Cancer prevention IThe Role of Physical Activity in Breast Cancer Etiology
Section snippets
Methods
Epidemiologic studies were eligible for inclusion in this review if they included a measure of some type of physical activity and reported its association with breast cancer incidence. A review of all published literature to March 2010 was undertaken and 91 epidemiologic studies were identified.2 When duplicate publications from the same study were removed, 73 individual studies remained that included 33 prospective cohort studies and 40 case-control studies. The study design, sample size,
Overall Associations Between Physical Activity and Breast Cancer Risk
Breast cancer risk was found to be decreased among women who were the most physically active compared to the least active in 29 of the 73 studies (40%) included in this review and this risk reduction was statistically significant.2 In addition, eight other studies (11%) observed risk reductions for breast cancer that were of borderline statistical significance and 14 (19%) studies had risk reductions that did not achieve statistical significance. No association between physical activity and
Discussion
There is now consistent and strong evidence for an effect of physical activity on breast cancer risk reduction found in these observational epidemiologic studies. Given the limitations of these studies outlined above, arguments have been made that, for an improved understanding of the effect of exercise on breast cancer risk, randomized controlled exercise intervention trials are needed that examine the effect of different types, doses and timing of activity on risk and biomarkers involved in
Conclusion
The 73 observational epidemiologic studies included in this review have provided strong and consistent evidence that physical activity reduces breast cancer risk by about 25%. Furthermore, there is clear evidence that a dose-response effect exists with increasing levels of physical activity and decreasing risks of breast cancer. The effect of physical activity is particularly strong for household and recreational activity, for activity done later in life or sustained over a lifetime and that is
Acknowledgment
Dr Christine Friedenreich is supported by Health Senior Scholar Award from the Alberta Heritage Foundation for Medical Research. The author acknowledges Heather Neilson for critical review of the manuscript.
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2020, Clinical NutritionCitation Excerpt :The evidence-based concepts to prevent breast cancer in this high-risk population are limited. Apart from mastectomy, lifestyle interventions comprising exercise [4] and the Mediterranean diet (MedD) have been proposed [5,6]. The MedD describes the traditional dietary pattern in southern Italy, Crete and Greece [7].
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2019, Presse MedicaleThe short-term stress response – Mother nature's mechanism for enhancing protection and performance under conditions of threat, challenge, and opportunity
2018, Frontiers in NeuroendocrinologyCitation Excerpt :In keeping with this idea, recently conducted mouse studies have shown that exposure to short-term stress (three times per week) in a manner that mimics exercise-induced activation of short-term stress physiology, significantly enhanced anti-tumor immunity and decreased tumor burden (Dhabhar et al., 2010). These findings suggest that regular activation of the short-term stress response, in a frequency that does not induce chronic stress, may be one mechanism mediating findings from human studies showing that moderate and regular physical activity reduces the risk of cancer occurrence (Friedenreich, 2010; Friedenreich et al., 2010), progression, and mortality (Clague and Bernstein, 2012). ( 2) Intense prolonged exercise (Gleeson, 2007) or exercising under extreme environmental conditions (Walsh and Whitham, 2006), may lead to chronic exposure to stress hormones that make the individual susceptible to the deleterious health effects of chronic stress.