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.
Keywords: Prediabetes; Prevalence; Type 2 diabetes.