Postchallenge hyperglycemia and mortality in a national sample of U.S. adults.

OBJECTIVE: Although postchallenge hyperglycemia is a well-established feature of type 2 diabetes, its association with risk of mortality is uncertain. Therefore, the aim of this study was to assess the independent association of fasting and 2-h glucose levels with all-cause and cardiovascular disease (CVD) mortality. RESEARCH DESIGN AND METHODS: We analyzed data from the Second National Health and Nutrition Examination Survey (NHANES II) Mortality Study, a prospective cohort study of U.S. adults examined in the NHANES II, and focused on the 3,092 adults aged 30-74 years who underwent an oral glucose tolerance test at baseline (1976-1980). Deaths were identified from U.S. national mortality files from 1976 to 1992. To account for the complex survey design, we used SUDAAN statistical software for weighted analysis. RESULTS: Compared with their normoglycemic counterparts (fasting glucose [FG] < 7.0 and 2-h glucose < 7.8 mmol/l), adults with fasting and postchallenge hyperglycemia (FG > or =7.0 and 2-h glucose > or =11.1 mmol/l) had a twofold higher risk of death after 16 years of follow-up (age- and sex-adjusted relative hazard [RH] 2.1, 95% CI 1.4-3.2). However, adults with isolated postchallenge hyperglycemia (FG < 7.0 and 2-h glucose > or =11.1 mmol/l) were also at higher risk of death (1.6, 1.0-2.6). In proportional hazards analysis, FG (fully adjusted RH 1.10 per 1 SD; 95% CI 1.01, 1.22) and 2-h glucose (1.14, 1.00-1.29) showed nearly identical predictive value for mortality. Similar trends were observed for CVD mortality. CONCLUSIONS: These results suggest that postchallenge hyperglycemia is associated with increased risk of all-cause and CVD mortality independently of other CVD risk factors.

Subclinical states of glucose intolerance and risk of death in the U.S.

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.