Effect of exercise and/or reduced calorie dietary interventions on breast cancer-related endogenous sex hormones in healthy postmenopausal women

Abstract

BackgroundPhysical inactivity and being overweight are modifiable lifestyle risk factors that consistently have been associated with a higher risk of postmenopausal breast cancer in observational studies. One biologic hypothesis underlying this relationship may be via endogenous sex hormone levels. It is unclear if changes in dietary intake, physical activity, or both, are most effective in changing these hormone levels.ObjectiveThis systematic review and meta-analysis examines the effect of reduced caloric dietary intake and/or increased exercise levels on breast cancer-related endogenous sex hormones.MethodsWe conducted a systematic literature search in MEDLINE, Embase, and Cochrane’s Central Register of Controlled Trials (CENTRAL) up to March 2017. Main outcome measures were breast cancer-related endogenous sex hormones.Randomized controlled trials (RCTs) reporting effects of reduced caloric intake and/or exercise interventions on endogenous sex hormones in healthy, physically inactive postmenopausal women were included. Studies including women using hormone therapy were excluded. The methodological quality of each study was assessed by the Cochrane’s risk of bias tool.ResultsFrom the 2599 articles retrieved, seven articles from six RCTs were included in this meta-analysis. These trials investigated 1588 healthy postmenopausal women with a mean age ranging from 58 to 61 years. A combined intervention of reduced caloric intake and exercise, with durations ranging from 16 to 52 weeks, compared with a control group (without an intervention to achieve weight loss) resulted in the largest beneficial effects on estrone treatment effect ratio (TER) = 0.90 (95% confidence interval (CI) = 0.83–0.97), total estradiol TER = 0.82 (0.75–0.90), free estradiol TER = 0.73 (0.66–0.81), free testosterone TER = 0.86 (0.79–0.93), and sex hormone biding globulin (SHBG) TER = 1.23 (1.15–1.31). A reduced caloric intake without an exercise intervention resulted in significant effects compared with control on total estradiol TER = 0.86 (0.77–0.95), free estradiol TER = 0.77 (0.69–0.84), free testosterone TER = 0.91 (0.84–0.98), and SHBG TER = 1.20 (1.06–1.36). Exercise without dietary change, versus control, resulted in borderline significant effects on androstenedione TER = 0.97 (0.94–1.00), total estradiol TER = 0. 97 (0.94–1.00), and free testosterone TER = 0. 0.97 (0.95–1.00).Conclusions and relevanceThis meta-analysis of six RCTs demonstrated that there are beneficial effects of exercise, reduced caloric dietary intake or, preferably, a combination of exercise and diet on breast cancer-related endogenous sex hormones in physically inactive postmenopausal women.Electronic supplementary materialThe online version of this article (10.1186/s13058-018-1009-8) contains supplementary material, which is available to authorized users.

Effect of Physical Training on the Levels of Sex Hormones and the Expression of Their Receptors in Rats With Induced Mammary Cancer in Secondary Prevention Model – Preliminary Study

“…A reduction in receptor expression results in the lack of cell stimulation by sex hormones, followed by cell apoptosis (17). We found statistically insignificant differences between the estradiol levels in PT vs. SC groups, in accordance with other authors (9,15,28).…”

“…Many scientific reports indicate a protective effect of physical activity on breast cancer (8,9,13,(15)(16)(17), including in patients after comprehensive breast cancer treatment (8,9,(18)(19)(20)(21)(22)(23)(24). From the results of our study, we found two mechanisms which confirm these observations, namely desensitization of cells due to reduced expression of ER and PR, as well as increased apoptosis which positively correlated with the level of training intensity.…”

Physical Activity in Cancer Prevention and Survival: A Systematic Review

“…Furthermore, randomized clinical trials testing the effects of physical activity on biomarkers of cancer, as well as animal models, have provided important mechanistic information to support the relationship between physical activity and reduced cancer risk. (66)(67)(68)(69) For cancer survival, the PAGAC identified several research needs. Because of the increasing length of cancer survivorship, there is need to continue long-term follow-up of cohorts of cancer survivors, with repeated self-report and device-based measures of physical activity, to determine long-term associations of physical activity with recurrence and survival.…”

Long-term weight loss maintenance, sex steroid hormones, and sex hormone-binding globulin

“…18 This and other diabetes prevention studies found sustained and long-term benefits including a reduction in the cumulative incidence of diabetes, and lower fasting glucose levels, even after intervention activities ceased. [18][19][20] Beneficial changes in circulating sex steroid hormones with weight loss have been observed in shorter-term randomized clinical trials of exercise or dietary weight loss, and are principally attributed to reductions in adiposity, [21][22][23][24][25][26] including the 12-month results in our study. 7 An ancillary study nested within the Diabetes Prevention Program (DPP) reported that reductions in visceral and subcutaneous adipose tissue in overweight glucose intolerant participants, were independently associated with significant increases in in SHBG and estrone in postmenopausal women.…”