Physical activity in association with mortality among Black women diagnosed with breast cancer in the Southern Community Cohort Study.

Purpose: Physical activity (PA) is associated with many health benefits. While PA has been associated with reduced mortality after breast cancer diagnosis in many studies, few studies have examined the role of PA in breast cancer survival among underserved and minority populations, including Black women. We investigated PA in association with mortality among Black predominantly low-income breast cancer survivors in the Southern Community Cohort Study (SCCS).

Methods: Study participants were women diagnosed with incident breast cancer (n = 949) in the SCCS, which is a prospective cohort study of predominantly low-income adults aged 40-79 years recruited from 12 Southeastern states between 2002 and 2009. Participants completed a detailed baseline questionnaire, with annual follow-up for mortality via registry linkages. Cox regression models were used to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for associations of pre-diagnosis PA (measured via a validated questionnaire) with all-cause and breast cancer-specific mortality.

Results: Breast cancer survivors had a mean age of 61.1 years and most (79.3%) had a household income of < $25,000. In adjusted models, higher levels of total PA (MET-hours/day) were inversely associated with all-cause mortality with HRs (95% CIs): 0.79 (0.59-1.06), 0.66 (0.49-0.90), and 0.60 (0.43-0.84), for Q2, Q3, and Q4 (reference: Q1), respectively, p ≤ 0.01. A similar inverse association was found for breast cancer-specific mortality.

Conclusion: Higher levels of pre-diagnosis PA were associated with improved survival among low-income Black breast cancer survivors. Resources to reduce barriers to PA participation and increase support for education and intervention efforts to promote PA among Black women are needed.