The role of universal distribution of vitamin A capsules in combatting vitamin A deficiency in Bangladesh.

Vitamin A deficiency is a major public health problem among preschool-aged children in many developing countries. In Bangladesh, a national nutritional surveillance system was initiated in 1990 to monitor 1) the occurrence of vitamin A deficiency by history of night blindness and 2) the routine coverage of national twice-yearly prophylactic vitamin A capsule (VAC) distribution. This study comprised data collected from June 1990 to August 1994. The VAC distribution had a mean coverage rate of 48.7% (95% confidence interval (CI) 48.4-49.0) in the rural areas; the coverage rate in the urban slums was 93.7% (95% CI 93.4-94.0). In the rural areas, the mean prevalence of night blindness was 0.86% (95% CI 0.81-0.91) and the bimonthly prevalence of night blindness ranged from 0.50% (95% CI 0.32-0.77) to 1.48% (95% CI 1.19-1.85), while in the urban slums the mean prevalence was 0.22% (95% CI 0.18-0.28) and the bimonthly prevalence ranged from zero to 0.62% (95% CI 0.27-1.37). The efficiency of VAC distribution was 27% (95% CI 17.6-35.3) in the rural areas and 77.8% (95% CI 61.8-87.1) in the urban slums. After adjustment for multiple potentially confounding factors, VAC receipt by individual children reduced the risk of night blindness in both rural and urban areas (rural areas: odds ratio (OR) = 0.74, 95% CI 0.63-0.87; urban slums: OR = 0.39, 95% CI 0.19-0.82). Breastfeeding was a protective factor for night blindness in both rural (OR = 0.53, 95% CI 0.42-0.67) and urban (OR = 0.32, 95% CI 0.15-0.66) areas. Night blindness was inversely related to the level of routinely attained coverage, and the degree of protection was associated with the time interval between the moment of VAC receipt and the moment of data collection. Although the prevalence of vitamin A deficiency in Bangladesh has been considerably lower in the 1990s than it was in the 1980s, it is still prevalent at all socioeconomic levels. Supplementation with high-dose VACs is an effective strategy for reducing night blindness, but the efficiency of the program will improve when coverage in the rural areas increases.