Nativity and Healthy Lifestyle Index in a Pooled Cohort of Female Breast Cancer Survivors from Northern California.

Background: In the US, breast cancer (BC) is common in Asian, Hispanic, and non-Hispanic White (NHW) women, many of whom are immigrants. A healthy lifestyle is vital to survival, but it is unknown how lifestyle varies by nativity among survivors.

Methods: The study included 4,754 racially diverse, female BC survivors from the Northern California, Exploring Networks in a Cohort of Latina and Asian Emigrants, lifestyle, and Vital status (ENCLAVE) Study. We generated a healthy lifestyle index (HLI) based on World Cancer Research Fund/American Institute for Cancer Research cancer prevention recommendations. Log-binomial regression models, controlling for socio-demographics, were used to evaluate associations between nativity and the highest tertile of HLI, as well as the optimal category of each HLI component.

Results: Foreign-born (vs. US-born) women were more likely to have a high HLI (prevalence ratio (PR)=1.44, 95% confidence interval (CI): 1.31-1.59). In stratified models, we observed stronger associations among Hispanic (PR=1.76, 95% CI: 1.39-2.24) and Asian (PR=1.60, 95% CI: 1.32-1.94) vs. NHW (PR=1.26, 95% CI: 1.08-1.47) women (p-interaction=0.02). Foreign-born (vs. US-born) women were more likely to have a waist circumference<31.5 inches (PR=1.19, 95% CI: 1.03-1.37); be normal-weight (PR=1.23, 95% CI: 1.11-1.37); never smoke (PR=1.11, 95% CI: 1.06-1.17); and consume no sweets (PR=1.44, 95% CI: 1.21-1.70), low red meat (PR=1.46, 95% CI: 1.33-1.60), and high fruits and vegetables (PR=1.46, 95% CI: 1.32-1.62).

Conclusion: Among women diagnosed with BC, foreign-born women had a healthier lifestyle than US-born women.

Impact: Lifestyle differences by nativity in BC survivors may help clarify prognostic differences by nativity.