Self-reported prevalence of non-insulin-dependent diabetes mellitus in the 1st (Issei) and 2nd (Nisei) generation of Japanese-Brazilians over 40 years of age.

The immigration of Japanese people to Brazil began in 1908 with two major waves, from 1925 to 1940 and from 1952 to the 1960s. Brazil has the largest population (about 1,288,000) of Japanese origin outside Japan with varying age groups. A mortality study revealed that diabetes as an underlying cause of death was higher in the first-generation Japanese than in Japan (3.4 vs. 1.9 per 100,000 for men, and 7.2 vs. 1.9 for women). The self-reported prevalences of known diabetes in subjects aged 40 years or older were obtained by questionnaires from three sources. In six Japanese cultural associations in Säo Paulo city, the prevalences were 9.7% and 6.9% for the first generation (mean age 61.5 years) and for the second generation (mean age 40.0 years), respectively. Age-adjusted prevalences, according to the Brazilian population in the 1980 national census, were 6.9% and 8.1% for the first and second generations. According to a study carried out as a part of a socioeconomic census of the Japanese population in Brazil, the prevalences of diabetes were 7.4% and 5.2%, and the age-adjusted prevalences were 5.3% and 5.8% in the first and second generations, respectively. Another study carried out for employees of a bank, owned by Japanese-Brazilian community members, revealed crude prevalences of diabetes in the first and second generations of 7.1% and 4.2%, and age-adjusted prevalences of 7.3% and 8.2%, respectively. These data indicate an increased prevalence of diabetes in this population compared to Japan, suggesting the importance of environmental factors in the pathogenesis of diabetes.