Context: There are few data directly comparing the effects of physical activity and body weight on cardiovascular biomarkers.
Objective: To examine the association of physical activity and body mass index (BMI, defined as weight in kilograms divided by the square of height in meters) alone and in combination with cardiovascular biomarkers.
Design, setting, and participants: Cross-sectional analysis of 27,158 apparently healthy US women (mean age, 54.7 years) at the time of enrollment (1992-1995) in the Women's Health Study, a randomized, double-blind, placebo-controlled trial of low-dose aspirin and vitamin E in the primary prevention of cardiovascular disease and cancer.
Main outcome measures: The association of physical activity and BMI with high-sensitivity C-reactive protein (CRP), fibrinogen, soluble intracellular adhesion molecule 1 (ICAM-1), homocysteine, low- and high-density lipoprotein (LDL and HDL) cholesterol, total cholesterol, apolipoprotein A-1 and B100, lipoprotein(a), and creatinine.
Results: Lower levels of physical activity and higher levels of BMI were independently associated (P for trend <.001) with adverse levels of nearly all lipid and inflammatory biomarkers. High BMI showed stronger associations with these biomarkers than physical inactivity. For example, using the reference group of physically active, normal weight women (energy expenditure > or =1000 kcal/week; BMI, 18.5-24.9) and adjusting for age, race, smoking, blood pressure, diabetes, menopausal status, and hormone use, the odds ratios (95% confidence intervals [CIs]) for having CRP >3 mg/L were: for inactive, normal weight women 1.26 (1.15-1.37); active, overweight 2.68 (2.41-2.98); inactive, overweight 3.11 (2.84-3.41); active, obese 8.25 (7.15-9.51); and inactive, obese 9.86 (8.84-10.99). In similar analyses, the odds ratios (95% CIs) for having HDL cholesterol <50 mg/dL were 1.20 (1.11-1.30); 2.25 (2.04-2.49); 2.62 (2.41-2.85); 4.21 (3.68-4.81); and 5.27 (4.77-5.84), respectively, and for having apolipoprotein B100 >120 mg/dL they were 1.21 (1.11-1.33); 1.86 (1.66-2.08); 2.06 (1.88-2.67); 2.35 (2.04-2.70); and 2.33 (2.09-2.59). Fibrinogen, ICAM-1, apolipoprotein A1, total cholesterol, and LDL cholesterol showed similar associations. By contrast, homocysteine, lipoprotein (a), and creatinine showed weak or nonsignificant associations.
Conclusions: High BMI was more strongly related to adverse cardiovascular biomarker levels than physical inactivity. However, within BMI categories, physical activity was generally associated with more favorable cardiovascular biomarker levels than inactivity.