[Worsening factors for the progression of impaired glucose tolerance to diabetes mellitus learning from prospective studies].

Although non-insulin-dependent diabetes mellitus (NIDDM) is essentially a genetic disorder, environmental factors after birth including modernization-westernization and its related life style changes play an important role for the development of diabetes. Former prospective studies have indicated high prevalence of diabetes among the subjects with greater impairement of glucose tolerance, family history of diabetes, history of gestational diabetes and obesity. Beside these, more attention has been paid to the elevation of serum fatty acids and food composition as the provocative factors. In some populations, insulin resistance has been suggested to be a major cause of diabetes. In contrast, we have shown that most of the Japanese patients with NIDDM have impaired early insulin response after glucose loading and this should be important as a predictor for NIDDM.