Epidemiological correlates of NIDDM in Hispanics, whites, and blacks in the U.S. population

Characteristics, prevalence, and risk factors for non-insulin-dependent diabetes mellitus (NIDDM) among Hispanics, blacks, and whites aged 20-74 yr in the United States population were investigated with two national surveys that used a household interview to ascertain diagnosed diabetes and a 75-g 2-h oral glucose tolerance test to measure undiagnosed diabetes. The Hispanic Health and Nutrition Examination Survey of 1982-1984 studied Mexican Americans in the southwest U.S., Cuban Americans in the Miami, Florida, area, and Puerto Ricans in the New York City area. The National Health and Nutrition Examination Survey of 1976-1980 examined a national sample of U.S. residents, of whom data on blacks and whites were analyzed. People with diagnosed diabetes in the five populations were similar with respect to mean age (53-57 yr), age at diagnosis (45-48 yr), duration of diabetes (6.9-8.7 yr), and diabetes therapies (58-67% using pharmacological treatment). Mean age of people with undiagnosed diabetes (51-59 yr) was comparable to that of diagnosed cases, and mean fasting (7.1-7.8 mM) and 2-h postchallenge plasma glucose (14.1-15.5 mM) values for people with undiagnosed diabetes were similar among the five populations. However, obesity levels varied by race, sex, and whether diabetes was diagnosed or undiagnosed. Age-standardized prevalence of diabetes (sum of diagnosed and undiagnosed cases) was 6.2% in whites, 9.3% in Cubans, 10.2% in blacks, 13% in Mexican Americans, and 13.4% in Puerto Ricans. Thus, compared to whites, diabetes rates were 50-60% higher among Cubans and blacks and 110-120% higher among Mexican Americans and Puerto Ricans. Age-standardized rates of impaired glucose tolerance were similar among the five populations (10.3-13.8%). Increasing age, obesity, and family history of diabetes were associated with higher rates of diabetes but sex, physical activity, education, income, and acculturation were not risk factors or were only weakly associated with diabetes prevalence.