Physical activity and telomere length in early stage breast cancer survivors

INTRODUCTION: Telomere length (TL) is a biomarker of accumulated cellular damage and human aging. Evidence in healthy populations suggests that TL is impacted by a host of psychosocial and lifestyle factors, including physical activity. This is the first study to evaluate the relationship between self-reported physical activity and telomere length in early stage breast cancer survivors. METHODS: A cross-sectional sample of 392 postmenopausal women with stage I-III breast cancer at an outpatient oncology clinic of a large university hospital completed questionnaires and provided a blood sample. TL was determined using terminal restriction fragment length analysis of genomic DNA isolated from peripheral blood mononuclear cells. Physical activity was dichotomized into two groups (none versus moderate to vigorous) using the International Physical Activity Questionnaire. Multivariate linear and logistic regression analyses were performed to identify factors associated with mean TL and physical activity. RESULTS: Among participants, 66 (17%) did not participate in any physical activity. In multivariate model adjusted for age, compared to those who participated in moderate to vigorous physical activity, women who participated in no physical activity had significantly shorter TL (adjusted coefficient β = −0.22; 95% confidence interval (CI), −0.41 to −0.03; P = .03). Non-white race, lower education and depressive symptoms were associated with lack of self-reported physical activity (P < 0.05 for all) but not TL. CONCLUSION: Lack of physical activity is associated with shortened TL, warranting prospective investigation of the potential role of physical activity on cellular aging in breast cancer survivors. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13058-014-0413-y) contains supplementary material, which is available to authorized users.