Keeping Active, Not Smoking Can Reduce but Not Abolish CV Risks of Obesity

News Author: Shelley Wood
CME Author: Désirée Lie, MD, MSEd

From Heartwire — a professional news service of WebMD

June 16, 2008 — What people do, whether they smoke, and what they eat can mitigate the adverse cardiovascular effects of obesity, but they cannot do away with them altogether, researchers say. While other studies have investigated the relationship between fitness and fatness, this latest study also factors in dietary habits and smoking.

"Our study confirms the findings observed in some epidemiological studies, that although physical activity is important, it does not abolish the excess cardiovascular risk observed among the obese," first author on the study, Dr Majken K Jensen (Aarhus University Hospital, Aalborg, Denmark), told heartwire. The results, Jensen continued, "suggest that both obesity and physical activity affect the risk of acute coronary syndrome (ACS) and that the lowest risk is observed among the leanest individuals who are the most physically active. The new information is really not on physical activity, but that we extended the investigation to include the role of obesity in combination with other lifestyle risk factors."

Jensen et al report the results of their study published online June 9, 2008 in Circulation.

Does weight matter?

Jensen and colleagues reviewed a median of 7.7 years of follow-up data for the almost 55,000 participants in the Danish Diet, Cancer, and Health study. All participants were middle-aged (50-64 years) and free of coronary artery disease (CAD) and cancer at baseline.

"Some people might think that it doesn't matter if they are overweight as long as they are active," Jensen explained. "Or, similarly, think that it doesn't matter that they are overweight because they otherwise adhere to a healthy lifestyle, with regard to not smoking, eating healthy, and being physically active. We wanted to explore this further."

They found that developing acute coronary syndromes over this period was significantly associated with increased body-mass index (BMI): for every unit of BMI increase, risk of ACS was increased by 5% in women and by 7% in men.

Nonsmokers who were obese had a reduced risk of ACS as compared with people who were obese and heavy smokers (≥ 15 g/day). Similarly, obese but physically active people (≥ 3.5 hours per week) fared slightly better than inactive obese subjects (less than one hour per week). By contrast, adherence to a Mediterranean-style diet, suggested by high scores on the Mediterranean diet scale, appeared to have no impact on risk of future events in obese subjects.

Pearls for Practice

• Increasing BMI vs healthy BMI is associated with a strong and graded increase in the risk for ACS in men and women.
• The increased risk for ACS in obese participants is further increased by the presence of hypertension, diabetes, hypercholesterolemia, smoking, and a sedentary lifestyle but not by lack of adherence to the Mediterranean diet.