Childhood mortality after a high dose of vitamin A in a high risk population

Effects of primary or secondary prevention with vitamin A supplementation on clinically important outcomes: a systematic review of randomised clinical trials with meta-analysis and trial sequential analysis

OBJECTIVES

This systematic review with meta-analyses of randomised trials evaluated the preventive effects of vitamin A supplements versus placebo or no intervention on clinically important outcomes, in people of any age.

METHODS

We searched different electronic databases and other resources for randomised clinical trials that had compared vitamin A supplements versus placebo or no intervention (last search 16 April 2024). We used Cochrane methodology. We used the random-effects model to calculate risk ratios (RRs), with 95% CIs. We analysed individually and cluster randomised trials separately. Our primary outcomes were mortality, adverse events and quality of life. We assessed risks of bias in the trials and used Grading of Recommendations, Assessment, Development, and Evaluations (GRADE) to assess the certainty of the evidence.

RESULTS

We included 120 randomised trials (1 671 672 participants); 105 trials allocated individuals and 15 allocated clusters. 92 trials included children (78 individually; 14 cluster randomised) and 28 adults (27 individually; 1 cluster randomised). 14/105 individually randomised trials (13%) and none of the cluster randomised trials were at overall low risk of bias. Vitamin A did not reduce mortality in individually randomised trials (RR 0.99, 95% CI 0.93 to 1.05; I²=32%; p=0.19; 105 trials; moderate certainty), and this effect was not affected by the risk of bias. In individually randomised trials, vitamin A had no effect on mortality in children (RR 0.96, 95% CI 0.88 to 1.04; I²=24%; p=0.28; 78 trials, 178 094 participants) nor in adults (RR 1.04, 95% CI 0.97 to 1.13; I²=24%; p=0.27; 27 trials, 61 880 participants). Vitamin A reduced mortality in the cluster randomised trials (0.84, 95% CI 0.76 to 0.93; I²=66%; p=0.0008; 15 trials, 14 in children and 1 in adults; 364 343 participants; very low certainty). No trial reported serious adverse events or quality of life. Vitamin A slightly increased bulging fontanelle of neonates and infants. We are uncertain whether vitamin A influences blindness under the conditions examined.

CONCLUSIONS

Based on moderate certainty of evidence, vitamin A had no effect on mortality in the individually randomised trials. Very low certainty evidence obtained from cluster randomised trials suggested a beneficial effect of vitamin A on mortality. If preventive vitamin A programmes are to be continued, supporting evidence should come from randomised trials allocating individuals and assessing patient-meaningful outcomes.

PROSPERO REGISTRATION NUMBER

CRD42018104347.

Is routine Vitamin A supplementation still justified for children in Nepal? Trial synthesis findings applied to Nepal national mortality estimates

BACKGROUND

The World Health Organization has recommended Vitamin A supplementation for children in low- and middle-income countries for many years to reduce child mortality. Nepal still practices routine Vitamin A supplementation. We examined the potential current impact of these programs using national data in Nepal combined with an update of the mortality effect estimate from a meta-analysis of randomized controlled trials.

METHODS

We used the 2017 Cochrane review as a template for an updated meta-analysis. We conducted fresh searches, re-applied the inclusion criteria, re-extracted the data for mortality and constructed a summary of findings table using GRADE. We applied the best estimate of the effect obtained from the trials to the national statistics of the country to estimate the impact of supplementation on under-five mortality in Nepal.

RESULTS

The effect estimates from well-concealed trials gave a 9% reduction in mortality (Risk Ratio: 0.91, 95% CI 0.85 to 0.97, 6 trials; 1,046,829 participants; low certainty evidence). The funnel plot suggested publication bias, and a meta-analysis of trials published since 2000 gave a smaller effect estimate (Risk Ratio: 0.96, 95% CI 0.89 to 1.03, 2 trials, 1,007,587 participants), with the DEVTA trial contributing 55.1 per cent to this estimate. Applying the estimate from well-concealed trials to Nepal's under-five mortality rate, there may be a reduction in mortality, and this is small from 28 to 25 per 1000 live births; 3 fewer deaths (95% CI 1 to 4 fewer) for every 1000 children supplemented.

CONCLUSIONS

Vitamin A supplementation may only result in a quantitatively unimportant reduction in child mortality. Stopping blanket supplementation seems reasonable given these data.

Vitamin A supplementation for preventing morbidity and mortality in children from six months to five years of age

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.

To see, hear, and live: 25 years of the vitamin A programme in Nepal

Nepal has a rich history of vitamin A research and a national, biannual preschool vitamin A supplementation (VAS) programme that has sustained high coverage for 25 years despite many challenges, including conflict. Key elements of programme success have included (a) evidence of a 26–30% reduction in child mortality from two, in‐country randomized trials; (b) strong political and donor support; (c) positioning local female community health volunteers as key operatives; (d) nationwide community mobilization and demand creation for the programme; and (e) gradual expansion of the programme over a period of several years, conducting and integrating delivery research, and monitoring to allow new approaches to be tested and adapted to available resources. The VAS network has served as a platform for delivering other services, including anthelmintic treatment and screening for acute malnutrition. We estimate that VAS has saved over 45,000 young lives over the past 15 years of attained national coverage. Consumption of vitamin A‐ and carotenoid‐rich foods by children and women nationally remains low, indicating that supplementation is still needed. Current challenges and opportunities to improving vitamin A status include lower VAS coverage among younger children (infants 6–11 months of age), finding ways to increase availability and access to dietary vitamin A sources, and ensuring local programme investments given the recent decentralization of the government.

Vitamin A Deficiency Disorders in Children and Women

Vitamin A deficiency is an endemic nutrition problem throughout much of the developing world, especially affecting the health and survival of infants, young children, and pregnant and lactating women. These age and life-stage groups represent periods when both nutrition stress is high and diet likely to be chronically deficient in vitamin A. Approximately 127 million preschool-aged children and 7 million pregnant women are vitamin A deficient. Health consequences of vitamin A deficiency include mild to severe systemic effects on innate and acquired mechanisms of host resistance to infection and growth, increased burden of infectious morbidity, mild to severe (blinding) stages of xerophthalmia, and increased risk of mortality. These consequences are defined as vitamin A deficiency disorders (VADD). Globally, 4.4 million preschool children have xerophthalmia and 6 million mothers suffer night blindness during pregnancy. Both conditions are associated with increased risk of morbidity and mortality. While reductions of child mortality of 19–54% following vitamin A treatment have been widely reported, more recent work suggests that dosing newborns with vitamin A may, in some settings, lower infant mortality. Among women, one large trial has so far reported a ≥ 40% reduction in mortality related to pregnancy with weekly, low-dose vitamin A supplementation. Epidemiologic data on vitamin A deficiency disorders can be useful in planning, designing, and targeting interventions.

Mortality Benefits of Vitamin A Are Not Affected by Varying Frequency, Total Dose, or Duration of Supplementation

BACKGROUND

Although vitamin A supplementation reduces child mortality, it remains unclear whether dosing frequency, total dose, or duration modifies effectiveness.

OBJECTIVE

Determine whether mortality effects of vitamin A vary by dosing frequency, total dose, or duration.

METHODS

Meta-analysis of randomized controlled trials, identified by systematic review and expert opinion, utilizing relatively standard World Health Organization doses in children <5 years. Meta-regression evaluated whether mortality effects varied by dosing frequency, total dose, or supplementation duration.

RESULTS

Identified 17 trials, including 1,180,718 children, mean (standard deviation [SD]) age 31.5 (15.4) months at baseline. Supplementation frequency ranged every 3 months-every 2 years, supplementation duration 4-60 months (mean = 15.4; SD = 12.8), and total dose 134,361-2,200,000 IU (mean = 667,132 IU; SD = 540,795). Compared with control, vitamin A reduced mortality 22% (95% confidence interval [CI] = 10-32; P = 0.002). This protective effect was not modified by increasing supplementation frequency (dose/year: relative risk [RR] = 1.02; 95% CI = 0.98-1.06; P = .22), total dose (per 200,000 IU: RR = 1.02; 95% CI = 0.97-1.06; P = .31), nor supplementation duration (per year: RR = 1.06; 95% CI = 0.97-1.15; P = 0.14). Multivariate meta-regression showed similar results. Sensitivity analyses excluding 1 controversial trial (Aswathi 2013) did not alter findings.

CONCLUSION

Results confirm benefits of vitamin A supplementation in children <5 years in nations with vitamin A deficiency, without influence of frequency, total dose, or dosing duration within ranges evaluated. These findings inform design and efficiency of vitamin A supplementation policies.

Vitamin A supplementation for preventing morbidity and mortality in children from six months to five years of age

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.

Neonatal vitamin A supplementation for the prevention of mortality and morbidity in term neonates in low and middle income countries

BACKGROUND

Vitamin A deficiency is a major public health problem in low and middle income countries. Vitamin A supplementation in children six months of age and older has been found to be beneficial, but no effect of supplementation has been noted for children between one and five months of age. Supplementation during the neonatal period has been suggested to have an impact by increasing body stores in early infancy.

OBJECTIVES

To evaluate the role of vitamin A supplementation for term neonates in low and middle income countries with respect to prevention of mortality and morbidity.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Review Group to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 2), MEDLINE via PubMed (1966 to 13 March 2016), Embase (1980 to 13 March 2016) and the Cumulative Index to Nursing and Allied Health Literature (CINAHL; 1982 to 13 March 2016). We also searched clinical trials databases, conference proceedings and reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials. Also trials with a factorial design.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted study data. We used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to assess the quality of evidence.

MAIN RESULTS

We included 12 trials (168,460 neonates) in this review, with only a few trials reporting disaggregated data for term infants. Therefore, we analysed data and presented estimates for term infants (when specified) and for all infants.Data for term neonates from three studies did not show a statistically significant effect on the risk of infant mortality at six months in the vitamin A group compared with the control group (typical risk ratio (RR) 0.80; 95% confidence interval (CI) 0.54 to 1.18; I² = 63%). Analysis of data for all infants from 11 studies revealed no evidence of a significant reduction in the risk of infant mortality at six months among neonates supplemented with vitamin A compared with control neonates (typical RR 0.98, 95% CI 0.89 to 1.07; I² = 47%). We observed similar results for infant mortality at 12 months of age with no significant effect of vitamin A compared with control (typical RR 1.04, 95% CI 0.94 to 1.15; I² = 47%). Limited data were available for the outcomes of cause-specific mortality and morbidity, vitamin A deficiency, anaemia and adverse events.

AUTHORS' CONCLUSIONS

Given the high burden of death among children younger than five years of age in low and middle income countries, and the fact that mortality in infancy is a major contributory cause, it is critical to obtain sound scientific evidence of the effect of vitamin A supplementation during the neonatal period on infant mortality and morbidity. Evidence provided in this review does not indicate a potential beneficial effect of vitamin A supplementation among neonates at birth in reducing mortality during the first six months or 12 months of life. Given this finding and the absence of a clear indication of the biological mechanism through which vitamin A could affect mortality, along with substantial conflicting findings from individual studies conducted in settings with potentially varying levels of maternal vitamin A deficiency and infant mortality, absence of follow-up studies assessing any long-term impact of a bulging fontanelle after supplementation and the finding of a potentially harmful effect among female infants, additional research is warranted before a decision can be reached regarding policy recommendations for this intervention.

Supplementation of Infants and/Or Their Mothers with Vitamin A during the First Six Months of Life

It has been clearly demonstrated that in endemic areas, improving the vitamin A status of children aged six months to five years can substantially reduce their risk of mortality and severe morbidity. This paper reviews the potential benefits of improving vitamin A status during the first six months of life by either supplementing the infant or indirectly by supplementing the mother, in order to increase the vitamin A content of her breastmilk. This focus is important, since a large proportion of childhood deaths occur before six months of age. Also, whether or not supplementation has a direct benefit during the first six months of life, it could have an indirect benefit later in life if it ensures that the infant enters the second six months of life with improved vitamin A status. It might thus lead to a reduced risk of mortality in later childhood. in particular, this review evaluates the evidence concerning the health benefits.

Vitamin A supplementation for the prevention of morbidity and mortality in infants one to six months of age

BACKGROUND

Vitamin A deficiency is a significant public health problem in low- and middle-income countries. Vitamin A supplementation provided to infants less than six months of age is one of the strategies to improve the nutrition of infants at high risk of vitamin A deficiency and thus potentially reduce their mortality and morbidity.

OBJECTIVES

To evaluate the effect of synthetic vitamin A supplementation in infants one to six months of age in low- and middle-income countries, irrespective of maternal antenatal or postnatal vitamin A supplementation status, on mortality, morbidity and adverse effects.

SEARCH METHODS

We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL 2016, Issue 2), MEDLINE via PubMed (1966 to 5 March 2016), Embase (1980 to 5 March 2016) and CINAHL (1982 to 5 March 2016). We also searched clinical trials databases, conference proceedings and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials.

SELECTION CRITERIA

Randomised or quasi-randomised, individually or cluster randomised trials involving synthetic vitamin A supplementation compared to placebo or no intervention provided to infants one to six months of age were eligible.

DATA COLLECTION AND ANALYSIS

Two review authors assessed the studies for eligibility and assessed their risk of bias and collected data on outcomes.

MAIN RESULTS

The review included 12 studies (reported in 22 publications). The included studies assigned 24,846 participants aged one to six months to vitamin A supplementation or control group. There was no effect of vitamin A supplementation for the primary outcome of all-cause mortality based on seven studies that included 21,339 (85%) participants (risk ratio (RR) 1.05, 95% confidence interval (CI) 0.89 to 1.25; I2 = 0%; test for heterogeneity: P = 0.79; quality of evidence: moderate). Also, there was no effect of vitamin A supplementation on mortality or morbidity due to diarrhoea and respiratory tract infection. There was an increased risk of bulging fontanelle within 24 to 72 hours of supplementation in the vitamin A group compared to control (RR 3.10, 95% CI 1.89 to 5.09; I2 = 9%, test for heterogeneity: P = 0.36; quality of evidence: high). There was no reported subsequent increased risk of death, convulsions or irritability in infants who developed bulging fontanelle after vitamin A supplementation, and it resolved in most cases within 72 hours. There was no increased risk of other adverse effects such as vomiting, irritability, diarrhoea, fever and convulsions in the vitamin A supplementation group compared to control. Vitamin A supplementation did not have any statistically significant effect on vitamin A deficiency (RR 0.86, 95% CI 0.70 to 1.06; I2 = 27%; test for heterogeneity: P = 0.25; quality of evidence: moderate).

AUTHORS' CONCLUSIONS

There is no convincing evidence that vitamin A supplementation for infants one to six months of age results in a reduction in infant mortality or morbidity in low- and middle-income countries. There is an increased risk of bulging fontanelle with vitamin A supplementation in this age group; however, there were no reported subsequent complications because of this adverse effect.

Biomarkers of Nutrition for Development (BOND)-Vitamin A Review

The Biomarkers of Nutrition for Development (BOND) project is designed to provide evidence-informed advice to anyone with an interest in the role of nutrition in health. The BOND program provides information with regard to selection, use, and interpretation of biomarkers of nutrient exposure, status, function, and effect, which will be especially useful for readers who want to assess nutrient status. To accomplish this objective, expert panels are recruited to evaluate the literature and to draft comprehensive reports on the current state of the art with regard to specific nutrient biology and available biomarkers for assessing nutritional status at the individual and population levels. Phase I of the BOND project includes the evaluation of biomarkers for 6 nutrients: iodine, folate, zinc, iron, vitamin A, and vitamin B-12. This review of vitamin A is the current article in this series. Although the vitamin was discovered >100 y ago, vitamin A status assessment is not trivial. Serum retinol concentrations are under homeostatic control due in part to vitamin A's use in the body for growth and cellular differentiation and because of its toxic properties at high concentrations. Furthermore, serum retinol concentrations are depressed during infection and inflammation because retinol-binding protein (RBP) is a negative acute-phase reactant, which makes status assessment challenging. Thus, this review describes the clinical and functional indicators related to eye health and biochemical biomarkers of vitamin A status (i.e., serum retinol, RBP, breast-milk retinol, dose-response tests, isotope dilution methodology, and serum retinyl esters). These biomarkers are then related to liver vitamin A concentrations, which are usually considered the gold standard for vitamin A status. With regard to biomarkers, future research questions and gaps in our current understanding as well as limitations of the methods are described.

Vitamin A deficiency impacts the structural segregation of gut microbiota in children with persistent diarrhea

To investigate whether gut microbiota is associated with vitamin A nutritional levels in children with persistent diarrhea, a total of 59 pediatric patients with persistent diarrhea aged 1-12 months were selected from the Department of Gastroenterology at the Children's Hospital of Chongqing Medical University, China. Subjects were hospitalized and divided into VA-deficient (n = 30) and VA-normal (n = 29) groups according to their venous serum retinol levels. Fecal samples from all 59 subjects were collected immediately after admission and analyzed by Illumina MiSeq for 16S rRNA genes to characterize the overall microbiota of the samples. The gut microbiota of the VA-deficient and VA-normal groups were compared using a bioinformatic statistical approach. The Shannon index (p = 0.02), Simpson index (p = 0.01) and component diagram data indicated significantly lower diversity in the VA-deficient than the VA-normal group. A metagenome analysis (LEfSe) and a differentially abundant features approach using Metastats revealed that Escherichia coli and Clostridium butyricum were the key phylotypes of the VA-normal group, while Enterococcus predominated the VA-deficient group. In conclusion, the diversity of gut microbiota and the key phylotypes are significantly different in children with persistent diarrhea at different VA nutritional levels.

Meta-analyses involving cluster randomization trials: a review of published literature in health care

Throughout the 1980s and 1990s cluster randomization trials have been increasingly used to evaluate effectivenessof health care intervention. Such trials have raised several methodologic challenges in analysis. Meta-analyses involving cluster randomization trials are becoming common in the area of health care intervention. However, as yet there has been no empirical evidence of current practice in the meta-analyses. Thus a review was performed to identify and examine synthesis approaches of meta-analyses involving cluster randomization trials in the published literature. Electronic databases were searched for meta-analyses involving cluster randomization trials from the earliest date available to 2000. Once a meta-analysis was identified, papers on the relevant cluster randomization trials included were also requested. Each of the original papers of cluster randomization trials included was examined for its randomized design and unit, and adjustment for clustering effect in analysis. Each of the selected meta-analyses was then evaluated as to its synthesis concerning clustering effect. In total, 25 eligible meta-analyses were reviewed. Of these, 15 meta-analyses reported simple conventional methods of the fixed-effect model as method of analysis, while six did not incorporate the cluster randomization trial results in the synthesis methods but described the trial results individually. Three meta-analyses attempted to account for the clustering effect in the synthesis methods but approaches were in arbitrary. Fifteen meta-analyses included more than one cluster randomization trial, each of which included cluster randomization trials with a mixture of randomized designs and units, and units of analysis. These mixture situations might increase heterogeneity, but have not been considered in any meta-analysis. Some methods dealing with a binary outcome for some specific situations have been discussed. In conclusion, some difficulties in the quantitative synthesis procedures were found in the meta-analyses involving cluster randomization trials. Recommendations in the applications of approaches to some specific situations in a binary outcome variable have also been provided. There are still, however, several methodologic issues of the meta-analyses involving cluster randomization trials that need to be investigated further.

An enigma: why vitamin A supplementation does not always reduce mortality even though vitamin A deficiency is associated with increased mortality

BACKGROUND

Vitamin A deficiency (VAD) is associated with increased mortality. To prevent VAD, WHO recommends high-dose vitamin A supplementation (VAS) every 4-6 months for children aged between 6 months and 5 years of age in countries at risk of VAD. The policy is based on randomized clinical trials (RCTs) conducted in the late 1980s and early 1990s. Recent RCTs indicate that the policy may have ceased to be beneficial. In addition, RCTs attempting to extend the benefits to younger children have yielded conflicting results. Stratified analyses suggest that whereas some subgroups benefit more than expected from VAS, other subgroups may experience negative effects.

METHODS AND RESULTS

We reviewed the potential modifiers of the effect of VAS. The variable effect of VAS was not explained by underlying differences in VAD. Rather, the effect may depend on the sex of the child, the vaccine status and previous supplementation with vitamin A. Vitamin A is known to affect the Th1/Th2 balance and, in addition, recent evidence suggests that vitamin A may also induce epigenetic changes leading to down-regulation of the innate immune response. Thus VAS protects against VAD but has also important and long-lasting immunological effects, and the effect of providing VAS may vary depending on the state of the immune system.

CONCLUSIONS

To design optimal VAS programmes which target those who benefit and avoid those harmed, more studies are needed. Work is ongoing to define whether neonatal VAS should be considered in subgroups. In the most recent RCT in older children, VAS doubled the mortality for males but halved mortality for females. Hence, we urgently need to re-assess the effect of VAS on older children in large-scale RCTs powered to study effect modification by sex and other potential effect modifiers, and with nested immunological studies.

Heterologous and sex differential effects of administering vitamin A supplementation with vaccines

WHO recommends high-dose vitamin A supplementation (VAS) to children from 6 months to 5 years of age in low-income countries, in order to prevent and treat vitamin A deficiency-associated morbidity and mortality. The current policy does not discriminate this recommendation either by sex or vaccination status of the child. There is accumulating evidence that the effects of VAS on morbidity, mortality and immunological parameters depend on concomitant vaccination status. Moreover, these interactions may manifest differently in males and females. Certain vaccines administered through the Expanded Program on Immunization have been shown to alter all-cause mortality from infections other than the vaccine-targeted disease. This review summarizes the evidence from observational studies and randomized-controlled trials of the effects of VAS on these so-called heterologous or non-specific effects of vaccines, with a focus on sex differences. In general, VAS seems to enhance the heterologous effects of vaccines, particularly for diphtheria-tetanus-pertussis and live measles vaccines, where some studies, although not unanimously, show a stronger interaction between VAS and vaccination in females. We suggest that vaccination status and sex should be considered when evaluating the effects of VAS in early life.

Review of the safety and efficacy of vitamin A supplementation in the treatment of children with severe acute malnutrition

Background

World Health Organization (WHO) guidelines recommend for children with severe acute malnutrition (SAM), high-dose vitamin A (VA) supplements be given on day 1 of admission, and on days 2 and 14 in the case of clinical signs of vitamin A deficiency (VAD). Daily low-dose VA follows, delivered in a premix added to F-75 and F-100. This study aimed to systematically review the evidence for safety and effectiveness of high-dose VA supplementation (VAS) in treatment of children with SAM.

Methods

A comprehensive literature review was undertaken for all relevant randomized controlled trials (RCT) and observational studies from 1950 to 2012. Studies identified for full review were evaluated using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodology using a set of pre-defined criteria: indirectness; inconsistency; imprecision; and study limitations. A quality rating of high, moderate, or low was then assigned to each study, and only those attaining moderate to high were considered in making recommendations.

Results

Of the 2072 abstracts screened, 38 met criteria for full review, and 20 were rated moderate to high quality. Only one study replicated the WHO VA protocol in children with SAM. Indirectness was a critical limitation, as studies were not exclusive to children with SAM. There was inconsistency across trials for definitions of malnutrition, morbidities, and ages studied; and imprecision arising from sub-group analyses and small sample sizes. Evidence showed improved outcomes associated with low-dose compared to high-dose VAS, except in cases presenting with signs of VAD, measles, and severe diarrhea or shigellosis. Adverse outcomes related to respiratory infection, diarrhea, and growth were associated with high-dose VAS in children who were predominantly adequately nourished. No adverse effects of the high dose were found in children with SAM in the trial that replicated the WHO VA guideline.

Conclusion

This is the first systematic review of the safety and efficacy of high-dose VAS in treatment of SAM. We recommend a low-dose VAS regimen for children with SAM, except in cases presenting with measles, severe diarrhea (shigellosis), and any indication of VAD. Further research is needed in exclusively malnourished children and to explore alternate delivery strategies.

Vitamin A supplementation every 6 months with retinol in 1 million pre-school children in north India: DEVTA, a cluster-randomised trial

BACKGROUND

In north India, vitamin A deficiency (retinol <0·70 μmol/L) is common in pre-school children and 2-3% die at ages 1·0-6·0 years. We aimed to assess whether periodic vitamin A supplementation could reduce this mortality.

METHODS

Participants in this cluster-randomised trial were pre-school children in the defined catchment areas of 8338 state-staffed village child-care centres (under-5 population 1 million) in 72 administrative blocks. Groups of four neighbouring blocks (clusters) were cluster-randomly allocated in Oxford, UK, between 6-monthly vitamin A (retinol capsule of 200,000 IU retinyl acetate in oil, to be cut and dripped into the child's mouth every 6 months), albendazole (400 mg tablet every 6 months), both, or neither (open control). Analyses of retinol effects are by block (36 vs 36 clusters). The study spanned 5 calendar years, with 11 6-monthly mass-treatment days for all children then aged 6-72 months. Annually, one centre per block was randomly selected and visited by a study team 1-5 months after any trial vitamin A to sample blood (for retinol assay, technically reliable only after mid-study), examine eyes, and interview caregivers. Separately, all 8338 centres were visited every 6 months to monitor pre-school deaths (100,000 visits, 25,000 deaths at ages 1·0-6·0 years [the primary outcome]). This trial is registered at ClinicalTrials.gov, NCT00222547.

FINDINGS

Estimated compliance with 6-monthly retinol supplements was 86%. Among 2581 versus 2584 children surveyed during the second half of the study, mean plasma retinol was one-sixth higher (0·72 [SE 0·01] vs 0·62 [0·01] μmol/L, increase 0·10 [SE 0·01] μmol/L) and the prevalence of severe deficiency was halved (retinol <0·35 μmol/L 6%vs 13%, decrease 7% [SE 1%]), as was that of Bitot's spots (1·4%vs 3·5%, decrease 2·1% [SE 0·7%]). Comparing the 36 retinol-allocated versus 36 control blocks in analyses of the primary outcome, deaths per child-care centre at ages 1·0-6·0 years during the 5-year study were 3·01 retinol versus 3·15 control (absolute reduction 0·14 [SE 0·11], mortality ratio 0·96, 95% CI 0·89-1·03, p=0·22), suggesting absolute risks of death between ages 1·0 and 6·0 years of approximately 2·5% retinol versus 2·6% control. No specific cause of death was significantly affected.

INTERPRETATION

DEVTA contradicts the expectation from other trials that vitamin A supplementation would reduce child mortality by 20-30%, but cannot rule out some more modest effect. Meta-analysis of DEVTA plus eight previous randomised trials of supplementation (in various different populations) yielded a weighted average mortality reduction of 11% (95% CI 5-16, p=0·00015), reliably contradicting the hypothesis of no effect.

FUNDING

UK Medical Research Council, USAID, World Bank (vitamin A donated by Roche).

An evidence-based systematic review of vitamin A by the natural standard research collaboration

An evidence-based systematic review of vitamin A by the Natural Standard Research Collaboration consolidates the safety and efficacy data available in the scientific literature using a validated and reproducible grading rationale. This paper includes written and statistical analysis of clinical trials, plus a compilation of expert opinion, folkloric precedent, history, pharmacology, kinetics/dynamics, interactions, adverse effects, toxicology, and dosing.

The historical evolution of thought regarding multiple micronutrient nutrition

Multiple micronutrient nutrition is an idea that originated in the 1940s and exemplifies the iterative nutritional paradigm. In the first four decades of the 20th century, scientists sought to separate and characterize the vitamins that were responsible for xerophthalmia, rickets, pellagra, scurvy, and beriberi. The dietary requirements of the different micronutrients began to be established in the early 1940s. Surveys showed that multiple micronutrient deficiencies were widespread in industrialized countries, and the problem was addressed by use of cod-liver oil, iodized salt, fortified margarine, and flour fortification with multiple micronutrients, and, with rising living standards, the increased availability and consumption of animal source foods. After World War II, surveys showed that multiple micronutrient deficiencies were widespread in developing countries. Approaches to the elimination of multiple micronutrient deficiencies include periodic vitamin A supplementation, iodized salt, targeted iron/folate supplementation, fortified flour, other fortified foods, home fortification with micronutrient powders, and homestead food production. The prevention of multiple micronutrient malnutrition is a key factor in achieving the Millennium Development Goals, given the important effects of micronutrients on health and survival.

Neonatal vitamin A supplementation for the prevention of mortality and morbidity in term neonates in developing countries

BACKGROUND

Vitamin A deficiency is a major public health problem in developing countries. Vitamin A supplementation in children greater than six months of age has been found to be beneficial, with no effect of supplementation between one to five months. Supplementation in the neonatal period has been suggested to have an impact by increasing body stores in early infancy.

OBJECTIVES

To evaluate the role of vitamin A supplementation in term neonates in developing countries with respect to the prevention of mortality and morbidity.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, May 2010), EMBASE and MEDLINE (1966 to May 2010) via PubMed.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials. Trials with factorial designs were also included.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted the data.

MAIN RESULTS

Seven trials (51,446 neonates) were included in this review, with only few trials reporting disaggregated data for term infants. Therefore, we analysed data and presented estimates for term infants (where specified) followed by all infants.Data for term neonates from three studies showed a statistically significant effect on the risk of infant mortality at six months in the vitamin A group compared with the control group (typical risk ratio (RR) 0.82; 95% CI 0.68 to 0.99; I(2) 63%). Analysis of data for all infants from five studies showed a 14% reduction in the risk of infant mortality at six months in neonates supplemented with vitamin A compared to control; this reduction was statistically significant (typical RR 0.86; 95% CI 0.77 to 0.97; I(2) 39%). These findings should be interpreted with caution, however, due to the small number of included studies, wide confidence intervals with upper levels close to the null effect and statistical heterogeneity. Vitamin A supplementation failed to show any significant effect on infant mortality at 12 months of age compared to control (typical rate ratio 1.03; 95% CI 0.87 to 1.23; I(2) 49%). Limited data were available for the outcomes of cause-specific mortality and morbidity, vitamin A deficiency, anaemia and adverse events.

AUTHORS' CONCLUSIONS

Considering mortality in early infancy being a major contributory cause of overall child mortality for the under five year old group in developing countries, it is critical to obtain sound scientific evidence of the effect of vitamin A supplementation in neonates. Evidence provided in this review does indicate a potential beneficial effect of supplementing neonates with vitamin A at birth for reducing mortality in the first half of infancy. Considering the absence of a clear indication of the biological mechanism and conflicting findings from individual studies in settings with varying levels of maternal vitamin A deficiency and infant mortality, and given four additional ongoing trials with approximately 100,000 neonates being enrolled, we propose a delay in any policy recommendations for neonatal vitamin A supplementation.

Vitamin A supplements for preventing mortality, illness, and blindness in children aged under 5: systematic review and meta-analysis

OBJECTIVE

To determine if vitamin A supplementation is associated with reductions in mortality and morbidity in children aged 6 months to 5 years.

DESIGN

Systematic review and meta-analysis. Two reviewers independently assessed studies for inclusion. Data were double extracted; discrepancies were resolved by discussion. Meta-analyses were performed for mortality, illness, vision, and side effects.

DATA SOURCES

Cochrane Central Register of Controlled Trials (CENTRAL) in the Cochrane Library, Medline, Embase, Global Health, Latin American and Caribbean Health Sciences, metaRegister of Controlled Trials, and African Index Medicus. Databases were searched to April 2010 without restriction by language or publication status.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Randomised trials of synthetic oral vitamin A supplements in children aged 6 months to 5 years. Studies of children with current illness (such as diarrhoea, measles, and HIV), studies of children in hospital, and studies of food fortification or β carotene were excluded.

RESULTS

43 trials with about 215,633 children were included. Seventeen trials including 194,483 participants reported a 24% reduction in all cause mortality (rate ratio=0.76, 95% confidence interval 0.69 to 0.83). Seven trials reported a 28% reduction in mortality associated with diarrhoea (0.72, 0.57 to 0.91). Vitamin A supplementation was associated with a reduced incidence of diarrhoea (0.85, 0.82 to 0.87) and measles (0.50, 0.37 to 0.67) and a reduced prevalence of vision problems, including night blindness (0.32, 0.21 to 0.50) and xerophthalmia (0.31, 0.22 to 0.45). Three trials reported an increased risk of vomiting within the first 48 hours of supplementation (2.75, 1.81 to 4.19).

CONCLUSIONS

Vitamin A supplementation is associated with large reductions in mortality, morbidity, and vision problems in a range of settings, and these results cannot be explained by bias. Further placebo controlled trials of vitamin A supplementation in children between 6 and 59 months of age are not required. However, there is a need for further studies comparing different doses and delivery mechanisms (for example, fortification). Until other sources are available, vitamin A supplements should be given to all children at risk of deficiency, particularly in low and middle income countries.

Accelerating progress in achieving the millennium development goal for children through community-based approaches

The Millennium Development Goal 4 (MDG4) calls for the reduction in under-five mortality by two-thirds between 1990 and 2015. Only 16 of the 68 countries with 97% of the world's child deaths are on track to achieve this. This paper reviews the current evidence regarding proven interventions for reducing child mortality in high-mortality, resource-poor settings. All of these interventions require implementation within communities rather than implementation confined to only those attending health facilities with strong community participation in order to be effective. The evidence strongly suggests that facility-based interventions require a strong community-based component in order to improve child mortality in the surrounding population. We provide specific information about common community-based approaches used in the implementation of interventions with documented improvements in child mortality. A stronger emphasis on community-based approaches will be needed in order to accelerate progress in reaching MDG4. This report arises from an ongoing review of assessments of the effectiveness of community-based primary health care (CBPHC) in improving child health sponsored by the Working Group on CBPHC of the American Public Health Association.

Impact of vitamin A supplementation on infant and childhood mortality

Introduction

Vitamin A is important for the integrity and regeneration of respiratory and gastrointestinal epithelia and is involved in regulating human immune function. It has been shown previously that vitamin A has a preventive effect on all-cause and disease specific mortality in children under five. The purpose of this paper was to get a point estimate of efficacy of vitamin A supplementation in reducing cause specific mortality by using Child Health Epidemiology Reference Group (CHERG) guidelines.

Methods

A literature search was done on PubMed, Cochrane Library and WHO regional data bases using various free and Mesh terms for vitamin A and mortality. Data were abstracted into standardized forms and quality of studies was assessed according to standardized guidelines. Pooled estimates were generated for preventive effect of vitamin A supplementation on all-cause and disease specific mortality of diarrhea, measles, pneumonia, meningitis and sepsis. We did a subgroup analysis for vitamin A supplementation in neonates, infants 1-6 months and children aged 6-59 months. In this paper we have focused on estimation of efficacy of vitamin A supplementation in children 6-59 months of age. Results for neonatal vitamin A supplementation have been presented, however no recommendations are made as more evidence on it would be available soon.

Results

There were 21 studies evaluating preventive effect of vitamin A supplementation in community settings which reported all-cause mortality. Twelve of these also reported cause specific mortality for diarrhea and pneumonia and six reported measles specific mortality. Combined results from six studies showed that neonatal vitamin A supplementation reduced all-cause mortality by 12 % [Relative risk (RR) 0.88; 95 % confidence interval (CI) 0.79-0.98]. There was no effect of vitamin A supplementation in reducing all-cause mortality in infants 1-6 months of age [RR 1.05; 95 % CI 0.88-1.26]. Pooled results for preventive vitamin A supplementation showed that it reduced all-cause mortality by 25% [RR 0.75; 95 % CI 0.64-0.88] in children 6-59 months of age. Vitamin A supplementation also reduced diarrhea specific mortality by 30% [RR 0.70; 95 % CI 0.58-0.86] in children 6-59 months. This effect has been recommended for inclusion in the Lives Saved Tool. Vitamin A supplementation had no effect on measles [RR 0.71, 95% CI: 0.43-1.16], meningitis [RR 0.73, 95% CI: 0.22-2.48] and pneumonia [RR 0.94, 95% CI: 0.67-1.30] specific mortality.

Conclusion

Preventive vitamin A supplementation reduces all-cause and diarrhea specific mortality in children 6-59 months of age in community settings in developing countries.

Retinoic acid production by intestinal dendritic cells

Subpopulations of dendritic cells (DCs) in the small intestine and its related lymphoid organs can produce retinoic acid (RA) from vitamin A (retinol). Through the RA production, these DCs play a pivotal role in imprinting lymphocytes with gut-homing specificity, and contribute to the development of immune tolerance by enhancing the differentiation of Foxp3(+) regulatory T cells and inhibiting that of inflammatory Th17 cells. The RA-producing capacity in these DCs mostly depends on the expression of retinal dehydrogenase 2 (RALDH2, ALDH1A2). It is likely that the RALDH2 expression is induced in DCs by the microenvironmental factors in the small intestine and its related lymphoid organs. The major factor responsible for the RALDH2 expression appears to be GM-CSF. RA itself is essential for the GM-CSF-induced RALDH2 expression. IL-4 and IL-13 also enhance RALDH2 expression, but are dispensable. Toll-like receptor-mediated signals can also enhance the GM-CSF-induced RALDH2 expression in immature DCs.

Vitamin A supplementation for preventing morbidity and mortality in children from 6 months to 5 years of age

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).

Cost-effectiveness of "golden mustard" for treating vitamin A deficiency in India

BACKGROUND

Vitamin A deficiency (VAD) is an important nutritional problem in India, resulting in an increased risk of severe morbidity and mortality. Periodic, high-dose vitamin A supplementation is the WHO-recommended method to prevent VAD, since a single dose can compensate for reduced dietary intake or increased need over a period of several months. However, in India only 34 percent of targeted children currently receive the two doses per year, and new strategies are urgently needed.

METHODOLOGY

Recent advancements in biotechnology permit alternative strategies for increasing the vitamin A content of common foods. Mustard (Brassica juncea), which is consumed widely in the form of oil by VAD populations, can be genetically modified to express high levels of beta-carotene, a precursor to vitamin A. Using estimates for consumption, we compare predicted costs and benefits of genetically modified (GM) fortification of mustard seed with high-dose vitamin A supplementation and industrial fortification of mustard oil during processing to alleviate VAD by calculating the avertable health burden in terms of disability-adjusted life years (DALY).

PRINCIPAL FINDINGS

We found that all three interventions potentially avert significant numbers of DALYs and deaths. Expanding vitamin A supplementation to all areas was the least costly intervention, at $23-$50 per DALY averted and $1,000-$6,100 per death averted, though cost-effectiveness varied with prevailing health subcenter coverage. GM fortification could avert 5 million-6 million more DALYs and 8,000-46,000 more deaths, mainly because it would benefit the entire population and not just children. However, the costs associated with GM fortification were nearly five times those of supplementation. Industrial fortification was dominated by both GM fortification and supplementation. The cost-effectiveness ratio of each intervention decreased with the prevalence of VAD and was sensitive to the efficacy rate of averted mortality.

CONCLUSIONS

Although supplementation is the least costly intervention, our findings also indicate that GM fortification could reduce the VAD disease burden to a substantially greater degree because of its wider reach. Given the difficulties in expanding supplementation to areas without health subcenters, GM fortification of mustard seed is an attractive alternative, and further exploration of this technology is warranted.

Oral tolerance in neonates: from basics to potential prevention of allergic disease

Oral tolerance refers to the observation that prior feeding of an antigen induces local and systemic immune tolerance to that antigen. Physiologically, this process is probably of central importance for preventing inflammatory responses to the numerous dietary and microbial antigens present in the gut. Defective oral tolerance can lead to gut inflammatory disease, food allergies, and celiac disease. In the last two cases, the diseases develop early in life, stressing the necessity of understanding how oral tolerance is set up in neonates. This article reviews the parameters that have been outlined in adult animal models as necessary for tolerance induction and assesses whether these factors operate in neonates. In addition, we highlight the factors that are specific for this period of life and discuss how they could have an impact on oral tolerance. We pay particular attention to maternal influence on early oral tolerance induction through breast-feeding and outline the major parameters that could be modified to optimize tolerance induction in early life and possibly prevent allergic diseases.

Effect of vitamin A supplementation in women of reproductive age on maternal survival in Ghana (ObaapaVitA): a cluster-randomised, placebo-controlled trial

BACKGROUND

A previous trial in Nepal showed that supplementation with vitamin A or its precursor (betacarotene) in women of reproductive age reduced pregnancy-related mortality by 44% (95% CI 16-63). We assessed the effect of vitamin A supplementation in women in Ghana.

METHODS

ObaapaVitA was a cluster-randomised, double-blind, placebo-controlled trial undertaken in seven districts in Brong Ahafo Region in Ghana. The trial area was divided into 1086 small geographical clusters of compounds with fieldwork areas consisting of four contiguous clusters. All women of reproductive age (15-45 years) who gave informed consent and who planned to remain in the area for at least 3 months were recruited. Participants were randomly assigned by cluster of residence to receive a vitamin A supplement (25 000 IU retinol equivalents) or placebo capsule orally once every week. Randomisation was blocked and based on an independent, computer-generated list of numbers, with two clusters in each fieldwork area allocated to vitamin A supplementation and two to placebo. Capsules were distributed during home visits undertaken every 4 weeks, when data were gathered on pregnancies, births, and deaths. Primary outcomes were pregnancy-related mortality and all-cause female mortality. Cause of death was established by verbal post mortems. Analysis was by intention to treat (ITT) with random-effects regression to account for the cluster-randomised design. Adverse events were synonymous with the trial outcomes. This trial is registered with ClinicalTrials.gov, number NCT00211341.

FINDINGS

544 clusters (104 484 women) were randomly assigned to vitamin A supplementation and 542 clusters (103 297 women) were assigned to placebo. The main reason for participant drop out was migration out of the study area. In the ITT analysis, there were 39 601 pregnancies and 138 pregnancy-related deaths in the vitamin A supplementation group (348 deaths per 100 000 pregnancies) compared with 39 234 pregnancies and 148 pregnancy-related deaths in the placebo group (377 per 100 000 pregnancies); adjusted odds ratio 0.92, 95% CI 0.73-1.17; p=0.51. 1326 women died in 292 560 woman-years in the vitamin A supplementation group (453 deaths per 100 000 years) compared with 1298 deaths in 289 310 woman-years in the placebo group (449 per 100 000 years); adjusted rate ratio 1.01, 0.93-1.09; p=0.85.

INTERPRETATION

The body of evidence, although limited, does not support inclusion of vitamin A supplementation for women in either safe motherhood or child survival strategies.

FUNDING

UK Department for International Development, and USAID.

Vitamin A and vitamin B-12 concentrations in relation to mortality and morbidity among children born to HIV-infected women

Vitamin A supplementation starting at 6 months of age is an important child survival intervention; however, not much is known about the association between vitamin A status before 6 months and mortality among children born to HIV-infected women. Plasma concentrations of vitamins A and B-12 were available at 6 weeks of age (n = 576 and 529, respectively) for children born to HIV-infected women and they were followed up for morbidity and survival status until 24 months after birth. Children in the highest quartile of vitamin A had a 49% lower risk of death by 24 months of age compared to the lowest quartile (HR: 0.51, 95% CI: 0.29-0.90; P-value for trend = 0.01). Higher vitamin A levels were protective in the sub-groups of HIV-infected and un-infected children but this was statistically significant only in the HIV-uninfected subgroup. Higher vitamin A concentrations in plasma are protective against mortality in children born to HIV-infected women.

Does vitamin A supplementation interact with routine vaccinations? An analysis of the Ghana Vitamin A Supplementation Trial

BACKGROUND

The World Health Organization recommends vitamin A supplementation (VAS) at vaccination contacts after 6 mo of age to reduce mortality. However, it is unknown whether the effect of VAS is independent of vaccinations. One of the original VAS trials from Ghana had collected vaccination information.

OBJECTIVE

We reanalyzed the data to explore the hypothesis that VAS reduces mortality in children who had bacille Calmette-Guérin or measles vaccine as their most recent vaccine but increased mortality when diphtheria-tetanus-pertussis vaccine (DTP) was the most recent vaccine. On the basis of previous studies, we expected the effects to be strongest in girls.

DESIGN

At enrollment, children aged 6-90 mo were randomly assigned to receive VAS or placebo every 4 mo for 2 y. Vaccination status was assessed at enrollment and after 1 and 2 y by reviewing the children's health cards. Lack of a health card was presumed to mean that the child had not been vaccinated.

RESULTS

VAS had a beneficial effect only in children with no record of vaccination at enrollment (n = 5066); the mortality rate ratio (MRR) was 0.64 (95% CI: 0.47, 0.88) compared with 0.95 (95% CI: 0.72, 1.26) in children with one or more vaccinations (n = 6656). Among vaccinated children, the effect of VAS differed between boys (MRR: 0.74; 95% CI: 0.51, 1.08) and girls (MRR: 1.18; 95% CI: 0.84, 1.67) (P = 0.046 for interaction). VAS had a negative effect in measles-vaccinated girls who were missing one or more doses of DTP at enrollment, a group who often received DTP during follow-up (MRR: 2.60; 95% CI: 1.41, 4.80).

CONCLUSIONS

The effect of VAS differed by vaccination status. This is potentially problematic because VAS is provided at vaccination contacts.

Neonatal vitamin A supplementation for prevention of mortality and morbidity in infancy: systematic review of randomised controlled trials

OBJECTIVE

To evaluate the effect of neonatal vitamin A supplementation on infant mortality, morbidity and early adverse effects.

DESIGN

Systematic review, meta-analysis, and meta-regression of randomised controlled trials.

DATA SOURCES

Electronic databases and hand search of reviews; abstracts and proceedings of conferences. Review methods Randomised or quasi-randomised or cluster randomised, placebo controlled trials evaluating the effect of prophylactic, neonatal (<1 month) supplementation with synthetic vitamin A on mortality or morbidity within infancy (<1 year), and early adverse effects (

RESULTS

The six included trials were from developing countries. There was no convincing evidence of a reduced risk of mortality during infancy (relative risk 0.92, 95% confidence interval 0.75 to 1.12, P=0.393 random effect; I(2)=54.1%) or of an increase in early adverse effects including bulging fontanelle (1.16, 0.81 to 1.65, P=0.418; I(2)=65.3%). No variable emerged as a significant predictor of mortality, but data for important risk groups (high maternal night blindness prevalence and low birth weights) were restricted. Limited data (from one to four trials) did not indicate a reduced risk of mortality during the neonatal period (0.90, 0.75 to 1.08, P=0.270; I(2)=0%), cause specific mortality, common morbidities (diarrhoea and others), and admission to hospital. There was, however, evidence of an increased risk of acute respiratory infection and a reduced risk of clinic visits.

CONCLUSIONS

There is no convincing evidence of a reduced risk of mortality and possibly morbidity or of increased early adverse effects after neonatal supplementation with vitamin A. There is thus no justification for initiating such supplementation as a public health intervention in developing countries for reducing infant mortality and morbidity.

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Key Words Collapse

MESH Headings

• Child, Preschool
• Dietary Supplements
• Humans
• Infant
• Infant Mortality
• Perinatal Care
• Randomized Controlled Trials as Topic
• Regression Analysis
• Risk Factors
• Treatment Outcome
• Vitamin A/administration & dosage
• Vitamins/administration & dosage

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Affiliation(s)

Siddhartha Gogia Department of Paediatrics and Clinical Epidemiology, Sitaram Bhartia Institute of Science and Research, B-16 Qutab Institutional Area, New Delhi 110016, India
Harshpal Singh Sachdev

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Retinoic acid production by intestinal dendritic cells and its role in T-cell trafficking

Vitamin A deficiency causes a marked reduction in the number of T and B cells in the small intestinal tissues. The vitamin A metabolite retinoic acid imprints lymphocytes with gut-homing specificity upon antigenic stimulation. In the small intestinal lamina propria, Peyer's patches, and mesenteric lymph nodes, there are dendritic cells capable of producing retinoic acid. Their capacity depends on the expression of retinal dehydrogenases (RALDH). RALDH2, encoded by Aldh1a2, is a major isoform of RALDH in the intestinal dendritic cells under specific pathogen-free conditions, and can be induced by multiple factors constitutively present or induced in the small intestinal microenvironment.

Pediatric ophthalmology in the developing world

PURPOSE OF REVIEW

It is estimated that of the 45 million people who are blind worldwide in 2000, 1.4 million are children from middle-income and low-income countries, the majority of whom live in the poorest regions of Africa and Asia. The focus of this paper is to discuss the status of pediatric ophthalmology in developing countries and the progress that has been made in the areas of avoidable childhood blindness and visual impairment, particularly corneal scarring as a result of vitamin A deficiency, congenital cataract and retinopathy of prematurity. In addition, we will review the prevalence of uncorrected refractive error and discuss the access to pediatric ophthalmologists in developing countries.

RECENT FINDINGS

Some developing countries have begun incorporating vitamin A supplementation and measles immunizations and have seen a decrease in xerophthtalmia. With improvement in vitamin A status, cataract is becoming a more apparent cause of treatable childhood blindness. Amblyopia and uncorrected refractive errors are important and inexpensively treatable causes of visual impairment, with myopia being most common. As neonatal intensive care services in middle-income developing countries improve the survival of premature infants, retinopathy of prematurity is emerging as a significant cause of childhood blindness.

SUMMARY

Childhood blindness and visual impairment in developing countries remains a significant public health issue, but recent initiatives have shown promise of future improvements.

The effect of vitamin A supplementation administered with missing vaccines during national immunization days in Guinea-Bissau

Background WHO recommends high-dose Vitamin A supplementation (VAS) at vaccination contacts after 6 months of age. It has not been studied whether the effect of VAS on mortality depends on the type of vaccine. We have hypothesized that VAS administered with measles vaccine (MV) is more beneficial than VAS with diphtheria–tetanus–pertussis (DTP) vaccine. We assessed the effect of VAS administered with different vaccines during national immunization days (NIDs).

Methods In 2003, VAS was distributed during NIDs in Guinea-Bissau. Children 6 months or older were given VAS, and if they were missing vaccines, these were often given as well. We compared survival between children who had received VAS alone, VAS with DTP or DTP + MV, or VAS with MV. We also compared the survival between participants and non-participants. We followed 6- to 17-month old children until 18 months of age and analysed survival in Cox models.

Results Twenty of 982 VAS-recipients died during follow-up. The mortality rate ratio (MRR) for VAS with DTP + MV or VAS with DTP was 3.43 (1.36–8.61) compared with VAS only. There were no deaths among those who received VAS with MV alone (P = 0.0005 for homogeneity of VAS effects). Children who received VAS with DTP had higher mortality than non-participants who did not receive VAS [MRR = 3.04 (1.31–7.07)].

Conclusion The study design does not allow for definite conclusions. However, the results are compatible with our a priori hypothesis that VAS is more beneficial when given with MV and potentially harmful when given with DTP. Randomized trials testing the impact on mortality of the current WHO policy seem warranted.

Vitamin A for preventing acute lower respiratory tract infections in children up to seven years of age

BACKGROUND

Vitamin A supplements are effective for preventing diarrhoea. There are theoretical reasons it might also be effective for acute lower respiratory tract infections (LRTIs), also very common in children, especially in low income countries.

OBJECTIVES

To assess the effectiveness and safety of vitamin A for preventing acute LRTIs in children up to seven years of age.

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2007, Issue 2); MEDLINE (1966 to July 2007); EMBASE (1974 to July 2007); and the Chinese Biomedicine Database (CBM) (1976 to July 2007).

SELECTION CRITERIA

Randomised controlled trials (RCTs) that assessed the effectiveness of vitamin A in the prevention of acute LRTI in children up to seven years of age.

DATA COLLECTION AND ANALYSIS

The review authors independently extracted data and assessed trial quality. Study authors were contacted for additional information.

MAIN RESULTS

Most studies found no significant effect of vitamin A on the incidence of acute LRTI, or prevalence of symptoms of acute LRTI. Vitamin A caused an increased incidence of acute LRTI in one study; an increase in cough and fever; and increased symptoms of cough and rapid breathing in two others. Three reported no differences and no protective effect of vitamin A. Two studies reported that vitamin A significantly reduced the incidence of acute LRTI with children with poor nutritional status or weight, but increased it in normal children.

AUTHORS' CONCLUSIONS

This unexpected result is outside our current understanding of the use of vitamin A for preventing acute LRTIs. Accordingly, vitamin A should not be given to all children to prevent acute LRTIs. There is evidence for vitamin A supplements to prevent acute LRTIs in children with low serum retinol or those with a poor nutritional status.

Undernutrition, infection and immune function

Undernutrition and infection are the major causes of morbidity and mortality in the developing world. These two problems are interrelated. Undernutrition compromises barrier function, allowing easier access by pathogens, and compromises immune function, decreasing the ability of the host to eliminate pathogens once they enter the body. Thus, malnutrition predisposes to infections. Infections can alter nutritional status mediated by changes in dietary intake, absorption and nutrient requirements and losses of endogenous nutrients. Thus, the presence of infections can contribute to the malnourished state. The global burden of malnutrition and infectious disease is immense, especially amongst children. Childhood infections impair growth and development. There is a role for breast-feeding in protection against infections. Key nutrients required for an efficient immune response include vitamin A, Fe, Zn and Cu. There is some evidence that provision of the first three of these nutrients does improve immune function in undernourished children and can reduce the morbidity and mortality of some infectious diseases including measles, diarrhoeal disease and upper and lower respiratory tract infections. Not all studies, however, show benefit of single nutrient supplementation and this might be because the subjects studied have multiple nutrient deficiencies. The situation regarding Fe supplementation is particularly complex. In addition to immunization programmes and improvement of nutrient status, there are important roles for maternal education, improved hygiene and sanitation and increased supply of quality water in the eradication of infectious diseases.

Newborn vitamin A dosing reduces the case fatality but not incidence of common childhood morbidities in South India

Vitamin A supplementation reduces mortality in young children in areas of endemic vitamin A deficiency. However, it has no impact on the incidence of common morbidities. This discrepancy has been explained by an impact on case fatality, although with the exception of hospitalized measles cases, there is little direct evidence to support this hypothesis. We assessed the impact of newborn dosing with vitamin A on the incidence and case fatality of common childhood morbidities in early infancy in a community-based, randomized trial in South India. Morbidity for each day in the previous 2 wk was assessed for the first 6 mo of life. A total of 11,619 live-born infants were enrolled and randomized to receive either 48,000 IU (50.4 micromol retinol) of oral vitamin A or placebo following delivery. There was no difference between treatment groups in the incidence of acute or chronic diarrhea, dysentery, or fever but a small increased incidence of acute respiratory illness (ARI). Case fatality for diarrhea and fever were significantly reduced in the vitamin A group compared with placebo (relative case fatality [95% CI] of 0.50 [0.27, 0.90] and 0.60 [0.40, 0.88], respectively). There was a trend in reduction of case fatality for various definitions of ARI, but the evidence for this effect was modest. Survival analysis among those with morbid episodes confirmed the case fatality analysis. This trial demonstrated that the reduction in overall mortality due to newborn vitamin A dosing was driven primarily by a reduction in case fatality among infants.

Adjuvant effect of vitamin A on recurrent lower urinary tract infections

BACKGROUND

The purpose of the present paper was to investigate the effects of vitamin A supplementation on recurrent lower urinary tract infections (RUTI).

METHODS

Twenty-four patients with non-complicated RUTI were included in a placebo-controlled, double-blinded study. Twelve patients received a single dose of 200,000 IU vitamin A in addition to antimicrobial therapy. Patient and control groups (each containing 12 patients) were followed for up to 1 year and were evaluated for eradication and frequency of lower urinary tract infections (UTI). Serum levels of vitamin A and beta-carotene were determined periodically.

RESULTS

During the first 6 months follow-up period the infection rate of the vitamin A-supplemented group reduced from 3.58 to 0.75 per 6 months, and in the subsequent 6 months the infection rate was 1.75 per 6 months. These values were calculated as 2.75, 2.83 and 2.66, respectively, in the placebo group.

CONCLUSION

Vitamin A supplementation may have an adjuvant effect on the treatment of RUTI.

Randomized controlled safety and efficacy trial of 2 vitamin A supplementation schedules in Tanzanian infants

BACKGROUND

Vitamin A supplementation reduces morbidity and mortality in children living in areas endemic for vitamin A deficiency. Routine vitamin A supplementation usually starts only at age 9 mo, but high rates of illness and mortality are seen in the first months of life.

OBJECTIVE

The objective of the study was to evaluate the safety and efficacy of vitamin A supplementation at the same time as routine vaccination in infants aged 1-3 mo.

DESIGN

We recruited 780 newborn infants and their mothers to a randomized double-blind controlled trial in Ifakara in southern Tanzania. In one group, mothers received 60,000 microg vitamin A palmitate shortly after delivery, and their infants received 7500 microg at the same time as vaccinations given at approximately 1, 2, and 3 mo of age. In the other group, mothers received a second 60,000-microg dose when their infant was aged 1 mo, and their infants received 15,000 microg at the same time as the routine vaccinations. VAD was defined as a modified relative dose-response test result of >or=0.060.

RESULTS

High-dose vitamin A supplementation was well tolerated. The relative risk of VAD at 6 mo in the high-dose group compared with the lower dose group was 0.91 (95% CI: 0.76, 1.09; P=0.32). Serum retinol and incidence of illness did not differ significantly between the 2 groups. Some vitamin A capsules degraded toward the end of the study.

CONCLUSIONS

Doubling the doses of vitamin A to mothers and their young infants is safe but unlikely to reduce short-term morbidity or to substantially enhance the biochemical vitamin A status of infants at age 6 mo. The stability of vitamin A capsules merits further investigation.

Evaluation of the effectiveness of the national vitamin A supplementation programme among school children in Sri Lanka

The Ministry of Health in Sri Lanka commenced a vitamin A supplementation programme of school children with a megadose of 105 micromol (100,000 IU) vitamin A in school years 1, 4 and 7 (approximately 5-, 9- and 12-year-olds, respectively) in 2001. We evaluated the vitamin A supplementation programme of school children in a rural area of Sri Lanka. A cross-sectional study was conducted among children supplemented with an oral megadose of vitamin A (105 micromol; n 452) and children not supplemented (controls; n 294) in Grades 1-5. Children were clinically examined and a sample of blood was taken for serum vitamin A concentration estimation by HPLC. Socio-demographic information was obtained from children or mothers. Supplemented children had a higher proportion of males and stunted children, were younger and lived under poorer conditions as compared to controls. There was no difference in the prevalences of eye signs and symptoms of vitamin A deficiency in the two groups. Supplemented children had higher serum vitamin A concentrations than controls (1.4 (SD 0.49) micromol/l v. 1.2 (SD 0.52) micromol/l). The serum vitamin A concentrations were 1.6 (SD 0.45), 1.4 (SD 0.50), 1.3 (SD 0.44) and 1.1 (SD 0.43) micromol/l in children supplemented within 1, 1-6, 7-12 and 13-18 months of supplementation, respectively. Vitamin A concentrations were significantly greater than controls if supplementation was carried out within 6 months after adjustment. The oral megadose of 105 micromol vitamin A maintained serum vitamin A concentrations for 6 months in school children.

Vitamin A deficiency disorders in children and women

Vitamin A deficiency is an endemic nutrition problem throughout much of the developing world, especially affecting the health and survival of infants, young children, and pregnant and lactating women. These age and life-stage groups represent periods when both nutrition stress is high and diet likely to be chronically deficient in vitamin A. Approximately 127 million preschool-aged children and 7 million pregnant women are vitamin A deficient. Health consequences of vitamin A deficiency include mild to severe systemic effects on innate and acquired mechanisms of host resistance to infection and growth, increased burden of infectious morbidity, mild to severe (blinding) stages of xerophthalmia, and increased risk of mortality. These consequences are defined as vitamin A deficiency disorders (VADD). Globally, 4.4 million preschool children have xerophthalmia and 6 million mothers suffer night blindness during pregnancy. Both conditions are associated with increased risk of morbidity and mortality. While reductions of child mortality of 19-54% following vitamin A treatment have been widely reported, more recent work suggests that dosing newborns with vitamin A may, in some settings, lower infant mortality. Among women, one large trial has so far reported a > or = 40% reduction in mortality related to pregnancy with weekly, low-dose vitamin A supplementation. Epidemiologic data on vitamin A deficiency disorders can be useful in planning, designing, and targeting interventions.