Context: Despite reductions in cardiovascular disease (CVD) mortality over the past few decades, it is unclear whether adults with and without diabetes have experienced similar declines in CVD risk.
Objective: To determine whether adults with and without diabetes experienced similar declines in incident CVD in 1950-1995.
Design, setting, and participants: Participants aged 45-64 years from the Framingham Heart Study original and offspring cohorts who attended examinations in 1950-1966 ("earlier" time period; 4118 participants, 113 with diabetes) and 1977-1995 ("later" time period; 4063 participants, 317 with diabetes). Incidence rates of CVD among those with and without diabetes were compared between the earlier and later periods.
Main outcome measures: Myocardial infarction, coronary heart disease death, and stroke.
Results: Among participants with diabetes, the age- and sex-adjusted CVD incidence rate was 286.4 per 10,000 person-years in the earlier period and 146.9 per 10,000 in the later period, a 49.3% (95% confidence interval [CI], 16.7%-69.4%) decline. Among participants without diabetes, the age- and sex-adjusted incidence rate was 84.6 per 10,000 person-years in the earlier period and 54.3 per 10,000 person-years in the later period, a 35.4% (95% CI, 25.3%-45.4%) decline. Hazard ratios for diabetes as a predictor of incident CVD were not different in the earlier vs later periods.
Conclusions: We report a 50% reduction in the rate of incident CVD events among adults with diabetes, although the absolute risk of CVD is 2-fold greater than among persons without diabetes. Adults with and without diabetes have benefited similarly during the decline in CVD rates over the last several decades. More aggressive treatment of CVD risk factors and further research on diabetes-specific factors contributing to CVD risk are needed to further reduce the high absolute risk of CVD still experienced by persons with diabetes.