Population attributable risk for breast cancer: Diet, nutrition, and physical exercise

Background: The percentages of breast cancer cases in a given population attributable to specific risk factors (i.e., the population-attributable risks) can be calculated; determination of such risks associated with potentially modifiable risks factors, such as diet (e.g., levels of consumption of fruits, vegetables, vitamins, etc.), alcohol consumption, exercise, and body weight, are necessary to focus prevention strategies. Methods: With the use of data from a case-control study conducted in Italy from June 1991 through April 1994 on 2569 breast cancer case subjects and 2588 control subjects, we calculated multivariate odds ratios and population- attributable risks for breast cancer in relation to dietary β-carotene and vitamin E intake, alcohol consumption, physical activity, and, for postmenopausal women, body mass index. Results: Among all subjects, the following attributable risks for the indicated risk factors were observed: 10.7% (95% confidence interval [CI] = 4.4%-17.0%) for high alcohol intake (i.e., >20 g/day), 15.0% (95% CI = 7.4%-22.9%) for low β-carotene intake (i.e.,