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.