Myocardial Infarction and Ischemic Heart Disease in Overweight and Obesity

Study Questions:

What is the association between overweight and obesity with and without the metabolic syndrome with risk of myocardial infarction (MI) and ischemic heart disease (IHD)?

Methods:

This was a population-based retrospective cohort study of patients from the Copenhagen General Population Study. Patients were categorized according to body mass index (BMI) as normal weight, overweight, or obese, and according to absence or presence of the metabolic syndrome. Hazard ratios for incident MI and IHD were calculated for combinations of BMI category and absence or presence of the metabolic syndrome.

Results:

Median follow-up was 3.6 (2.4-5.7) years, during which time 634 individuals had incident MI and 1,781 individuals were diagnosed with IHD. For MI, multivariable adjusted hazard ratios versus normal weight individuals without the metabolic syndrome were 1.26 (95% confidence interval [CI], 1.00-1.161) in overweight and 1.88 (95% CI, 1.34-2.63) in obese individuals without the metabolic syndrome, and 1.39 (95% CI, 0.96-2.02) in normal weight, 1.70 (95% CI, 1.35-2.15) in overweight, and 2.33 (95% CI, 1.81-3.00) in obese individuals with the metabolic syndrome. Results were similar, but of lower magnitude, for IHD. Addition of the metabolic syndrome to a multivariable prediction model including BMI and other clinical characteristics (including physical inactivity) improved the C-statistic only slightly for risk of MI (0.71-0.72; comparison p = 0.03), but not for IHD (0.60 for both models).

Conclusions:

Overweight and obesity are risk factors for MI and IHD, independent of the presence or absence of the metabolic syndrome, which is minimally more valuable than BMI in identifying at-risk individuals.

Perspective:

While some studies have suggested that overweight and obesity are not associated with cardiovascular disease in those without the metabolic syndrome, the present analysis adds to other evidence that these conditions are associated with excess risk and are not benign entities. As the authors postulate, their findings may well be explained by overweight and obese individuals free of metabolic syndrome at baseline developing the other components of the syndrome over time. Providers should continue to encourage risk factor modification and weight loss in those who are overweight and obese, even in the absence of the metabolic syndrome.

Clinical Topics: Diabetes and Cardiometabolic Disease

Keywords: Metabolic Syndrome X, Myocardial Infarction, Body Mass Index, Overweight, Weight Loss, Risk Factors, Obesity


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