Comparison of lifestyle-based and traditional cardiovascular disease prediction in a multiethnic cohort of nonsmoking women.
BACKGROUND
Healthy levels of lifestyle factors can reduce the risk of cardiovascular disease. However, except for smoking status, often considered a traditional risk factor, their effect on cardiovascular risk prediction is unclear.


METHODS AND RESULTS
We used a case-cohort design of postmenopausal nonsmokers in the multiethnic Women's Health Initiative Observational Study (1587 cases and 1808 subcohort participants) with a median follow-up of 10 years in noncases. Compared with nonsmokers with no other healthy lifestyle factors (healthy diet, recreational physical activity, moderate alcohol use, and low adiposity), the risk of cardiovascular disease was lower for each additional factor (hazard ratio for trend, 0.82; 95% confidence interval, 0.76-0.89), with a 45% reduction in risk with all factors (95% confidence interval, 0.36-0.84). When lifestyle factors were added to traditional risk factor models (variables from the Pooled Cohort and Reynolds risk scores), only recreational physical activity remained independently associated with the risk of cardiovascular disease. The addition of detailed lifestyle measures to traditional models showed a change in the integrated discrimination improvement and continuous net reclassification improvement (P<0.01 for both) but had little impact on more clinically relevant risk stratification measures.


CONCLUSIONS
Although lifestyle factors have important effects on cardiovascular disease risk factors and subsequent risk, their addition to established cardiovascular disease risk models does not result in clear improvement in overall prediction.