Long-term Absolute Risk for Cardiovascular Disease Stratified by Fasting Glucose Level

OBJECTIVE To estimate the long-term absolute risk for cardiovascular disease (CVD) according to fasting glucose (FG) levels below the threshold of diabetes. RESEARCH DESIGN AND METHODS We pooled data from seven observational cohorts of U.S. black and white men and women followed from 1960 to 2015. We categorized FG as follows: <5.0, 5.0-5.5, 5.6-6.2, 6.3-6.9 mmol/L, and diabetes (FG >= 7.0 mmol/L or use of diabetes medications). CVD was defined as fatal/nonfatal coronary heart disease and fatal/nonfatal stroke. We estimated the risk of CVD by FG category at index age 55 years using a modified Kaplan-Meier survival analysis, adjusted for the competing risk of non-CVD death. We also assessed risk for incident CVD according to change in FG before 50 years of age, specifically among the categories <5.6 mmol/L, 5.6-6.9 mmol/L, and diabetes. RESULTS Our sample included 19,630 individuals (6,197 blacks and 11,015 women) without a prior CVD event. Risk for CVD through 85 years of age ranged from 15.3% (<5.0 mmol/L) to 38.6% (diabetes levels) among women and from 21.5% (5.0-5.5 mmol/L) to 47.7% (diabetes levels) among men. An FG of 6.3-6.9 mmol/L was associated with higher long-term CVD risk compared with the lowest FG among men but not women. Increases in glucose during midlife with conversion to diabetes were associated with higher cardiovascular risk (1.3- to 3.6-fold) than increases in glucose below the diabetes threshold. CONCLUSIONS Middle-age individuals with diabetes have high long-term absolute risk for CVD. These data strongly support the importance of blood glucose monitoring in midlife for CVD prevention.