AbstractObesity in American Samoan adults in 1990 was compared to that in 1976–1978 to evaluate population changes concomitant with modernization. Body weight, stature, the body mass index (BMI), and two skinfolds were measured in 1990 in 830 males and females 25–74 years old, and were compared to corresponding data from 1976 and 1978 for 1,621 adults. Mean BMI and skinfold thicknesses increased markedly from 1976–1978 to 1990 in males at all ages. Mean BMI for 45–54 year old males was approximately 3.6 kg/m2higher (P<0.0001) in 1990 than in 1976–1978, but was only 0.6 kg/m2higher in females of the same age. The prevalence of overweight increased significantly from 66% in 1976–1978 to 85% in 1990 (P<0.001) in 35–44 year old males, but remained about the same, 91%, in females of that age. Similar sex differences in temporal change were found in skinfolds. Fasting serum total and high density lipoprotein (HDL) cholesterol and triglycerides were obtained for a random subsample of 67 males 40–49 years old and were compared to lipid levels in a 1978 sample of American Samoan males of similar age and residence. Both total and HDL cholesterol were significantly different between 1978 and 1990, 178 vs. 205 mg/dl (P<0.02), and 43 vs. 37 mg/dl (P<0.01), respectively. Triglycerides were higher in 1990 than in 1978, 169 vs. 128 mg/dl. The results suggest that obesity and adiposity increased more over 12–14 years among adult males than among females, who in 1976–1978 were already massively overweight. ©