Trends in the prevalence of type 2 diabetes and prediabetes in community‐dwelling Japanese subjects: The Hisayama Study

AIMS/INTRODUCTION: We examined secular trends in the prevalence of type 2 diabetes and prediabetes in community‐dwelling Japanese subjects. MATERIALS AND METHODS: A total of 2,490 subjects in 1988 and 2,852 subjects in 2002 aged 40–79 years underwent a 75‐g oral glucose tolerance test, and their glucose tolerance status was defined by the 1998 World Health Organization criteria. RESULTS: The age‐adjusted prevalence of type 2 diabetes increased significantly from 1988 to 2002 in men (14.6% in 1988 to 20.8% in 2002, P < 0.001) and women (9.1% in 1988 to 11.2% in 2002, P = 0.002). A significant rise in the age‐adjusted prevalence of prediabetes was also observed in both sexes (26.2% in 1988 to 35.3% in 2002, P < 0.001 for men; 22.5% in 1988 to 25.1% in 2002, P = 0.04 for women). In age‐stratified analysis, the prevalence of type 2 diabetes increased markedly over time in men aged 60–69 and 70–79 years (both P < 0.001) and women aged 70–79 years (P = 0.02). The prevalence of overall and central obesity increased significantly in men aged 60–69 and 70–79 years, and women aged 70–79 years from 1988 to 2002, whereas the frequency of regular exercise decreased significantly in men aged 70–79 years between the surveys. CONCLUSIONS: Our findings suggest that the prevalence of type 2 diabetes and prediabetes increased significantly in both sexes from the 1980s to the 2000s in a general Japanese population, and that the increasing prevalence of obesity and the decline in physical activity exerted an influence on this rising trend.