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.
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