Relation between body fat and age in 4 ethnic groups

Background: Previous studies of the relation between age and body far reach ed differing conclusions concerning the question of whether body fat is low er in the elderly than in middle-aged persons. Objective: The objectives of this study were to characterize the relation b etween age and body fat in 4 ethnic groups and test the hypothesis that bod y fat is lower in the elderly than in middle-aged persons. Design: Body fat was measured in a sample of 1324 volunteers aged 20-94 y b y using a 4-component model of body composition. Four ethnic groups were st udied: Asians, blacks, Puerto Ricans, and whites. Regression models were de veloped for fat mass and fat percentage as functions of age. Results: In all but one of the groups, a highly significant curvilinear rel ation between age and body fat was found, indicating a peak amount of body fat in late middle age and lower amounts of body fat at younger and older a ges (P < 0.001). The age at which maximum body fat was predicted in the var ious groups ranged from 53 to 61 y for fat mass and from 55 to 71 y for fat percentage. In Puerto Rican men there was no significant relation between age and fat mass, and the relation between age and fat percentage was linea r and positively correlated. Conclusions:This study provided data on the relation between age and body f at in 4 ethnic groups and supported the hypothesis that body fat is lower i n the elderly than in middle-aged persons.