DIABETES AND DIABETES RISK-FACTORS IN 2ND-GENERATION AND 3RD-GENERATION JAPANESE-AMERICANS IN SEATTLE, WASHINGTON

In seattle, Washington, the prevalence of diabetes was 20% in second-g eneration (Nisei) Japanese-American men and 16% in Nisei women 45-74 y ears old, while the prevalence of impaired glucose tolerance (IGT) was 36% in Nisei men and 40% in Nisei women. Hyperglycemia was less and d uration of diabetes shorter in women. Related to diabetes and IGT in N isei were higher fasting plasma insulin levels and central (visceral) adiposity. Prevalence of diabetes was low among the younger (34-53 yea r old) third-generation (sansei) men and women. Among self-reported no n-diabetic Sansei, however, prevalence of IGT was 19% in men and 29% i n women, and IGT was associated with both increased fasting plasma ins ulin levels and more visceral fat, suggesting that many Sansei are at risk of future diabetes. An important lifestyle factor in the developm ent of NIDD in Japanese Americans appeared to be dietary saturated (an imal) fat. Another factor may be physical inactivity. In Japanese-Amer ican women, menopause also appeared to be an important risk factor. Th ese risk factors may be related to fostering the accumulation of visce ral fat and the development of insulin resistance. Five-year follow-up examinations performed in non-diabetic Nisei men and women have yield ed additional information concerning the prognosis of IGT. Of those wo men who were IGT at baseline, 34% were diabetic at follow-up while 17% returned to normal. In men who had been IGT at baseline, 18% were dia betic at follow-up while 36% returned to normal. Over the 5-yr follow- up interval, proportionally more women progressed from normal to IGT ( 54%) then went from IGT to normal (17%). For men, roughly equal propor tions went from normal to IGT (37%) as from IGT to normal (36%). It wo uld therefore appear that greater proportions of Nisei women are progr essing to IGT and to NIDD than are Nisei men. This observation may be related to the increased risk of developing central obesity and insuli n resistance following menopause. Prevalence of cardiovascular disease (hypertension, peripheral vascular disease, and/or coronary heart dis ease) was increased in Japanese Americans with IGT and NIDD. Neuropath y and retinopathy were associated only with NIDD.