Abstract
An exploratory assessment was made of the relationship between morbidity during the first six months of life and performance in the Bayley Scales of Mental and Motor Development at eight months of life. The study was conducted in 14 villages of Sui Lin Township, Taiwan, which is a rural agricultural area 180 miles south of Taipei. Prior to the study daily dietary intake of the mothers was estimated to range from 1400 to 2000 kcal and 40 grams of protein. Developmentally the children who were healthy were better off than the children who became ill during the first two trimesters. A striking adverse effect of morbidity was found on both mental and motor scale scores when gastrointestinal and respiratory illness were aggregated. Children without illness plus children who were ill with only one illness in one trimester obtained statistically significantly higher scores than the children who were ill with both types of illness and in both trimesters. These findings were explained as a function of the negative energy balance generally found among ill children in populations where malnutrition is endemic. In search for homeostasis the child reduces activity to decrease energy expenditure, and it is to be expected that the relation of a sick child with its environment may be in jeopardy. A hypothesis regarding the relationship between incidence of morbidity and development is proposed.