Subclinical States of Glucose Intolerance and Risk of Death in the U.S.

Abstract

OBJECTIVE—Although clinically evident type 2 diabetes is a well-established cause of mortality, less is known about subclinical states of glucose intolerance. RESEARCH DESIGN AND METHODS—Data from the Second National Health and Nutrition Examination Survey Mortality Study, a prospective study of adults, were analyzed. This analysis focused on a nationally representative sample of 3,174 adults aged 30–75 years who underwent an oral glucose tolerance test at baseline (1976–1980) and who were followed up for death through 1992. RESULTS—Using 1985 World Health Organization criteria, adults were classified as having previously diagnosed diabetes (n = 248), undiagnosed diabetes (n = 183), impaired glucose tolerance (IGT) (n = 480), or normal glucose tolerance (n = 2,263). For these groups, cumulative all-cause mortality through age 70 was 41, 34, 27, and 20%, respectively (P < 0.001). Compared with those with normal glucose tolerance, the multivariate adjusted RR of all-cause mortality was greatest for adults with diagnosed diabetes (RR 2.11, 95% CI 1.56–2.84), followed by those with undiagnosed diabetes (1.77, 1.13–2.75) and those with IGT (1.42, 1.08–1.87; P < 0.001). A similar pattern of risk was observed for cardiovascular disease mortality. CONCLUSIONS—In the U.S., there was a gradient of mortality associated with abnormal glucose tolerance ranging from a 40% greater risk in adults with IGT to a 110% greater risk in adults with clinically evident diabetes. These associations were independent of established cardiovascular disease risk factors.