Pre- to post-diagnosis weight change and associations with physical functional limitations in breast cancer survivors.

PURPOSE: We investigated pre- to post-diagnosis weight change and functional limitations in a cohort of breast cancer survivors.
METHODS: A cohort of 1,841 early-stage breast cancer survivors provided information on pre- and post-diagnosis weight and physical function on average 2 years post-diagnosis. The mean number of limitations for each BMI category and each weight change category were compared using the Wilcoxon test. Cross-sectional associations between weight change, from 1 year prior to diagnosis to 2 years post-diagnosis, and functional limitations were determined using logistic regression.
RESULTS: Women with BMI ≥ 30 kg/m(2) had significantly higher physical limitations compared to women with BMI < 25 kg/m(2) (2.06 vs 0.96 for moderate/severe limitations, 3.92 vs 3.27 for mild limitations, 1.31 vs 0.47 for lower body limitations, and 0.76 vs 0.49 for all other limitations; P < 0.0001). Women who reported a large weight gain (≥10% of pre-diagnosis weight) were more likely to report any limitation (OR = 1.79; 95% confidence interval (CI) = 1.23-2.61), a moderate/severe limitation (OR = 2.30; 95% CI = 1.75-3.02), and a lower body limitation (OR = 2.05; 95% CI = 1.53-2.76) compared to women who maintained weight within 5% of pre-diagnosis weight. However, associations between weight loss and functional limitations depended on pre-diagnosis BMI and comorbidity status. Among women without comorbidity, large weight loss (≥10% of pre-diagnosis weight) in normal-weight women was associated with higher risk of functional limitations, whereas among overweight/obese women, large weight loss appeared to be associated with a lower risk of limitations. Among women with comorbidity, moderate weight loss in overweight/obese women was associated with a higher risk of a moderate/severe physical limitation.
CONCLUSIONS: Large weight gain was associated with a higher risk of physical functional limitations, but associations between weight loss and functional limitations may depend on initial BMI and comorbidity status. IMPLICATIONS FOR CANCER SURVIVORS: In this study we found that both weight loss and weight gain among breast cancer survivors were associated with a higher risk of physical functional limitations. Weight maintenance, therefore, may be an important factor in preventing and/or reducing the risk of functional decline in breast cancer survivors.