The purpose of this study was to determine the association of the prevalence of non-insulin-dependent diabetes (NIDDM) with central obesity, obesity, and family history of diabetes. This survey consisted of 1590 subjects (646 men, 944 women) aged 30 years or more from the Sun-Ming district of Kaoshiung city. Glucose tolerance status was ascertained by both medical history and a 75-g oral glucose tolerance test according to World Health Organization criteria. In men and women with central obesity (WHR > or = 0.92 in men and > or = 0.85 in women) or obesity (BMI > or = 27.6 kg/m2 in men and > or = 28.3 kg/m2 in women) (WHR: waist-hip ratio; BMI: body mass index), the prevalence of impaired glucose tolerance (IGT) and diabetes was significantly higher, except the prevalence of diabetes in both sexes with obesity and the prevalence of IGT in women with central obesity were not statistically different, as compared with nonobese subjects. The prevalence of diabetes in men significantly increased from the first quartile to the fourth quartile of BMI and the waist-hip ratio (WHR) (4.48% to 9.21% in BMI, 3.67% to 13.61% in WHR), while the prevalence in women also significantly increased from the first to fourth quartile (2.45% to 11.76% in BMI, 2.04% to 13.49% in WHR). Multiple logistic regression analyses revealed similar increase in the prevalence of diabetes among both men and women for every 1 kg/m2 increase in BMI and every 0.05 increase in WHR (1.07-fold and 1.09-fold in BMI, 1.34-fold and 1.32-fold in WHR, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)