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.
PIP: Researchers analyzed data collected by the Nutritional Surveillance Project during 1990-94 on children aged 6-59 months living in slum areas of Dhaka, Chittagong, and Khulna and in rural villages to evaluate the role of the universal biannual vitamin A capsule (VAC) distribution program in preventing vitamin A deficiency in Bangladesh. The mean VAC coverage rate was 48.7% in rural areas (compared to 45% in 1982-1983) and 93.7% in the urban slums. There were considerable differences in regional VAC coverage rates in rural areas. If Bangladesh could focus only on VAC distribution in areas with low coverage, countrywide VAC coverage could increase to 70% and VAC distribution efficiency could improve. VAC distribution efficiency was greater in the urban slums than in rural areas (77.8% vs. 27%). The mean prevalence of night blindness in rural areas stood at 0.86% (compared to 3.6% in 1982-1983) and the bimonthly prevalence varied from 0.5% to 1.48%. The corresponding figures for urban areas were 0.22% and 0-0.62%. When the researchers adjusted for many potentially confounding factors, VAC use by individual children diminished the risk of night blindness (rural areas, odds ratio [OR] = 0.74; urban slums, OR = 0.39). Night blindness was more common among malnourished children (e.g., wasting, 0.84-1.31% vs. 0.71-0.94%), and the efficiency of VAC supplementation was somewhat higher among malnourished children (wasting, OR = 0.64 vs. 0.75). Breast feeding protected against night blindness (rural areas, OR = 0.53; urban slums, OR = 0.32). Among urban children who ingested a VAC within the last 6 months, the prevalence of night blindness was inversely associated with the percentage of VAC use within the last 2 months. This suggests that the biologic effect of VAC falls over time and that it does not persist for a full 6 months. Night blindness occurred in children of all socioeconomic levels. In the short term, the VAC distribution program is the most effective strategy to reduce night blindness. Medium and long term strategies may include food fortification, diet modification, and home gardening.