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

ABSTRACT: 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.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.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.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.

SUBMITTER: Friedenreich CM

PROVIDER: S-EPMC2849767 | biostudies-literature | 2010 Mar

REPOSITORIES: biostudies-literature

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

Friedenreich Christine M CM Woolcott Christy G CG McTiernan Anne A Ballard-Barbash Rachel R Brant Rollin F RF Stanczyk Frank Z FZ Terry Tim T Boyd Norman F NF Yaffe Martin J MJ Irwin Melinda L ML Jones Charlotte A CA Yasui Yutaka Y Campbell Kristin L KL McNeely Margaret L ML Karvinen Kristina H KH Wang Qinggang Q Courneya Kerry S KS

Journal of clinical oncology : official journal of the American Society of Clinical Oncology 20100216 9

<h4>Purpose</h4>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.<h4>Methods</h4>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 interve ...[more]

PMID: 20159820

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Project description:Title: Transcriptome analysis of human endometrial tissues from healthy post-menoupausal women reflecting the endometrial response to 3-weeks treatment with tibolone, E2 and E2+MPA. In an observational, open, non-randomized, controlled study uterine tissues were collected in order to generate endometrial gene expression profiles. healthy postmenopausal women were enrolled into the following treatment groups: Control-group; Tibolone-group, 2,5 mg of tibolone (administered orally) every day, starting 21 days prior to surgery; Estradiol-group, 2 mg of estradiol (administered orally) every day, starting 21 days prior to surgery; Estradiol+progestagen-group, 2 mg of estradiol (administered orally) and 5 mg of MPA (Medroxy Progesteroneacetate, administered orally) every day, starting 21 days prior to surgery. Pure (100%) endometrium was isolated from the snap-frozen uterine tissues and used for RNA isolation. RNA was labeled and hybridized to whole genome Affymetrix U133plus2 GeneChips containing 54,614 probe sets, representing approximately 47,000 transcripts. Relative to the control group, 940 genes are regulated in the endometrium of E2 treated patients, whereas only 198 genes are significantly regulated in endometria from tibolone or E2+MPA treated patients. Furthermore, only 9% of E2 regulated genes are also regulated by tibolone (85 out of 940), only 5% are also regulated by E2+MPA treatment and the overlap between tibolone and E2+MPA treatment is about 10%. This indicated that tibolone-treatment results in a weak endometrial profile similarity to E2 treatment and no profile similarity to E2+MPA treatment. A more detailed analysis showed that down stream processes, such as regulation of the cell cycle, angiogenesis and cell proliferation are almost not affected by tibolone treatment but, in contrast, are significantly affected by E2. For example, upon staining with Ki67, a marker for mitotic activity, significantly increased stromal as well as glandular cell proliferation was observed in the endometria from the E2-only treated group, while tibolone treatment resulted only in a slight increase in stromal cell proliferation (and no increase in glandular cell proliferation). These results indicate that in contrast to long-term tibolone use, short-term (21-days) use results in some estrogenic stimulation of the endometrium, which is clearly far less and rather different from what is observed during E2 treatment. References: Klaassens et al., 2006 Hanifi-Moghaddam et al., 2007 Verheul et al., 2007

Project description:Few studies have examined recreational physical activity (RPA) after participating in a structured exercise intervention. More specifically, little is known about the long-term effects of exercise interventions in post-menopausal women. This study had two objectives: 1) To compare RPA in postmenopausal women in the exercise group and the control group 12 months after the end of the Alberta Physical Activity and Breast Cancer Prevention (ALPHA) Trial; and 2) To apply the Theory of Planned Behaviour (TPB) to identify predictors of RPA 12 months post-intervention among women in the exercise group.Self-reported RPA 12-months post-intervention from a validated questionnaire was used to estimate RPA levels for control group (118/160, 74% response) and exercise group participants (126/160, 79% response). Bivariate analysis was used to compare RPA between exercise and control group participants and to identify TPB variables for multivariate analysis. Logistic regression was applied to TPB data collected from self- administered questionnaires at end of trial by exercise group participants (126/160, 79% response) to identify predictors of long-term RPA.At 12 months post-intervention, 62% of women in the exercise group were active compared to 58% of controls (p?=?0.52). Of the TPB constructs examined, self-efficacy (OR =2.98 (1.08-8.20)) and behavioural beliefs (OR?=?1.46 (1.03-2.06)) were identified as predictors of RPA for exercise group participants.Levels of RPA in the exercise and control groups were comparable 12 months post intervention, indicating that participation in the ALPHA trial was associated with increased physical activity in previously inactive women, regardless of randomization into either the exercise group or in the control group. Exercise interventions that promote self-efficacy and positive behavioural beliefs have the potential to have long-term impacts on physical activity behaviour, although further research is needed to examine additional psychological, social and environmental predictors of long-term RPA in post-menopausal women.ClinicalTrials.gov NCT00522262.

Dataset Information

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

Publications

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

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