Background: We sought to estimate the risk for coronary heart disease (CHD) associated with leisure time physical activity (LTPA) and work-related physical strain (WRPS) after careful adjustment for other established risk factors and to elucidate the association of physical activity with various hemostatic and inflammatory markers.
Methods: Case-control study including 312 patients aged 40 to 68 years with stable CHD (angiographically confirmed) and 479 age- and sex-matched controls. Main outcome measures were odds ratio for CHD associated with LTPA and WRPS and associations of physical activity with inflammatory and other biochemical markers after adjustment for covariates.
Results: LTPA showed a clear inverse association with risk of CHD. Compared with subjects who reported no summer LTPA, the odds ratio for CHD was 0.85 (95% confidence interval [CI], 0.47-1.53) in the category <1 h/wk; 0.60 (95% CI, 0.38-0.95) in the category 1-2 h/wk; and 0.39 (95% CI, 0.26-0.59) in the category >2 h/wk, after full adjustment for covariates. Similar results were obtained for winter LTPA. By contrast, there was a strong positive association between WRPS and risk of CHD. Furthermore, levels of C-reactive protein, serum amyloid A, interleukin 6, and intercellular adhesion molecule 1 were inversely and independently associated with LTPA, but not with WRPS.
Conclusions: This study provides further evidence that LTPA, but not WRPS, is associated with a decreased risk of CHD, effective at even moderate levels. It further demonstrates that LTPA is associated with beneficial effects on the inflammatory response. This may represent one mechanism to explain the benefits of LTPA on coronary risk.