Abstract
Recent epidemiologic evidence suggests that prediagnosis physical activity is associated with survival in women diagnosed with breast cancer. However, few data exist for racial/ethnic groups other than non-Latina whites. To examine the association between prediagnosis recreational physical activity and mortality by race/ethnicity, we pooled data from the California Breast Cancer Survivorship Consortium for 3 population-based case-control studies of breast cancer patients (n=4,608) diagnosed from 1994 to 2002 and followed up through 2010. Cox proportional hazards models provided estimates of the relative hazard ratio for mortality from all causes, breast cancer, and causes other than breast cancer associated with recent recreational physical activity (i.e., in the 10 years before diagnosis). Among 1,347 ascertained deaths, 826 (61%) were from breast cancer. Compared with women with the lowest level of recent recreational physical activity, those with the highest level had a marginally decreased risk of all-cause mortality (hazard ratio=0.88, 95% confidence interval: 0.76, 1.01) and a statistically significant decreased risk of mortality from causes other than breast cancer (hazard ratio=0.63, 95% confidence interval: 0.49, 0.80), and particularly from cardiovascular disease. No association was observed for breast cancer-specific mortality. These risk patterns did not differ by race/ethnicity (non-Latina white, African American, Latina, and Asian American). Our findings suggest that physical activity is beneficial for overall survival regardless of race/ethnicity.