Breast Cancer
Conditions
Keywords
Physical activity, Sex steroid hormones, Breast cancer risk, Intervention study, Postmenopausal women
Brief summary
Purpose of the SHAPE study is to examine the effects of an 1-year exercise programme on endogenous hormone levels associated with breast cancer among sedentary postmenopausal women and whether a decrease in intra-abdominal fat is associated with a lowering of these hormone levels.
Detailed description
Physical activity has been associated with a decreased risk for breast cancer. The biological mechanism(s) underlying the association between physical activity and breast cancer is not clear. Most prominent hypothesis is that physical activity may protect against breast cancer through reduced lifetime exposure to endogenous hormones. Another hypothesis is that physical activity prevents overweight and abdominal adiposity. In this intervention study, 189 sedentary postmenopausal women who are aged 50-69 years are randomly allocated to an intervention or a control group. The intervention consists of an 1-year moderate-to-vigorous intensity aerobic and strength training exercise programme. Participants allocated to the control group are requested to retain their habitual exercise pattern. Primary study parameters measured at baseline, at four months and at 12 months are: serum concentrations of endogenous estrogens, endogenous androgens, sex hormone binding globulin and insulin. Other study parameters include: amount of total and abdominal fat, weight, BMI, body fat distribution, physical fitness, blood pressure and lifestyle factors. This study will contribute to the body of evidence relating physical activity and breast cancer risk and will provide insight into possible mechanisms through which physical activity might be associated with reduced risk of breast cancer in postmenopausal women.
Interventions
BEHAVIORALPhysical activity
Sponsors
National Institute for Public Health and the Environment (RIVM)
Dutch Cancer Society
UMC Utrecht
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
SINGLE
Eligibility
Sex/Gender
FEMALE
Age
50 Years to 69 Years
Healthy volunteers
Yes
Inclusion criteria
* Women aged 50 -69 year * \> 12 months since last menses * Non-smokers (at least 12 months) * Sedentary * Knowledge of the Dutch language * Agreement to be randomly assigned to either the exercise intervention or control group * Informed consent to participate in all screening and study activities
Exclusion criteria
* Use of hormone replacement or oral contraceptives in past 6 months * Morbidly obese (BMI \> 40) * BMI \< 22 * Currently on or planning to go on a strict diet * Ever diagnosed with breast cancer * Diagnosis of other types of cancer in the past 5 years * Diabetes mellitus or other endocrine related diseases * Disorders or diseases (locomotor, optical, neurological, mental) that might impede the participation in the exercise programme * Alcohol or drug abuse * Maintenance use of corticosteroids * Use of beta blockers
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Serum concentrations of endogenous estrogens: estradiol (total, free), estrone, estrone sulfate | — |
| Serum concentrations of endogenous androgens: testosterone, androstenedione | — |
| Serum concentrations of sex hormone binding globulin | — |
| Serum concentrations of fasting insulin | — |
| Insulin sensitivity | — |
Secondary
| Measure | Time frame |
|---|---|
| Physical Fitness | — |
| Blood pressure | — |
| Lifestyle parameters (covariates) | — |
| Exercise behaviour (habitual physical activity, past week activity, physical activity in the past) | — |
| Amount of total body fat and intra-abdominal fat | — |
| Alcohol consumption | — |
| Medication use | — |
| Reproductive factors | — |
| Medical history | — |
| Diet (daily caloric intake; percent daily calories from fat, carbohydrates and proteins) | — |
| Weight | — |
| Body Mass Index (BMI) | — |
| Body fat distribution | — |
| Waist to hip ratio | — |
Countries
Netherlands
Outcome results
None listed