Original Article

International Journal of Obesity (2011) 35, 427–435; doi:10.1038/ijo.2010.147; published online 7 September 2010

Clinical Studies and Practice

Adiposity changes after a 1-year aerobic exercise intervention among postmenopausal women: a randomized controlled trial
Open

C M Friedenreich1, C G Woolcott2, A McTiernan3, T Terry4, R Brant5, R Ballard-Barbash6, M L Irwin7, C A Jones8, N F Boyd9, M J Yaffe10, K L Campbell11, M L McNeely12, K H Karvinen13 and K S Courneya14

  1. 1Department of Population Health Research, Alberta Health Services, Calgary, Alberta, Canada
  2. 2Cancer Research Center of Hawaii, University of Hawaii, Honolulu, HI, USA
  3. 3Prevention Center, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
  4. 4Division of Breast Imaging, Department of Oncologic Imaging, Cross Cancer Institute, Edmonton, Alberta, Canada
  5. 5Department of Statistics, University of British Columbia, Vancouver, British Columbia, Canada
  6. 6Applied Research Program, Division of Cancer Control and Population Sciences, National Cancer Institute, Bethesda, MD, USA
  7. 7Department of Epidemiology and Public Health, Yale University, New Haven, CT, USA
  8. 8Department of Medicine, University of Calgary, Calgary, Alberta, Canada
  9. 9Division of Epidemiology, Statistics and Behavioural Research, Ontario Cancer Institute, Toronto, Ontario, Canada
  10. 10Sunnybrook Research Institute, Toronto, Ontario, Canada
  11. 11Department of Physical Therapy, University of British Columbia, Vancouver, British Columbia, Canada
  12. 12Departments of Physical Therapy and Oncology, University of Alberta, Edmonton, Alberta, Canada
  13. 13Department of Exercise and Sports Science, East Carolina University, Greenville, NC, USA
  14. 14Faculty of Physical Education and Recreation, University of Alberta, Edmonton, Alberta, Canada

Correspondence: Dr CM Friedenreich, Department of Population Health Research, Alberta Health Services, 1331 29 Street NW, Calgary, Alberta, Canada T2N 4N2. E-mail: christine.friedenreich@albertahealthservices.ca

Received 28 January 2010; Revised 18 May 2010; Accepted 9 June 2010; Published online 7 September 2010.

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Abstract

Objective:

 

We examined the effects of an aerobic exercise intervention on adiposity outcomes that may be involved in the association between physical activity and breast cancer risk.

Design:

 

This study was a two-centre, two-armed, randomized controlled trial. The 1-year-long exercise intervention included 45min of moderate-to-vigorous aerobic exercise five times per week, with at least three of the sessions being facility based. The control group was asked not to change their activity and both groups were asked not to change their diet.

Subjects:

 

A total of 320 postmenopausal, sedentary, normal weight-to-obese women aged 50–74 years who were cancer-free, nondiabetic and nonhormone replacement therapy users were included in this study.

Measurements:

 

Anthropometric measurements of height, weight and waist and hip circumferences; dual energy X-ray absorptiometry measurements of total body fat; and computerized tomography measurements of abdominal adiposity were carried out.

Results:

 

Women in the exercise group exercised a mean of 3.6 days (s.d.=1.3) per week and 178.5min (s.d.=76.1) per week. Changes in all measures of adiposity favored exercisers relative to controls (P<0.001). The mean difference between groups was: −1.8kg for body weight; −2.0kg for total body fat; −14.9cm2 for intra-abdominal fat area; and −24.1cm2 for subcutaneous abdominal fat area. A linear trend of greater body fat loss with increasing volume of exercise was also observed.

Conclusion:

 

A 1-year aerobic exercise program consistent with current public health guidelines resulted in reduced adiposity levels in previously sedentary postmenopausal women at higher risk of breast cancer.

Keywords:

clinical trial; exercise; body weight; breast neoplasms; biological mechanisms

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