Diabetes, asymptomatic hyperglycemia, and 22-year mortality in black and white men - The Chicago Heart Association Detection Project in Industry study

OBJECTIVE - To assess relationships of diabetes and asymptomatic hyperglycemia at baseline to the risk of cardiovascular disease (CVD) and all-cause (ALL) mortality in employed, white and black middle-aged men. RESEARCH DESIGN AND METHODS - A prospective cohort study of 11,554 white men and 666 black men between the ages 35 and 64 from 1967 to 1973 was conducted using data from the Chicago Heart Association (CHA) Detection Project in Industry 22-year mortality follow-up. Cox proportional hazards models, adjusted for age and other CVD risk factors, were used to estimate the relative risk (RR) and the 95% CI of mortality associated with baseline glycemic status. RESULTS - Age-adjusted baseline prevalence of clinical diabetes was similar in white (3.7%) and black (4.3%) men; asymptomatic hyperglycemia (glucose post-50-g load greater than or equal to 11.1 mmol/l) was present in 11.1% of whites and 7.8% of blacks. After controlling for age, lifestyle, and other CVD risk factors, mortality risk was increased among white men with clinical diabetes (CVD: RR 2.51, CI 2.08-3.02; ALL: RR 1.88, CI 1.63-2.17) and asymptomatic hyperglycemia (CVD: RR 1.18, CI 1.01-1.37; ALL: RR 1.24, CI 1.11-1.37), compared with men with postload glucose <8.9 mmol/l. Risks were similarly, though nonsignificantly (owing to low statistical power), increased among black men with clinical diabetes (CVD: RR 1.60, CI 0.60-4.29; ALL: RR 1.78, CI 0.97-3.25) and asymptomatic hyperglycemia (CVD: RR 1.29, CI 0.61-2.72; ALL: RR 1.37, CI 0.85-2.20). CONCLUSIONS - Asymptomatic hyperglycemia and clinical diabetes appear to confer increased mortality risk in both white and black men. In addition, mortality risk is increased with increased severity of glycemia. These findings indicate the importance of applying efforts to reduce risk factors and prevent diabetes in both blacks and whites.