Impact of diabetes on cardiovascular disease risk and all-cause mortality in older men: influence of age at onset, diabetes duration, and established and novel risk factors.

BACKGROUND

We have examined the influence of age at onset and duration on the impact of diabetes mellitus on cardiovascular disease risk and all cause-mortality among men aged 60 to 79 years.

METHODS

A prospective study of 4045 men aged 60 to 79 years followed up for a mean of 9 years, during which there were 372 major coronary heart disease (CHD) events (fatal and nonfatal myocardial infarction [MI]), 455 deaths from cardiovascular disease, and 1112 deaths from all causes. Men were classified as having (1) no history of MI and diabetes, (2) late-onset diabetes (diagnosed at ≥60 years or undiagnosed diabetes [fasting blood glucose level, >126.1 mg/dL]), (3) early-onset diabetes (diagnosed before age 60 years), or (4) prior MI.

RESULTS

Men who had both MI and diabetes were excluded. Both early and late onset of diabetes were associated with a significantly increased risk of major CHD events and all-cause mortality compared with nondiabetic men who had no CHD, even after adjustment for conventional risk factors and novel risk markers (levels of C-reactive protein and von Willebrand factor and renal dysfunction). Only men with early-onset diabetes (associated with a duration of 16.7 years) showed risk similar to those with previous MI and no diabetes. The adjusted relative risks (95% confidence intervals) for major CHD events were 1.00 (reference), 1.54 (1.07-2.21), 2.39 (1.41-4.05), and 2.51 (1.88-3.36) for groups 1 through 4, respectively.

CONCLUSION

Both early and late onset of diabetes are associated with increased risk of major CHD events and mortality, but only early onset of diabetes (associated with >10 years' duration) appears to be a CHD equivalent.