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Mammographic density change with 1 year of aerobic exercise among postmenopausal women: a randomized controlled trial.

ABSTRACT: The Alberta Physical Activity and Breast Cancer Prevention (ALPHA) Trial examined the influence of aerobic exercise on biological factors that are associated with breast cancer risk. Mammographic density, a secondary outcome, is reported here.The ALPHA Trial was a parallel group randomized controlled trial conducted between May 2003 and July 2007. Postmenopausal, sedentary women ages 50 to 74 years (n = 320) were evenly randomized to aerobic exercise (45 minutes, 5 days per week) or control (usual life-style) for 1 year. Dense fibroglandular tissue and nondense fatty tissue were measured from mammograms at baseline and 1 year using computer-assisted thresholding software for area measurements and a new technique that relies on the calibration of mammography units with a tissue-equivalent phantom for volumetric measurements.Nondense volume decreased in the exercise group relative to the control group (difference between groups = -38.5 cm(3); 95% confidence interval, -61.6 to 15.4; P = 0.001). Changes in total body fat accounted for this decrease. Changes in dense area and dense volume, measures that have previously been associated with breast cancer risk, were not significantly different between the groups (P > or = 0.26).Achieving changes in mammographic measures may require more exercise or a study population with higher baseline levels of sex hormones or a wider range of mammographic density. The data from this study, however, suggest that the protective effect of exercise on breast cancer risk may operate through a mechanism other than mammographic density.

SUBMITTER: Woolcott CG

PROVIDER: S-EPMC2945907 | biostudies-literature | 2010 Apr

REPOSITORIES: biostudies-literature

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Mammographic density change with 1 year of aerobic exercise among postmenopausal women: a randomized controlled trial.

Woolcott Christy G CG Courneya Kerry S KS Boyd Norman F NF Yaffe Martin J MJ Terry Tim T McTiernan Anne A Brant Rollin R Ballard-Barbash Rachel R Irwin Melinda L ML Jones Charlotte A CA Brar Sony S Campbell Kristin L KL McNeely Margaret L ML Karvinen Kristina H KH Friedenreich Christine M CM

Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology 20100323 4

<h4>Background</h4>The Alberta Physical Activity and Breast Cancer Prevention (ALPHA) Trial examined the influence of aerobic exercise on biological factors that are associated with breast cancer risk. Mammographic density, a secondary outcome, is reported here.<h4>Methods</h4>The ALPHA Trial was a parallel group randomized controlled trial conducted between May 2003 and July 2007. Postmenopausal, sedentary women ages 50 to 74 years (n = 320) were evenly randomized to aerobic exercise (45 minute ...[more]

PMID: 20332266

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Project description:Despite the clear health benefits of exercise, exercised-induced weight loss is often less than expected. The term 'exercise energy compensation' is used to define the amount of weight loss below what is expected for the amount of exercise energy expenditure. We examined the dose-response effects of exercise volume on energy compensation in postmenopausal women.Data from Alberta Physical Activity and Breast Cancer Prevention (ALPHA) and Breast Cancer and Exercise Trial in Alberta (BETA) were combined for the present analysis. The ALPHA and BETA trials were two-centred, two-armed, 12-month randomized controlled trials. The ALPHA trial included 160 participants randomized to 225 min per week of aerobic exercise, and the BETA trial randomized 200 participants to each 150 and 300 min per week of aerobic exercise. All participants were aged 50-74 years, moderately inactive (<90 min per week of exercise), had no previous cancer diagnosis and a body mass index between 22 and 40 kg m-2. Energy compensation was based on changes in body composition (dual-energy X-ray absorptiometry scan) and estimated exercise energy expenditure from completed exercise volume. Associations between Δenergy intake, ΔVO2peak and Δphysical activity time with energy compensation were assessed.No differences in energy compensation were noted between interventions. However, there were large inter-individual differences in energy compensation between participants; 9.4% experienced body composition changes that were greater than expected based on exercise energy expenditure, 64% experienced some degree of energy compensation and 26.6% experienced weight gain based on exercise energy expenditure. Increases in VO2peak were associated with reductions in energy compensation (β=-3.44 ml kg-1 min-1, 95% confidence interval for β=-4.71 to -2.17 ml kg-1 min-1; P=0.0001).Large inter-individual differences in energy compensation were noted, despite no differences between activity doses. In addition, increases in VO2peak were associated with lower energy compensation. Future studies are needed to identify behavioral and metabolic factors that may contribute to this large inter-individual variability in energy compensation.

Project description:BackgroundPhysical activity has emerged as an important lifestyle factor for primary prevention of numerous diseases, including postmenopausal breast cancer. No study to date has assessed the acute and long-term effects of year-long aerobic exercise programs differing in prescribed exercise volume on physical activity and sedentary time in postmenopausal women. Therefore, we aimed to examine the effects of two moderate-vigorous intensity exercise doses on total, light and moderate-vigorous intensity physical activity times, and sedentary time in postmenopausal women during the year-long intervention and one year later.MethodsThe Breast Cancer and Exercise Trial in Alberta (BETA) was a two-center, two-arm, 12-month randomized controlled trial that included 400 previously inactive postmenopausal women randomized to either 150 (MODERATE) or 300 (HIGH) minutes/week of aerobic exercise. Physical activity and sedentary time were assessed at baseline, 6- (intervention mid-point), 12- (prior to end of intervention) and 24-months (follow-up) with waist-mounted accelerometers (Actigraph GTX3®). Self-reported activity and sedentary time at baseline, 12- and 24-months was also assessed (Past Year Total Physical Activity Questionnaire and SIT-Q). Intention-to-treat analyses were conducted using linear mixed models and adjusted for baseline variables.ResultsBoth physical activity interventions led to increases in objective and subjective measures of total and moderate-vigorous intensity/recreational physical activity time, coupled with decreases in sedentary time, at 6- and 12-months compared to baseline. Additionally, greater increases in accelerometry-derived total physical activity time at 6- and 12-months, and self-reported recreational activity time at 12-months, compared to baseline were noted in the HIGH versus MODERATE groups. Decreases in total, light and moderate-vigorous intensity physical activity time, and an increase in sedentary time, in both groups were noted at 24-months compared to 12-months. A decrease in light intensity physical activity time in both groups at 24-months compared to baseline was also noted.ConclusionThese findings have important health implications, suggesting that total physical activity time can be increased with greater volumes of prescribed exercise, but that additional support and resources could be used to promote the maintenance of these high levels of aerobic exercise participation following study completion.Trial registrationclinicaltrials.gov identifier: NCT01435005 (BETA Trial). Registred September 15th 2011 (retrospectively registered).

Project description:Mammographic breast density (MBD) is a risk factor for breast cancer, but its molecular basis is poorly understood. Growth factors stimulate cellular and epithelial proliferation and could influence MBD via these mechanisms. Studies investigating the associations of circulating growth factors with MBD have, however, yielded conflicting results especially in postmenopausal women. We, therefore, investigated the associations of plasma growth factor gene expression [insulin-like growth factor (IGF)-1, IGF-binding protein 3, FGF-1, FGF-12, TGFβ1 and bone morphogenetic protein (BMP)-2] with MBD in postmenopausal women. We used NanoString nCounter platform to quantify plasma growth factor gene expression and Volpara to evaluate volumetric MBD measures. We investigated the associations of growth factor gene expression with MBD using both multiple linear regression (fold change) and multinomial logistic regression models, adjusted for potential confounders. The mean age of the 368 women enrolled was 58 years (range, 50-64). In analyses using linear regression models, one unit increase in IGF-1 gene expression was associated with a 35% higher volumetric percent density (VPD, 1.35; 95% confidence interval (CI), 1.13-1.60; P = 0.001). There were suggestions that TGFβ1 gene expression was positively associated with VPD while BMP-2 gene expression was inversely associated with VPD, but these were not statistically significant. In analyses using multinomial logistic regression, TGFβ1 gene expression was 33% higher (OR = 1.33; 95% CI, 1.13-1.56; P = 0.0008) in women with extremely dense breasts than those with almost entirely fatty breasts. There were no associations between growth factor gene expression and dense volume or nondense volume. Our study provides insights into the associations of growth factors with MBD in postmenopausal women and requires confirmation in other study populations.Prevention relevanceMammographic breast density is a strong risk factor for breast cancer. Understanding its underlying biological mechanisms could have utility in breast cancer prevention.

Project description:BackgroundPostmenopausal smokers have difficulty quitting smoking and experience considerable weight gain with smoking cessation. We examined whether adjunctive smoking treatment with exercise, compared to a relaxation control condition, could improve cigarette abstinence, decrease cigarettes smoked per day (CPD), and ameliorate changes in body mass index (BMI) in postmenopausal smokers.MethodsWomen (N = 301) signed informed consent and were randomized to treatment at two sites (Universities of Connecticut and Minnesota). We randomized groups of participants to a comprehensive group treatment program that included 12 weeks of varenicline and either a moderate exercise or relaxation component for 6 months. Participants were followed for a year after medication treatment.ResultsOverall, 17.3% of patients reported carbon monoxide-verified continuous abstinence for the 9- to 12-week period, and 11.6% reported prolonged abstinence at 1 year, with no significant differences between treatment conditions. CPD reported at study visits showed significant main effects for time in weeks, for site, and for treatment. The Exercise condition reported smoking fewer CPD over time, and that advantage widened over time. In terms of BMI, significant effects for time in weeks, and for the interaction of Week × Treatment condition, reflected gradually increasing BMI in these women over time, but with the increase in BMI slower in the Exercise condition.ConclusionsExercise, compared to relaxation, was associated with a reduced BMI and CPD in postmenopausal women, but did not increase end of treatment or prolonged abstinence. Further research is needed to devise exercise programs that increase smoking cessation rates in postmenopausal women.ImplicationsThis study adds to the literature on the effectiveness of a moderate exercise intervention compared to a relaxation control condition as an adjunctive treatment for smoking cessation in postmenopausal women. Our exercise program did not increase end of treatment or prolonged abstinence rates in postmenopausal women; however, there was a beneficial effect on smoking reduction and reduced body mass index. Additional research is needed to devise exercise programs that increase smoking cessation rates in postmenopausal women.

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Mammographic density change with 1 year of aerobic exercise among postmenopausal women: a randomized controlled trial.

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Mammographic density change with 1 year of aerobic exercise among postmenopausal women: a randomized controlled trial.

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