Adipocytes and adiposity in adults.

Measures of adipocyte size and body density were collected from 217 nonobese adults 20 to 50 yr of age, and estimates of total body fat, percentage body fat, and adipocyte number were calculated. Women had a greater percentage body fat than men in every age group except the oldest. Women had significantly greater amounts of total body fat and larger adipocytes than men in the 20- to 24-yr group, but men had significantly greater amounts of total body fat than the women in the 45- to 50-yr group. Adipocyte number, total body fat, and percentage body fat are each positively correlated with age in both sexes. Adipocyte size is not correlated with age but is positively correlated with total and percent body fat in men and women irrespective of age. These cross-sectional data suggest that adipocyte number, rather than being stable during adulthood, increases with age and is associated with corresponding increases in total and percentage body fat.