Seasonal changes in nutritional status and the prevalence of malnutrition in a longitudinal study of young children in rural Bangladesh.

During longitudinal field studies of the growth, dietary intake, and morbidity from infectious diseases of children between 6 and 60 months of age in two rural villages of Bangladesh, seasonal fluctuations in growth, nutritional status, and the prevalence of malnutrition were observed. The weight, length, arm circumference, and triceps skinfold thickness of 197 children were measured monthly for 15 months and compared with sex-specific local village norms and international reference populations. The percentages of expected weight for length, arm circumference for age, triceps skinfold thickness for age, and the percentages of expected monthly increments of weight and length for age were the indicators most sensitive to seasonal changes. The percentages of expected weight for age and length for age also changed significantly by month of year, but were less responsive to seasonal variation. The periods of greatest nutritional deficit depended on which anthrometric indicator was used to define nutritional status, but generally occurred during the monsoon and persisted until the subsequent harvest period. However, the fall in mean percentage of expected length for age and the increase in the prevalence of stunting occurred several months after the periods of greatest malnutrition identified by the other measurements. The importance of selecting the appropriate anthropometric techniques to detect seasonal changes and the implications of such changes are discussed.