The effects of moderate physical activity on menstrual cycle patterns in adolescence: Implications for breast cancer prevention

Bernstein, Leslie; Ross, Ronald K.; Løbo, Rogerio A.; Hanisch, Rosemarie; Krailo, Mark; Henderson, Brian E.

doi:10.1038/bjc.1987.139

Cited by 219 publications

(104 citation statements)

References 30 publications

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“…Associations between breast cancer risk associated with birth weight and height lend support for the hypothesis that early events also may influence subsequent risk (21). It has been proposed that exposure to strenuous physical activity in adolescence may cause amenorrhea and result in reduced risk of breast cancer (22). As in this study, others have sought to estimate associations with physical activity at various times in a woman's life as well as with a lifetime composite activity index.…”

Section: Discussionmentioning

confidence: 85%

Physical Activity and Breast Cancer Risk Among Women in the Southwestern United States

Slattery

Edwards

Murtaugh

et al. 2007

Annals of Epidemiology

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Physical activity may influence breast cancer risk through multiple mechanisms and at different periods in life. In this study we evaluate breast cancer risk associated with total and vigorous physical activity at ages 15, 30, and 50 years and the referent year prior to diagnosis/selection. Participants were non-Hispanic white (NHW) (1527 cases and 1601 control subjects) and Hispanic/American Indian (HAI) (798 cases and 924 controls) women. Both total and vigorous activity reduced risk of breast cancer in a dose-response manner. Among premenopausal women, only high total metabolic equivalent of the task (MET) hours of activity during the referent year was associated with reduced breast cancer risk in NHW women (odds ratio [OR] 0.62; 95% confidence interval [CI] 0.43, 0.91). Among postmenopausal women, physical activity had the greatest influence among women not recently exposed to hormones. Among these women, high total lifetime activity reduced risk of breast cancer for both NHW (OR 0.60; 95% CI 0.36, 1.02; p trend 0.01) and HAI women (OR 0.52; 95% CI 0.23, 1.16; p trend 0.07). Additionally, high total MET hours of activity at age 30 years (OR 0.56; 95% CI 0.37, 0.85) and at age 15 years (OR 0.57; 95% CI 0.38, 0.88) reduced breast cancer risk among postmenopausal NHW women not recently exposed to hormones. Among HAI women, more recent activity performed during the referent year and at age 50 appeared to have the greatest influence on breast cancer risk. Among postmenopausal NHW women. there was a significant interaction between physical activity and hormone replacement therapy (p value, 0.01), while among postmenopausal HAI women, physical activity interacted with body mass index (p value, 0.04). These data suggest that physical activity is important in reducing risk of breast cancer in both NHW and HAI women.

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Section: Discussionmentioning

confidence: 85%

Physical Activity and Breast Cancer Risk Among Women in the Southwestern United States

Slattery

Edwards

Murtaugh

et al. 2007

Annals of Epidemiology

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“…27,28 These alterations in menstrual function have been associated with reduced levels of estradiol, progesterone, and follicle-stimulating hormone, particularly during adolescence. 27,29,30 Studies of recreational athletes suggest that ovarian function may be altered in women who engage in less strenuous activity through lower mean hormone levels, longer menstrual cycle lengths, 31,32 or the occurrence of anovulatory menstrual cycles, 33 but to our knowledge the data are not as conclusive as those for athletes. Recent physical activity may also act through hormonal mechanisms by continuing to impact ovarian hormone levels among premenopausal women, may directly lower estrogen levels, 34 or may alter circulating estrogen levels of postmenopausal women indirectly 9 by lowering BMI or maintaining weight among postmenopausal women.…”

Section: Discussionmentioning

confidence: 90%

Lifetime recreational exercise activity and risk of breast carcinoma in situ

Patel

Press

Meeske

et al. 2003

Cancer

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The aim of this study is the creation of an empirical model that can be used to predict the viscosity of a semicrystalline polymer melt for polymer process control. We have developed an empirical viscosity equation from both analysis and experimentation that takes into consideration the effect of temperature on both the flow behavior and the consistency index in the power law. The analysis is based on previously published literature, whereas the experimental data have been obtained from both the literature and laboratory investigations. The coefficients of the empirical model for low‐density polyethylene and polypropylene have been obtained from the experimental data derived from capillary rheometer measurements in the laboratory. This empirical model is able to produce results matching the experimental data with remarkable accuracy. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 3045–3057, 2003

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“…To date, immune function has not been related to risk of breast cancer and hence this potential mechanism is not discussed further. Very high levels of activity may reduce the frequency of ovulation or the length of the luteal phase (Bernstein et al, 1987), thus reducing exposure to oestradiol and progesterone. Some evidence suggests that physical activity insufficient to cause anovulation may also reduce oestrogen levels (Bullen et al, 1985).…”

Section: Discussionmentioning

confidence: 99%

Physical activity and risk of breast cancer in premenopausal women

et al. 2003

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Physical activity appears to be inversely related to risk of breast cancer, yet the results remain inconsistent. To evaluate this relation among premenopausal women and examine variation in risk according to level of obesity and use of oral contraceptives (OCs), the authors examined data from the Nurses' Health Study II. During 10 years of follow-up, 849 cases of invasive premenopausal breast cancer were confirmed. Physical activity was assessed by self-report at baseline and during follow-up using a validated questionnaire. Total physical activity was unrelated to risk of breast cancer. Women engaging in X27 metabolic equivalent (MET)-h week À1 had a multivariate-adjusted relative risk (RR) of 1.04 (95% confidence interval (CI) 0.82 -1.33) compared to those in the o3 METh week À1 category. Among women with a BMI X30 kg m À2 , we observed a significant positive dose -response relation (P ¼ 0.04). Activity was unrelated to breast cancer risk at lower levels of BMI. A test for interaction between activity and BMI (o30, X30 kg m À2 ) was statistically significant (P ¼ 0.02). Among current OC users, higher activity was associated with a non-significantly lower risk of breast cancer (RR ¼ 0.59, 95% CI 0.30 -1.16 for X27 vs o9 MET-h week À1 , P for linear trend ¼ 0.14). These results show no overall association between physical activity and risk of breast cancer among premenopausal women, but suggest that the effect of physical activity could be substantially modified by the underlying degree of adiposity. The potential interactions between physical activity, adiposity, and current use of OCs require further study. The relation of physical activity to risk of breast cancer has been assessed by the International Agency for Research on Cancer, which concluded that, although studies have not been entirely consistent, the overall results support a reduction in risk with higher levels of activity (International Agency for Research on Cancer, 2002). The majority of studies, however, have been focused on postmenopausal breast cancer. Also, upon review of more than 30 studies, it was noted that the most important time periods in life for activity is not currently known. Furthermore, which activities may offer the greatest protection have not been systematically examined.In a previous analysis of the Nurses' Health Study II (NHSII) cohort with 372 cases among predominantly premenopausal women, Rockhill et al (1998) observed no association between nonoccupational activity levels in late adolescence or the recent past and risk of breast cancer. We now extend that analysis, adding 477 additional premenopausal cases in an effort to understand better the relation between physical activity and risk of premenopausal breast cancer.In addition to evaluating the type of physical activity, we examined the relation between activity and breast cancer within subgroups of adiposity and oral contraceptive (OC) use, which we hypothesised, might modify the relationship. Potential health effects of (OCs) were the original focus of the NHS II coh...

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The effects of moderate physical activity on menstrual cycle patterns in adolescence: Implications for breast cancer prevention

Cited by 219 publications

References 30 publications

Physical Activity and Breast Cancer Risk Among Women in the Southwestern United States

Physical Activity and Breast Cancer Risk Among Women in the Southwestern United States

Lifetime recreational exercise activity and risk of breast carcinoma in situ

Physical activity and risk of breast cancer in premenopausal women

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