Adipocyte size and number were determined in 288 subjects ranging in age from 4 mo to 19 yr. The study was performed in 110 obese and 178 non-obese subjects. 4-yr, longitudinal, follow-up studies were also performed in 132 subjects. The results demonstrate that the contribution of cell number and size to the growth of the fat depot in nonobese children varies with age. Deviations from this normal development were observed in obese children shortly after 1 yr of age. By 11 yr of age obese children exceeded the mean cell number found in nonobese adults. Indeed, obese subjects displayed more rapid and earlier elevations in both cell number and size, which were maintained throughout the study. Thus obese children display both quantitative and qualitative differences in fat tissue development when compared to nonobese children. The data indicate that the rate and type of adipose tissue cellular development one encounters in children may play a role in the development of the enlarged fat depots found in obese subjects.
J L Knittle, K Timmers, F Ginsberg-Fellner, R E Brown, D P Katz