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.
Physical activity and telomere length in early stage breast cancer survivors
Improvements in the diagnosis and treatment of breast cancer have created a cohort of breast cancer survivors now surpassing three million women [1]. Physical activity can help improve the long-term psychological and physical health of breast cancer survivors, and potentially reduce the risk of disease recurrence and mortality [2]–[4], but questions remain regarding the influence of physical activity on measures of health at a cellular level. Telomere length (TL) is increasingly being examined as a biomarker of accumulated cellular damage and human aging [5]. Telomeres are repetitive nucleoprotein structures on the end of chromosomes with the main purposes of maintaining genomic stability and protecting against unbridled cellular division. As the cell divides with time, TL progressively shortens until critically short telomeres eventually lead to cell death or senescence. The examination of TL holds promise for identifying behavioral and environmental factors that can promote health and recovery in the context of cancer.
Previous research has demonstrated that TL can be impacted by a host of lifestyle and psychosocial factors [6]. Specifically, emerging evidence suggest that physical activity and regular exercise may positively impact TL in healthy individuals [7]. A cross-sectional study of 44 postmenopausal women compared the TL of habitual exercisers to women with a sedentary lifestyle [8]. Habitual exercisers had significantly longer TL than sedentary women and, even after adjusting for covariates, habitual exercise accounted for 75% of the variance in TL. The impact of physical activity on TL has also been examined in terms of exercise energy expenditure. In a study of 69 men and women between the ages of 50 and 70 years, individuals reporting moderate levels of physical activity had longer TL than participants at the lower and higher ends of the energy expenditure spectrum [9]. Despite the emerging evidence that physical activity may have a positive impact on TL and the growing interest in survivorship programs that encourage breast cancer survivors to be more active, no study has evaluated the association between physical activity and cellular aging in breast cancer survivors.
This study aims to evaluate the association between self-reported physical activity and TL in a large cross-sectional sample of postmenopausal breast cancer survivors. This examination is important as clinical outcomes in the context of breast cancer survivorship (for example, recurrence, cancer-specific mortality and overall mortality) are likely dependent on a complex interplay between cancer and host biology [2]. Identifying a biomarker that can be modified by behavioral approaches such as physical activities will further allow us to examine the specific mechanisms of physical activities underlying the potential positive effect on clinical outcomes. We hypothesized that those who were not participating in physical activity would have shorter telomeres than those who engaged in moderate to rigorous physical activity. As a secondary aim, we also sought to identify factors related to lack of physical activity in this population.
in early stage breast cancer
survivors