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

This review sought to assess the effects of vitamin A supplementation (VAS) for preventing morbidity and mortality in children aged six months to five years. It was last published in 2017 and was updated in March 2022. 

No new studies are included in the updated version of the review. In the last version, the review authors included 47 studies involving approximately 1,222,856 children. Most studies were conducted in Asia (n = 30; 63%), included equal numbers of boys and girls (mean age 33 months) and lasted about one year. 

Compared with control, the review authors found that VAS reduced the:

  • risk of:
    • all-cause morality by 12% (risk ratio (RR) 0.88, 95% confidence interval (CI) 0.83 to 0.93; 19 studies, 1,202,382; high-certainty evidence);
    • mortality due to diarrhoea by 12% (RR 0.88, 95% CI 0.79 to 0.98; 9 studies, 1,098,538 children; high-certainty evidence); 
    • 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);
  • 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% 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 
    • vitamin A deficiency (RR 0.71, 95% CI 0.65 to 0.78; 4 studies, 2262 children; moderate-certainty evidence).

However, they found no evidence of a difference between VAS and control for:

  • 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, CI% 0.86 to 1.12; 9 studies, 1,098,538 children; low-certainty evidence); and
    • meningitis.
  • the 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 of pneumonia.

As no new studies were included, 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 year would not change the conclusions of the review, but studies that compare different doses and delivery mechanisms are needed. 

Read the full review on the Cochrane Library, here