The prevalence of obesity and thinness in children from a lower socioeconomic population receiving comprehensive health care.

The relative body weights of 1830 children from low-income families ranging in age from 2 months to 18 years were calculated using the weight-for-length index (WLI). The effects of age, sex and race on WLI were tested with a 3-way analysis of variance test. A significant age and race interaction was found for the whole sample, as well as significant age and sex interaction for blacks only. Additional analysis revealed that most of the variance in WLI could be explained by weight variations in black females. When the children were classified as obese, overweight, and thin basedon their WLI scores, black males were found to have the lowest prevalence of obesity followed by slightly higher values for the other groups. When overweight and obese children were combined into one group, black females had the highest prevalence of overweight-obese children followed by white males, black males, and white females. In contrast, white females had the highest prevalence of thinness, followed by white males, black females, and black males. Additional analysis suggested that there are important social and/or environmental factors within this particular socioeconomic group that are interacting with biological processes to influence the prevalence of obesity and thinness within each age group.