Adequate vitamin A liver stores estimated by the modified relative dose response test are positively associated with breastfeeding but not vitamin A supplementation in Senegalese urban children 9-23 months old: A comparative cross-sectional study

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.

Prevalence of vitamin A deficiency and dietary inadequacy in Indian school-age children and adolescents

PURPOSE

There are no representative estimates of vitamin A deficiency (VAD) and risk of vitamin A (VA) dietary inadequacy in Indian children and adolescents. To evaluate, from national surveys, the prevalence of VAD measured by serum retinol concentrations (< 0.7 µmol/L or < 20 µg/dL), and the risk of VA dietary inadequacy and excess intake beyond the tolerable upper limit (TUL).

METHODS

National and state-level VAD prevalence adjusted for inflammation was estimated in school-age children (5-9 years: 10,298) and adolescents (10-19 years: 9824) from the Comprehensive National Nutrition Survey (CNNS 2016-18). The risk of dietary inadequacy against age-specific average VA requirements, and excess intake against the TUL, was assessed from the National Sample Survey Office (NSSO 2014) data.

RESULTS

Serum retinol concentrations increased with age (5-19 years) in both genders and were significantly lower in school-age children (1.02 µmol/L, CI: 1.01-1.03) compared to adolescents (1.13 µmol/L, CI 1.12-1.15). The inflammation-adjusted prevalence of VAD in school-age children and adolescents was 19.3% (CI 18.8-19.9) and 14.4% (CI 13.9-14.9) respectively, and this was > 20% in seven and four states for children and adolescents, respectively. The prevalence of VAD was significantly higher among children with lower socio-economic status. The risk of dietary VA inadequacy, from the NSSO survey, was 69 and 78% in children and adolescents, respectively. This risk reduced to 6 and 17% with VA fortified oil and milk intake, while the proportion of intakes exceeding the TUL became 6 and 0.5% in children and adolescents, respectively.

CONCLUSIONS

The national prevalence of VAD in school-age children and adolescents in India was just less than 20%. The risk of dietary VA deficiency is likely to decline substantially with VA fortified food intake, but a risk of excessive intake also begins to appear; therefore, a careful assessment of the risk of hypervitaminosis A is required at these ages.