American Journal of Epidemiology Advance Access published online on June 13, 2008
American Journal of Epidemiology, doi:10.1093/aje/kwn143
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Original Contribution |
Proportion of Invasive Breast Cancer Attributable to Risk Factors Modifiable after Menopause
1 Department of Population Health Sciences, University of Wisconsin-Madison, Madison, WI
2 University of Wisconsin Paul P. Carbone Comprehensive Cancer Center, Madison, WI
3 Division of Cancer Prevention and Control, H. Lee Moffitt Cancer Center & Research Institute, Tampa, FL
4 Dartmouth Medical School, Norris Cotton Cancer Center, Lebanon, NH
5 Cancer Prevention Program, Fred Hutchinson Cancer Research Center, Seattle, WA
Correspondence to Dr. Amy Trentham-Dietz, Department of Population Health Sciences, University of Wisconsin-Madison, 610 Walnut Street, WARF Room 701, Madison, WI 53726 (e-mail: trentham{at}wisc.edu).
Received for publication January 25, 2008. Accepted for publication May 2, 2008.
A number of breast cancer risk factors are modifiable later in life, yet the combined impact of the population changes in these risk factors on breast cancer incidence is not known to have been evaluated. The population attributable risk (PAR) associated with individual risk factors and the summary PAR for sets of modifiable and nonmodifiable risk factors were estimated by using data on 3,499 invasive breast cancer cases and 4,213 controls from a population-based study in Wisconsin, Massachusetts, and New Hampshire, conducted from 1997 to 2001. The summary PAR for factors modifiable after menopause, including current postmenopausal hormone use, recent alcohol consumption, adult weight gain, and recent recreational physical activity, was 40.7%. Of the individual modifiable factors, the highest PARs were observed for weight gain (21.3%) and recreational physical activity (15.7%), which together showed a summary PAR of 33.6%. The summary PAR for factors not modifiable after menopause, including family history of breast cancer, personal history of benign breast disease, height at age 25 years, age at menarche, age at menopause, age at first birth, and parity, was 57.3%. These findings suggest that a substantial fraction of postmenopausal breast cancer may be avoided by purposeful changes in lifestyle later in life.
alcohol drinking; breast neoplasms; case-control studies; exercise; hormone replacement therapy; risk factors; weight gain
Abbreviations: PAR, population attributable risk