Hispanic ethnicity as a moderator of the effects of aerobic and resistance exercise on physical fitness and quality-of-life in breast cancer survivors

Background Exercise can profoundly affect physical fitness and quality of life in breast cancer survivors; however, few studies have focused on minorities. This secondary analysis examines Hispanic ethnicity as a moderator of the effects of a 16-week aerobic and resistance exercise intervention on physical fitness and quality of life in breast cancer survivors. Methods Eligible breast cancer survivors ( n = 100) were randomized to exercise ( n = 50) or usual care ( n = 50). The exercise intervention consisted of supervised moderate-vigorous aerobic and resistance exercise thrice weekly for 16 weeks. Physical fitness and quality of life were measured at baseline, post-intervention, and 28-week follow-up (exercise only). Linear mixed-models adjusted for baseline value of the outcome, age, disease stage, adjuvant treatment, and recent physical activity were used to evaluate effect modification by ethnicity. Results The study sample included 57% Hispanic and 43% non-Hispanic breast cancer survivors. Hispanic breast cancer survivors were younger, less fit, and diagnosed with more advanced cancers compared with non-Hispanic breast cancer survivors ( p < 0.001). Ethnicity was found to moderate the effects of exercise training on all physical fitness and quality-of-life measures including VO 2max (8.4 mL/kg/min; 95% confidence interval (95% CI) 3.2 to 13.4), physical well-being (12.3; 95% CI 4.2 to 18.4), and emotional well-being (11.4; 95% CI 5.9 to 15.5). In all cases, Hispanics experienced larger benefits than non-Hispanics. Conclusions Hispanic breast cancer survivors have poorer cardiorespiratory fitness, muscle strength, and quality-of-life and therefore may derive larger benefits from exercise than non-Hispanic breast cancer survivors. Clinical exercise interventions may attenuate existing health disparities among minority breast cancer survivors. Implication of Cancer Survivors Here we report psychosocial and fitness-related disparities among Hispanic breast cancer survivors when compared with their non-Hispanic counterparts. Our exercise intervention highlights the importance of exercise for minority cancer survivors and the need for distinct, culturally tailored exercise intervention approaches to reduce psychosocial and fitness-related disparities among this understudied population of cancer survivors.