Association of Physical Activity with Reproductive Hormones: The Penn Ovarian Aging Study

Aerobic Exercise with Mediterranean-DASH Intervention for Neurodegenerative Delay Diet Promotes Brain Cells’ Longevity despite Sex Hormone Deficiency in Postmenopausal Women: A Randomized Controlled Trial

Objective

To investigate the combined impact of aerobic exercise and Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet on brain cells longevity in spite of sex hormones deficiency in obese postmenopausal women.

Design

A parallel randomized clinical trial. Subjects/Patients. Sixty-eight eligible postmenopausal women were randomly assigned to one of two groups, one experimental and one control. The participants' age ranged from 60 to 75 years, and their body mass index ranged from 30 to 39.9 kg/m².

Methods

An experimental group whose members followed moderate-intensity treadmill exercise three times/week for three months with MIND diet and a control group whose members followed the MIND diet only. In addition to serum sex hormones, pre- and post-12-week assessments were performed to measure serum sex hormones as well as cognitive and functional levels.

Results

The experimental group showed after intervention highly significant changes (p < 0.01) in sex hormones, cognitive functions, and functional levels compared with the control group (p < 0.05). In addition, no correlation was found between the measured variables in both groups after intervention (p > 0.05).

Conclusion

Aerobic exercise combined with the MIND diet improves cognitive and functional levels and substitutes sex hormones deficiency in postmenopausal women, which affects the longevity of brain health.

Aerobic exercise with diet induces hormonal, metabolic, and psychological changes in postmenopausal obese women

Physical activity and diet are recommended lifestyle strategies to improve human health. Consequently, this study aimed to investigate the impact of aerobic exercise combined with dietary restriction on hormonal, metabolic, and psychological variables in postmenopausal women. Eligible 60 women were enrolled and assigned into two equal groups; the experimental group performed aerobic exercise three times per week for 12 weeks with diet restriction, and the control group only received the same diet program. Serum levels of sex hormones, insulin resistance, and depression scores were measured before and after the intervention.

Results

All measured variables were significantly changed in the experimental group compared to the control group (P = 0.001).

Conclusion

Changes in sex hormones are a biological marker of metabolic complications such as insulin resistance, which can be reduced with exercise and diet. In addition, they are effective therapeutic interventions in the treatment of mild depression.

Trial registration

Registration identifier number of this study is: NCT05136742 on https://register.ClinicalTrials.gov.

Accelerometer-measured Physical Activity, Reproductive Hormones, and DNA Methylation

INTRODUCTION/PURPOSE

Limited studies have examined the association of physical activity with reproductive hormones, DNA methylation, and pubertal status among adolescents.

METHODS

Among 248 boys and 271 girls, we estimated daily physical activity levels based on 7 d of wrist-worn accelerometer data. We used an isotemporal substitution paradigm and sex-stratified regression models to examine the association of physical activity levels with 1) testosterone, cortisol, progesterone, and androstenedione concentrations; 2) DNA methylation of long interspersed nucleotide (LINE-1) repeats and the genes H19, hydroxysteroid (11-Beta) dehydrogenase 2 (HSD11B2), and peroxisome proliferator-activated receptor alpha (PPARA) from blood leukocytes; and 3) Tanner stages, adjusted for age, BMI, and socioeconomic status.

RESULTS

In boys, substituting 30 min of moderate physical activity for 30 min of sedentary behavior per day was associated with 29% (-49%, 0%) of lower testosterone and 29% (4%, 61%) of higher progesterone. Substituting 30 min of light physical activity for sedentary behavior was associated with 13% (-22%, -2%) of lower progesterone. Among girls, 30 min of additional sedentary behavior was associated with 8% (-15%, 0%) of lower testosterone and 24% (8%, 42%) of higher progesterone concentrations. Substituting 30 min of moderate physical activity for sedentary behavior was associated with 15% (0%, 31%) of higher cortisol, whereas substituting the same amount of light physical activity for sedentary behavior was associated with 22% (-39%, 0%) of lower progesterone. Substituting 30 min of vigorous physical activity for sedentary behavior per day was associated with almost six times higher levels (5.83, 95% confidence interval = 1.79-9.86) of HSD11B2 methylation in boys.

CONCLUSIONS

Accelerometer-measured daily physical activity was associated with reproductive hormones and HSD11B2 DNA methylation, differed by sex and activity intensity levels.

Objective and Self-Reported Measures of Physical Activity and Sex Hormones: Women's Lifestyle Validation Study

Background: The relationship between specific characteristics of physical activity (PA) (eg, intensity, type, frequency) with sex hormones is uncertain. The authors evaluated the association between characteristics of PA and circulating sex hormones. Methods: This was a cross-sectional analysis of the Women's Lifestyle Validation Study (n = 493). Total PA, light-intensity PA (LPA), and moderate- to vigorous-intensity PA (MVPA) were assessed by accelerometry (a) and self-report (sr). Self-report was used to assess PA type (ie, aerobic, weight training) and exercise frequency. Dehydroepiandrosterone sulfate, testosterone, and sex hormone-binding globulin (SHBG) were assayed among all women; estradiol was assayed in postmenopausal women not currently on hormone therapy. Results: Estradiol was inversely associated and SHBG positively associated with MVPA and LPA (estradiol: β = -0.15 per SD increase, P ≤ .01 for a-MVPA and a-LPA; SHBG: a-MVPA β = 0.20 per SD increase, P ≤ .01, a-LPA β = 0.15, P < .01). By type, aerobic activity and weight training were each independently associated with estradiol and SHBG. Controlling for body mass index attenuated all associations for estradiol, and to a lesser extent SHBG. PA was not associated with testosterone levels. Conclusions: Multiple aspects of PA were independently associated with sex hormones; associations varied some by activity intensity and type, and were attenuated after accounting for body mass index.

Association between circulating endogenous androgens and insulin sensitivity changes with exercise training in midlife women

OBJECTIVE

Aging induces a shift in circulating hormones in women, accompanied by weight gain during the late reproductive, menopausal transition, and postmenopausal years. Exercise has been shown to counter weight gain; however, it might increase circulating androgens. A 6-month aerobic and resistance training exercise regimen was implemented to examine interrelationships between circulating sex hormones, body composition, aerobic capacity, insulin sensitivity, and insulin resistance.

METHODS

Twenty-eight women, aged 42 to 52 years, completed the 6-month intervention study. They were randomly assigned to either a control (CON; n = 10) group-and maintained their sedentary lifestyle-or an exercise intervention (EXE; n = 18) group. The exercise intervention consisted of combined aerobic and resistance workouts scheduled 6 days/week for 60 minutes/day. Body weight, composition, VO2 peak, plasma insulin, glucose, lipid profile, estradiol, testosterone, progesterone, dehydroepiandrosterone, and dehydroepiandrosterone sulfate (DHEAS) were measured at baseline and on month 6. Insulin sensitivity was estimated using the insulin sensitivity index and the quantitative insulin sensitivity check index, whereas insulin resistance was estimated using the homeostatic model for insulin resistance.

RESULTS

There was a trend toward increased DHEAS in both groups (P < 0.1), but not as a function of the intervention. Insulin sensitivity index increased in the EXE group compared with the CON group (P < 0.01). Multiple linear regression indicated that, at 6 months, DHEAS was a negative contributor to insulin sensitivity in the EXE group, but not in the CON group.

CONCLUSIONS

In midlife women, an increase in circulating DHEAS, such as that previously reported during the menopausal transition, is associated with higher insulin resistance, but exercise can mitigate this risk by improving insulin sensitivity, thereby countering the effects of DHEAS.

Design of the SHAPE-2 study: the effect of physical activity, in addition to weight loss, on biomarkers of postmenopausal breast cancer risk

Background

Physical inactivity and overweight are two known risk factors for postmenopausal breast cancer. Former exercise intervention studies showed that physical activity influences sex hormone levels, known to be related to postmenopausal breast cancer, mainly when concordant loss of body weight was achieved. The question remains whether there is an additional beneficial effect of physical activity when weight loss is reached.

The aim of this study is to investigate the effect attributable to exercise on postmenopausal breast cancer risk biomarkers, when equivalent weight loss is achieved compared with diet-induced weight loss.

Design

The SHAPE-2 study is a three-armed, multicentre trial. 243 sedentary, postmenopausal women who are overweight or obese (BMI 25–35 kg/m²) are enrolled. After a 4-6 week run-in period, wherein a baseline diet is prescribed, women are randomly allocated to (1) a diet group, (2) an exercise group or (3) a control group. The aim of both intervention groups is to lose an amount of 5–6 kg body weight in 10–14 weeks. The diet group follows an energy restricted diet and maintains the habitual physical activity level. The exercise group participates in a 16-week endurance and strength training programme of 4 hours per week. Furthermore, they are prescribed a moderate caloric restriction. The control group is asked to maintain body weight and continue the run-in baseline diet.

Measurements include blood sampling, questionnaires, anthropometrics (weight, height, waist and hip circumference), maximal cycle exercise test (VO_2peak), DEXA-scan (body composition) and abdominal MRI (subcutaneous and visceral fat). Primary outcomes are serum levels of oestradiol, oestrone, testosterone and sex hormone binding globulin (SHBG).

Discussion

This study will give insight in the potential attributable effect of physical activity on breast cancer risk biomarkers and whether this effect is mediated by changes in body composition, in postmenopausal women. Eventually this may lead to the design of specific lifestyle guidelines for prevention of breast cancer.

Trial registration

The SHAPE-2 study is registered in the register of clinicaltrials.gov, Identifier: NCT01511276.

Estrogen replacement and skeletal muscle: mechanisms and population health

There is a growing body of information supporting the beneficial effects of estrogen and estrogen-based hormone therapy (HT) on maintenance and enhancement of muscle mass, strength, and connective tissue. These effects are also evident in enhanced recovery from muscle atrophy or damage and have significant implications particularly for the muscular health of postmenopausal women. Evidence suggests that HT will also help maintain or increase muscle mass, improve postatrophy muscle recovery, and enhance muscle strength in aged females. This is important because this population, in particular, is at risk for a rapid onset of frailty. The potential benefits of estrogen and HT relative to skeletal muscle function and composition combined with other health-related enhancements associated with reduced risk of cardiovascular events, overall mortality, and metabolic dysfunction, as well as enhanced cognition and bone health cumulate in a strong argument for more widespread and prolonged consideration of HT if started proximal to menopausal onset in most women. Earlier reports of increased health risks with HT use in postmenopausal women has led to a decline in HT use. However, recent reevaluation regarding the health effects of HT indicates a general lack of risks and a number of significant health benefits of HT use when initiated at the onset of menopause. Although further research is still needed to fully delineate its mechanisms of action, the general use of HT by postmenopausal women, to enhance muscle mass and strength, as well as overall health, with initiation soon after the onset of menopause should be considered.

Executive summary of the Stages of Reproductive Aging Workshop + 10: addressing the unfinished agenda of staging reproductive aging

OBJECTIVE

The aim of this article is to summarize the recommended updates to the 2001 Stages of Reproductive Aging Workshop (STRAW) criteria. The 2011 STRAW + 10 reviewed advances in understanding of the critical changes in hypothalamic-pituitary-ovarian function that occur before and after the final menstrual period.

METHODS

Scientists from five countries and multiple disciplines evaluated data from cohort studies of midlife women and in the context of chronic illness and endocrine disorders on change in menstrual, endocrine, and ovarian markers of reproductive aging including antimüllerian hormone, inhibin-B, follicle-stimulating hormone, and antral follicle count. Modifications were adopted by consensus.

RESULTS

STRAW + 10 simplified bleeding criteria for the early and late menopausal transition, recommended modifications to criteria for the late reproductive stage (Stage -3) and the early postmenopause stage (Stage +1), provided information on the duration of the late transition (Stage -1) and early postmenopause (Stage +1), and recommended application regardless of women's age, ethnicity, body size, or lifestyle characteristics.

CONCLUSIONS

STRAW + 10 provides a more comprehensive basis for assessing reproductive aging in research and clinical contexts. Application of the STRAW + 10 staging system should improve comparability of studies of midlife women and facilitate clinical decision making. Nonetheless, important knowledge gaps persist, and seven research priorities are identified.

Executive summary of the Stages of Reproductive Aging Workshop + 10: addressing the unfinished agenda of staging reproductive aging

OBJECTIVE

The aim of this article is to summarize the recommended updates to the 2001 Stages of Reproductive Aging Workshop (STRAW) criteria. The 2011 STRAW + 10 reviewed advances in understanding of the critical changes in hypothalamic-pituitary-ovarian function that occur before and after the final menstrual period.

METHODS

Scientists from five countries and multiple disciplines evaluated data from cohort studies of midlife women and in the context of chronic illness and endocrine disorders on change in menstrual, endocrine, and ovarian markers of reproductive aging including antimüllerian hormone, inhibin-B, follicle-stimulating hormone, and antral follicle count. Modifications were adopted by consensus.

RESULTS

STRAW + 10 simplified bleeding criteria for the early and late menopausal transition, recommended modifications to criteria for the late reproductive stage (Stage -3) and the early postmenopause stage (Stage +1), provided information on the duration of the late transition (Stage -1) and early postmenopause (Stage +1), and recommended application regardless of women's age, ethnicity, body size, or lifestyle characteristics.

CONCLUSIONS

STRAW + 10 provides a more comprehensive basis for assessing reproductive aging in research and clinical contexts. Application of the STRAW + 10 staging system should improve comparability of studies of midlife women and facilitate clinical decision making. Nonetheless, important knowledge gaps persist, and seven research priorities are identified.

Executive summary of the Stages of Reproductive Aging Workshop + 10: addressing the unfinished agenda of staging reproductive aging

OBJECTIVE

The aim of this article is to summarize the recommended updates to the 2001 Stages of Reproductive Aging Workshop (STRAW) criteria. The 2011 STRAW + 10 reviewed advances in understanding of the critical changes in hypothalamic-pituitary-ovarian function that occur before and after the final menstrual period.

METHOD(S)

Scientists from five countries and multiple disciplines evaluated data from cohort studies of midlife women and in the context of chronic illness and endocrine disorders on change in menstrual, endocrine, and ovarian markers of reproductive aging including antimüllerian hormone, inhibin-B, follicle-stimulating hormone, and antral follicle count. Modifications were adopted by consensus.

RESULT(S)

STRAW + 10 simplified bleeding criteria for the early and late menopausal transition, recommended modifications to criteria for the late reproductive stage (Stage -3) and the early postmenopause stage (Stage +1), provided information on the duration of the late transition (Stage -1) and early postmenopause (Stage +1), and recommended application regardless of women's age, ethnicity, body size, or lifestyle characteristics.

CONCLUSION(S)

STRAW + 10 provides a more comprehensive basis for assessing reproductive aging in research and clinical contexts. Application of the STRAW + 10 staging system should improve comparability of studies of midlife women and facilitate clinical decision making. Nonetheless, important knowledge gaps persist, and seven research priorities are identified.

Executive summary of the Stages of Reproductive Aging Workshop +10: addressing the unfinished agenda of staging reproductive aging

OBJECTIVE

The aim of this article is to summarize the recommended updates to the 2001 Stages of Reproductive Aging Workshop (STRAW) criteria. The 2011 STRAW +10 reviewed advances in understanding of the critical changes in hypothalamic-pituitary-ovarian function that occur before and after the final menstrual period.

METHODS

Scientists from five countries and multiple disciplines evaluated data from cohort studies of midlife women and in the context of chronic illness and endocrine disorders on change in menstrual, endocrine, and ovarian markers of reproductive aging including antimüllerian hormone, inhibin-B, follicle-stimulating hormone, and antral follicle count. Modifications were adopted by consensus.

RESULTS

STRAW +10 simplified bleeding criteria for the early and late menopausal transition, recommended modifications to criteria for the late reproductive stage (Stage -3) and the early postmenopause stage (Stage +1), provided information on the duration of the late transition (Stage -1) and early postmenopause (Stage +1), and recommended application regardless of women's age, ethnicity, body size, or lifestyle characteristics.

CONCLUSIONS

STRAW +10 provides a more comprehensive basis for assessing reproductive aging in research and clinical contexts. Application of the STRAW +10 staging system should improve comparability of studies of midlife women and facilitate clinical decision making. Nonetheless, important knowledge gaps persist, and seven research priorities are identified.

Effects of aerobic exercise on premenopausal sex hormone levels: results of the WISER study, a randomized clinical trial in healthy, sedentary, eumenorrheic women

BACKGROUND

It is hypothesized that exercise can lead to a decrease in breast cancer risk through several hormonal and nonhormonal mechanisms. The WISER (Women In Steady Exercise Research) study investigated the effects of aerobic exercise on premenopausal sex hormone levels.

METHODS

Three hundred ninety-one sedentary, healthy, young eumenorrheic women were randomized either into an exercise intervention of 30 minutes of aerobic exercise 5 times a week for approximately 16 weeks (n = 212) or into a control group (n = 179). Serum levels of estradiol, estrone sulfate, testosterone, and sex hormone-binding globulin (SHBG), all in the midfollicular phase, and of progesterone, in the midluteal phase, were measured at baseline and at the end of the 16-week period.

RESULTS

Compared with the controls (n = 153), exercisers (n = 166) experienced significant increases in aerobic fitness, lean body mass, and decreases in percent body fat. There were no significant changes in body weight and menstrual cycle length between or within groups. Progesterone decreased significantly in exercisers; however, this reduction was similar to that of the control group. No significant changes between or within groups were found for any of the other sex hormones or SHBG.

CONCLUSIONS

In premenopausal women, 16 weeks of 150 minutes per week of moderate aerobic exercise in young women did not significantly alter sex hormone or SHBG levels.

IMPACT

Any favorable effects that moderate aerobic exercise without an associated weight change may have on breast cancer risk in premenopausal women are unlikely to be a consequence of changes in levels of sex hormones or SHBG.

Physical activity and breast cancer prevention

Breast cancer is the most commonly diagnosed invasive malignancy and the second leading cause of cancer death in women. This chapter considers epidemiologic evidence regarding the association between physical activity and breast cancer risk from 73 studies conducted around the world. Across these studies there was a 25% average risk reduction amongst physically active women as compared to the least active women. The associations were strongest for recreational activity, for activity sustained over the lifetime or done after menopause, and for activity that is of moderate to vigorous intensity and performed regularly. There is also some evidence for a stronger effect of physical activity amongst postmenopausal women, women who are normal weight, have no family history of breast cancer, and are parous. It is likely that physical activity is associated with decreased breast cancer risk via multiple interrelated biologic pathways that may involve adiposity, sex hormones, insulin resistance, adipokines, and chronic inflammation. Future research should include prospective observational epidemiologic studies relating proposed biomarkers to breast cancer risk and also randomized controlled trials to examine how physical activity influences the proposed biomarkers. Exercise trials will provide more clarity regarding the appropriate type, dose, and timing of activity that relate to breast cancer risk reduction.

Longitudinal, epidemiologic studies of female reproductive aging

Human female reproductive aging consists of multiple processes and interacts with other physiological systems in unique ways. Here we discuss eight recent longitudinal, epidemiologic studies of female reproductive aging that include endocrine data to highlight their contributions to our understanding of these various aging processes and their interactions. Specifically, we review data on ovarian and nonovarian reproductive aging processes and reproductive staging. We consider these data in the context of longitudinal research design and research goals, identify limitations of the studies but also ways in which existing longitudinal data can further our understanding of aging processes, and make recommendations for future studies of female reproductive aging.

Alberta physical activity and breast cancer prevention trial: sex hormone changes in a year-long exercise intervention among postmenopausal women

PURPOSE

We examined how an aerobic exercise intervention influenced circulating estradiol, estrone, sex hormone-binding globulin (SHBG), androstenedione, and testosterone levels, which may be involved in the association between physical activity and breast cancer risk.

METHODS

A two-center, two-arm randomized controlled trial of exercise was conducted in 320 postmenopausal, sedentary women age 50 to 74 years. Participants were randomly assigned to a 1-year aerobic exercise intervention of 225 min/wk (n = 160) or to a control group who maintained their usual level of activity (n = 160). Baseline, 6-month, and 12-month assessments of estrone, estradiol, androstenedione, and testosterone were quantified by radioimmunoassay after extraction, and SHBG was quantified by an immunometric assay. Intent-to-treat analyses were performed using linear mixed models.

RESULTS

Blood data were available on 309 women (96.6%) at 12 months. Women in the intervention group exercised an average of 3.6 d/wk for 178 min/wk. At 12 months, statistically significant reductions in estradiol (treatment effect ratio [TER] = 0.93; 95% CI, 0.88 to 0.98) and free estradiol (TER = 0.91; 95% CI, 0.87 to 0.96) and increases in SHBG (TER = 1.04; 95% CI, 1.02 to 1.07) were observed in the exercise group compared with the control group. No significant differences in estrone, androstenedione, and testosterone levels were observed between exercisers and controls at 12 months.

CONCLUSION

This trial found that previously sedentary postmenopausal women can adhere to a moderate- to vigorous-intensity exercise program that results in changes in estradiol and SHBG concentrations that are consistent with a lower risk for postmenopausal breast cancer.

Recreational physical activity and steroid hormone levels in postmenopausal women

Recreational physical activity has been both positively and inversely associated with cancer risk for postmenopausal women, acting presumably through hormonal mechanisms. Relatively little is known about the effects of exercise on postmenopausal steroid hormone levels. The authors evaluated the association between recreational activity and plasma steroid hormones among 623 US healthy, postmenopausal women in the Nurses' Health Study not using exogenous hormones at the time of blood draw (1989-1990). Participants self-reported recreational physical activity by questionnaire in 1986, 1988, and 1992. Plasma samples were assayed for estrogens, androgens, and sex hormone-binding globulin. Geometric mean hormone levels adjusted and not adjusted for body mass index were calculated. In general, estrogen and androgen levels were lower in the most- and the least-active women compared with those reporting moderate activity, suggesting a U-shaped relation. For example, estrone sulfate levels in quintiles 1-5 of metabolic equivalent task-hours were 197, 209, 222, 214, and 195 pg/mL, respectively. Tests for nonlinearity using polynomial regression were significant for several estrogens, androgens, and sex hormone-binding globulin (2-sided P <or= 0.01). These results suggest the possibility of a nonlinear relation between recreational physical activity and hormone levels in postmenopausal women.

Long-term and recent recreational physical activity and survival after breast cancer: the California Teachers Study

INTRODUCTION

Long-term physical activity is associated with lower breast cancer risk. Little information exists on its association with subsequent survival.

METHODS

California Teachers Study cohort members provided information in 1995-1996 on long-term (high school through age 54 years) and recent (past 3 years) participation in moderate and strenuous recreational physical activities. The 3,539 women diagnosed with invasive breast cancer after cohort entry and through December 31, 2004, were followed through December 31, 2005. Of these, 460 women died, 221 from breast cancer. Moderate and strenuous physical activities were combined into low (<or=0.50 h/wk/y of any activity), intermediate (0.51-3.0 h/wk/y of moderate or strenuous activity but no activity >3.0 h/wk/y), or high activity (>3.0 h/wk/y of either activity type). Multivariable relative risks (RR) and 95% confidence intervals (95% CI) for mortality were estimated using Cox proportional hazards methods, adjusting for race/ethnicity, estrogen receptor status, disease stage, and baseline information on comorbidities, body mass index, and caloric intake.

RESULTS

Women with high or intermediate levels of long-term physical activity had lower risk of breast cancer death (RR, 0.53; 95% CI, 0.35-0.80; and RR, 0.65; 95% CI, 0.45-0.93, respectively) than women with low activity levels. These associations were consistent across estrogen receptor status and disease stage, but were confined to overweight women. Deaths due to causes other than breast cancer were related only to recent activity.

CONCLUSIONS

Consistent long-term participation in physical activity before breast cancer diagnosis may lower risk of breast cancer death, providing further justification for public health strategies to increase physical activity throughout the lifespan.

Relationship between higher estradiol levels and 9-year mortality in older women: the Invecchiare in Chianti study

OBJECTIVES

To investigate the relationship between total estradiol (E2) levels and 9-year mortality in older postmenopausal women not taking hormone replacement therapy (HRT).

DESIGN

Population-based study of persons living in the Chianti geographic area (Tuscany, Italy).

SETTING

Community.

PARTICIPANTS

A representative sample of 509 women aged 65 and older with measures of total E2.

MEASUREMENTS

Serum total E2 was measured at the University of Parma using ultrasensitive radioimmunoassay (RIA).

RESULTS

Women who died (n=135) during 9 years of follow up were older; had higher total E2 levels; and were more likely to have evidence of stroke, hypertension, diabetes mellitus, and congestive heart failure at baseline than survivors. Higher E2 levels were associated with a greater likelihood of death (hazard ratio (HR)=1.03, 95% confidence interval (CI)=1.01-1.06), and the relationship was independent of age, waist:hip ratio, C-reactive protein, education, cognitive function, physical activity, caloric intake, smoking, and chronic disease (HR=1.08 pg/mL, 95% CI=1.03-1.13, P=.003). The excessive risk of death associated with higher total E2 was not attenuated after adjustment for total testosterone (HR=1.12, 95% CI=1.02-1.18, P<.001) and after further adjustment for insulin resistance evaluated using the homeostasis model assessment (HR=1.07, 95% CI=1.03-1.17, P<.001). Total E2 was highly predictive of death after more than 5 years (HR=1.42: CI 1.01-1.91, P=.04) and not predictive of death for less than 5 years (P=.78).

CONCLUSION

Higher total E2 concentration predicts mortality in older women not taking HRT.

Physical activity and endogenous sex hormone levels in postmenopausal women: a cross-sectional study in the Prospect-EPIC Cohort

BACKGROUND

The protective effect of physical activity on breast cancer risk might be mediated by sex hormone levels. In this study, we examined the association between usual physical activity and plasma levels of estrogens, androgens, dehydroepiandrosterone sulphate (DHEAS), and sex hormone binding globulin (SHBG) in postmenopausal women.

METHODS

We conducted a cross-sectional study among 806 postmenopausal women participating in the Prospect-EPIC study. Usual physical activity was assessed using a short questionnaire and summarized into a simple, validated four-level index. This index combines occupational physical activity with time spent on cycling and sporting. Levels of estrone, estradiol, androstenedione, DHEAS, testosterone, and SHBG were measured in plasma. General linear models were used to examine the association between usual physical activity and sex hormone levels, adjusted for confounders.

RESULTS

We observed an inverse association between physical activity and estradiol levels (free: inactive, 0.26 pg/mL; active, 0.23 pg/mL; P-trend = 0.045; total: inactive, 8.8 pg/mL; active, 8.0 pg/mL; P-trend = 0.08) and a positive association between physical activity and SHBG (inactive, 15.1 nmol/L; active, 19.3 nmol/L; P-trend = 0.05). These associations could largely be explained by the effects of sporting. We also observed a positive association between physical activity and DHEAS (inactive, 352.4 ng/mL; active, 460.3 ng/mL; P-trend = 0.01).

CONCLUSIONS

Our results are in accordance with the hypothesis that usual physical activity decreases estradiol levels and increases SHBG. We also found that high levels of physical activity are associated with high levels of DHEAS. Furthermore, our results suggest that vigorous forms of physical activity influence sex hormone levels most.