Lifestyle Patterns and Survival Following Breast Cancer in the Carolina Breast Cancer Study

Background: Few studies have examined the impact of lifestyle patterns on survival following breast cancer. We aimed to identify distinct lifestyle patterns based on five behavior/dietary exposures among a population -based sample of women diagnosed with breast cancer and to examine their association with subsequent survival. Methods: In the Carolina Breast Cancer Study Phases I/II, we interviewed 1,808 women 20-74 years of age following diagnosis of invasive breast cancer. We determined vital status using the National Death Index (717 deaths, 427 from breast cancer; median follow-up 13.56 years). We assessed lifestyle patterns using a latent class analysis based on five behavioral and dietary exposures: current versus never former smokers; low versus high vegetable and fruit intake; high and low/moderate, versus no alcohol consumption; and no and low/moderate, versus high regular physical activity. We used Cox regression to estimate covariate-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause mortality, and cause -specific and subdistrihution EIRs for breast cancer -specific mortality within 5 years and 13 years postdiagnosis conditional on 5 -year survival. Results: We identified three distinct lifestyle patterns: healthy behavior and diet (n = 916); healthy behavior and unhealthy diet (n = 624); and unhealthy behavior and diet (n = 268). The unhealthy (vs. healthy) behavior and diet pattern was associated with a 13 -year conditional all -cause mortality HR of 1.4 (95% CI = 1.1, 1.9) and with 13 -year conditional breast cancer -specific and suhdistribution HRs of 1.2 (95% CI = 0.79, 1.9) and 1.2 (95% CI= 0.77, 1.8), respectively. Conclusions: Behavioral and dietary patterns can be used to identify lifestyle patterns that influence survival patterns following breast cancer diagnosis.