhutta ZA. Zinc supplementation for preventing mortality, morbidity, and growth failure in children aged 6 months to 12 years of age. Cochrane Database Syst Rev 2014:CD009384. [PMID: 24826920 DOI: 10.1002/14651858.cd009384.pub2] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
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.
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Affiliation(s)
- Evan Mayo-Wilson
- Department of Epidemiology, Johns Hopkins University Bloomberg School of Public Health, 615 North Wolfe Street, Baltimore MD, MD, USA, 21205
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12
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Bartelt LA, Roche J, Kolling G, Bolick D, Noronha F, Naylor C, Hoffman P, Warren C, Singer S, Guerrant R. Persistent G. lamblia impairs growth in a murine malnutrition model. J Clin Invest 2013; 123:2672-84. [PMID: 23728173 DOI: 10.1172/jci67294] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Accepted: 03/15/2013] [Indexed: 12/14/2022] Open
Abstract
Giardia lamblia infections are nearly universal among children in low-income countries and are syndemic with the triumvirate of malnutrition, diarrhea, and developmental growth delays. Amidst the morass of early childhood enteropathogen exposures in these populations, G. lamblia–specific associations with persistent diarrhea, cognitive deficits, stunting, and nutrient deficiencies have demonstrated conflicting results, placing endemic pediatric giardiasis in a state of equipoise. Many infections in endemic settings appear to be asymptomatic/ subclinical, further contributing to uncertainty regarding a causal link between G. lamblia infection and developmental delay. We used G. lamblia H3 cyst infection in a weaned mouse model of malnutrition to demonstrate that persistent giardiasis leads to epithelial cell apoptosis and crypt hyperplasia. Infection was associated with a Th2-biased inflammatory response and impaired growth. Malnutrition accentuated the severity of these growth decrements. Faltering malnourished mice exhibited impaired compensatory responses following infection and demonstrated an absence of crypt hyperplasia and subsequently blunted villus architecture. Concomitantly, severe malnutrition prevented increases in B220+ cells in the lamina propria as well as mucosal Il4 and Il5 mRNA in response to infection. These findings add insight into the potential role of G. lamblia as a "stunting" pathogen and suggest that, similarly, malnourished children may be at increased risk of G. lamblia– potentiated growth decrements.
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Affiliation(s)
- Luther A Bartelt
- Division of Infectious Diseases and Center for Global Health, University of Virginia, Charlottesville, Virginia 22903, USA.
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13
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Abstract
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.
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Affiliation(s)
- Marzia Lazzerini
- Unit for Health Services Research and International Health,WHO Collaborating Centre forMaternal and ChildHealth, Institute forMaternal and Child Health, Trieste, Italy.
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14
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Abstract
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.
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Affiliation(s)
- Marzia Lazzerini
- Unit for Health Services Research and International Health,WHO Collaborating Centre forMaternal and ChildHealth, Institute forMaternal and Child Health, Trieste, Italy.
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15
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Imdad A, Herzer K, Mayo-Wilson E, Yakoob MY, Bhutta ZA. Vitamin A supplementation for preventing morbidity and mortality in children from 6 months to 5 years of age. Cochrane Database Syst Rev 2010:CD008524. [PMID: 21154399 DOI: 10.1002/14651858.cd008524.pub2] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND Vitamin A deficiency (VAD) is a major public health problem in low and middle income countries affecting 190 million children under 5. VAD can lead to many adverse health consequences, including death. OBJECTIVES To evaluate the effect of vitamin A supplementation (VAS) for preventing morbidity and mortality in children aged 6 months to 5 years. SEARCH STRATEGY We searched the Cochrane Central Register of Controlled Trials (CENTRAL 2010 Issue 2), MEDLINE (1950 to April Week 2 2010), EMBASE (1980 to 2010 Week 16), Global Health (1973 to March 2010), Latin American and Caribbean Health Sciences (LILACS), metaRegister of Controlled Trials and African Index Medicus (27 April 2010). SELECTION CRITERIA Randomised controlled trials (RCTs) and cluster RCTs evaluating the effect of synthetic VAS in children aged 6 months to 5 years living in the community. We excluded studies concerned with children in hospital and children with disease or infection. We excluded studies evaluating the effects of food fortification, consumption of vitamin A rich foods or beta-carotene supplementation. DATA COLLECTION AND ANALYSIS Two review authors independently assessed studies for inclusion. Data were double abstracted and discrepancies were resolved by discussion. Meta-analyses were performed for outcomes including all-cause and cause-specific mortality, disease, vision, and side-effects. MAIN RESULTS 43 trials involving 215,633 children were included. A meta-analysis for all-cause mortality included 17 trials comprising 194,795 children with 3536 deaths in both groups. At follow-up, there was a 24% observed reduction in the risk of all-cause mortality for Vitamin A compared with Control (Relative risk (RR) = 0.76 [95% confidence interval (CI) 0.69, 0.83]). Seven trials reported diarrhoea mortality and a 28% overall reduction for VAS (RR = 0.72 [0.57, 0.91]). There was no significant effect of VAS on cause specific mortality of measles, respiratory disease and meningitis. VAS reduced incidence of diarrhoea (RR = 0.85 [0.82, 0.87]) and measles morbidity (RR = 0.50 [0.37, 0.67]); however, there was no significant effect on incidence of respiratory disease or hospitalisations due to diarrhoea or pneumonia. There was an increased risk of vomiting within the first 48 hours of VAS (RR = 2.75 [1.81, 4.19]). AUTHORS' CONCLUSIONS VAS is effective in reducing all-cause mortality by about 24% compared to no treatment. In our opinion, given the evidence that VAS causes considerable reduction in child mortality, further placebo-controlled trials of VAS in children between 6 months and 5 years of age are not required. There is a need for further studies comparing different doses and delivery mechanisms (for example, fortification).
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Affiliation(s)
- Aamer Imdad
- Division of Women and Child Health, Aga Khan University Hospital, Stadium Road, PO Box 3500, Karachi, Pakistan, 74800
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16
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Abstract
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.
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Affiliation(s)
- Marzia Lazzerini
- Unit of Research on Health Services and International Health, WHO Collaborating Centre for Maternal and Child Health, Via dei Burlo 1,34123, Trieste, Italy.
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