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.

Centre-based day care for children younger than five years of age in low- and middle-income countries

BACKGROUND

Because of poverty, children and families in low- and middle-income countries often face significant impediments to health and well-being. Centre-based day care services may influence the development of children and the economic situation of parents by providing good quality early childhood care and by freeing parents to participate in the labour force.

OBJECTIVES

To assess the effects of centre-based day care without additional interventions (e.g. psychological or medical services, parent training) on the development, health and well-being of children and families in low- and middle-income countries (as defined by the World Bank 2011).

SEARCH METHODS

In April 2014, we searched CENTRAL, Ovid MEDLINE, EMBASE, PsycINFO, ERIC and 16 other sources, including several World Health Organization (WHO) regional databases. We also searched two trials registers, websites of government and non-government agencies and reference lists of relevant studies.

SELECTION CRITERIA

We included randomised and quasi-randomised controlled trials and prospective non-randomised studies with contemporaneous control groups and assessments both before and after intervention. We considered non-randomised controlled trials, as centre-based care in low- and middle-income countries is unlikely to be studied using randomised controlled trials (Higgins 2011). We included the following outcomes: child intellectual development, child psychosocial development, maternal and family outcomes and incidence of infectious diseases.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed risk of bias and extracted data from the single included study.

MAIN RESULTS

Only one trial, involving 256 children, met the inclusion criteria for this review. This study was assessed as having high risk of bias because of non-random allocation, incomplete outcome data and insufficient control of confounding factors. Results from this study suggest that centre-based day care may have a positive effect on child cognitive ability compared with no treatment (care at home) (assessed using a modified version of the British Ability Scale-II (BAS-II) (standardised mean difference (SMD) 0.74, 95% confidence interval (CI) 0.48 to 1.00, 256 participants, 1 study, very low-quality evidence). This study did not measure other variables relevant to this review.

AUTHORS' CONCLUSIONS

The single study included in this review provides limited evidence on the effects of centre-based day care for children younger than five years of age in low- and middle-income countries. This study was at high risk of bias and may have limited generalisability to other low- and middle-income countries. Many of the studies excluded from this review paired day care attendance with co-interventions that are unlikely to be provided in normal day care centres. Effectiveness studies on centre-based day care without these co-interventions are few, and the need for such studies is significant. In future studies, comparisons might include home visits or alternative day care arrangements.

Centre-based day care for children younger than five years of age in high-income countries

BACKGROUND

A large proportion of children younger than five years of age in high-income countries experience significant non-parental care. Centre-based day care services may influence the development of children and the economic situation of parents.

OBJECTIVES

To assess the effects of centre-based day care without additional interventions (e.g. psychological or medical services, parent training) on the development and well-being of children and families in high-income countries (as defined by the World Bank 2011).

SEARCH METHODS

In April 2014, we searched CENTRAL, Ovid MEDLINE, EMBASE, PsycINFO, the Education Resources Information Center (ERIC) and eight other databases. We also searched two trials registers and the reference lists of relevant studies.

SELECTION CRITERIA

We included randomised and quasi-randomised controlled trials of centre-based day care for children younger than five years of age. We excluded studies that involved co-interventions not directed toward children (e.g. parent programmes, home visits, teacher training). We included the following outcomes: child cognitive development (primary outcome), child psychosocial development, maternal and family outcomes and child long-term outcomes.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the risk of bias and extracted data from the single included study. We contacted investigators to obtain missing information.

MAIN RESULTS

We included in the review one trial, involving 120 families and 143 children. Risk of bias was high because of contamination between groups, as 63% of control group participants accessed day care services separate from those offered within the intervention. No evidence suggested that centre-based day care, rather than no treatment (care at home), improved or worsened children's cognitive ability (Griffiths Mental Development Scale, standardised mean difference (SMD) 0.34, 95% confidence interval (CI) -0.01 to 0.69, 127 participants, 1 study, very low-quality evidence) or psychosocial development (parental report of abnormal development, risk ratio (RR) 1.21, 95% CI 0.25 to 5.78, 137 participants, 1 study, very low-quality evidence). No other measures of child intellectual or psychosocial development were reported in the included study. Moreover, no evidence indicated that centre-based day care, rather than no treatment (care at home), improved or worsened employment of parents, as measured by the number of mothers in full-time or part-time employment (RR 1.12, 95% CI 0.85 to 1.48, 114 participants, 1 study, very low-quality evidence) and maternal hours per week in paid employment (SMD 0.20, 95% -0.15 to 0.55, 127 participants, 1 study, very low-quality evidence) or household income above £200 per week (RR 0.86, 95% CI 0.57 to 1.29, 113 participants, 1 study, very low-quality evidence). This study did not report on long-term outcomes for children (high-school completion or income).

AUTHORS' CONCLUSIONS

This review includes one trial that provides inconclusive evidence as regards the effects of centre-based day care for children younger than five years of age and their families in high-income countries. Robust guidance for parents, policymakers and other stakeholders on the effects of day care cannot currently be offered on the basis of evidence from randomised controlled trials. Some trials included co-interventions that are unlikely to be found in normal day care centres. Effectiveness studies of centre-based day care without these co-interventions are few, and the need for such studies is significant. Comparisons might include home visits or alternative day care arrangements that provide special attention to children from low-income families while exploring possible mechanisms of effect.