Long-term physical activity trends in breast cancer survivors

Abstract

Background: Physical activity is associated with reduced mortality and higher quality of life in breast cancer survivors; however, limited data on the prevalence of activity and long-term trends after diagnosis are available.

Methods: A multiethnic cohort of 631 women (18-64 years) with stage 0 to IIIA breast cancer was followed for 10 years. Recreational aerobic activity (MET-h/wk) was ascertained for the year before diagnosis (baseline), 24 months, 5 years, and 10 years after enrollment. Women were classified according to U.S. physical activity guidelines (≥150 min/wk moderate or ≥75 min/wk vigorous activity). The OR for meeting guidelines at 5 and 10 years according to baseline factors was estimated using logistic regression. The change in MET-h/wk was predicted using linear regression.

Results: Prediagnosis, 34% of women met physical activity guidelines; 34.0%, 39.5%, and 21.4% met guidelines at 24 months, 5 years, and 10 years after enrollment, respectively. Less than 8% of survivors met guidelines at all follow-up periods. Over 10 years, recreational aerobic activity decreased by a mean ± SD of 4.3 ± 16.2 MET-h/wk. Meeting guidelines pre-diagnosis was strongly associated with meeting guidelines at 5 years [OR (95% confidence interval; CI): 2.76 (1.85-4.1)] and 10 years [OR (95% CI): 3.35 (2.13-5.28)]. No other demographic or prognostic factors were significantly associated with the 10-year change in MET-h/wk.

Conclusion: The vast majority of early breast cancer survivors do not meet national exercise recommendations 10 years postdiagnosis.

Impact: Physical activity levels are low in breast cancer survivors across the 10 years postdiagnosis; nonetheless, the predictors of activity in this population remain poorly understood.

Figures

Figure 1

Average MET-hrs/week of moderate-to-vigorous aerobic exercise among breast cancer survivors over 10 years of follow-up according accordint to i) age, ii) BMI, iii) race/ethnicity & study site, and iv) initial breast cancer treatment.

Figure 2

Percentage of breast cancer survivors meeting aerobic physical activity recommendations over 10 years of follow-up.