title: Energy balance and breast cancer risk.
abstract: We evaluated the hypothesis that a pattern of behavioral exposures indicating positive energy balance [i.e., less exercise/sport activity, high body mass index (BMI), or high energy intake] would be associated with an increased breast cancer risk in the Shanghai Breast Cancer Study, a population-based study of 1,459 incident breast cancer cases and 1,556 age frequency-matched controls. Participants completed in-person interviews that collected information on breast cancer risk factors, usual dietary intake and physical activity in adulthood. Anthropometric indices were measured. Odds ratios and 95% confidence intervals were estimated by logistic regression to describe the individual and joint effects of the exposures on breast cancer risk. Lack of exercise/sport activity, low occupational activity, and high BMI were all individually associated with increased risk of breast cancer [odds ratios (OR) ranged from 1.49 to 1.86]. In general, women with lower exercise/sport activity level and higher BMI, or those with higher energy intake, were at an increased risk compared with women who reported more exercise/sport activities, had lower BMIs, or reported less energy intake. There was a significant multiplicative interaction (P = 0.02) between adult exercise/sport activity and BMI, with inactive women in the upper BMI quartile being at increased risk (OR, 2.16; 95% confidence interval, 1.25-3.74) compared with their active and lean counterparts. This association was stronger in postmenopausal than in premenopausal women, and non-exercising postmenopausal women with higher BMIs were at substantially increased risk (OR, 4.74; 95% confidence interval, 2.05-12.20). Our study suggests that promotion of behavior patterns that optimize energy balance (weight control and increasing physical activity) may be a viable option for breast cancer prevention.
authors.affiliation: Department of Surgery, Meharry Medical College, 1005 Dr. D.B. Todd Boulevard, Nashville, Tennessee 37208, USA. amalin@mmc.edu
authors.forename: Alecia
authors.initials: A
authors.lastname: Malin
authors.forename: Charles E
authors.initials: CE
authors.lastname: Matthews
authors.forename: Xiao-Ou
authors.initials: XO
authors.lastname: Shu
authors.forename: Hui
authors.initials: H
authors.lastname: Cai
authors.forename: Qi
authors.initials: Q
authors.lastname: Dai
authors.forename: Fan
authors.initials: F
authors.lastname: Jin
authors.forename: Yu-Tang
authors.initials: YT
authors.lastname: Gao
authors.forename: Wei
authors.initials: W
authors.lastname: Zheng
mesh_terms: D000328:Adult; D015992:Body Mass Index; D001943:Breast Neoplasms / Q000453:epidemiology / Q000209:etiology* / Q000517:prevention & control*; D002681:China / Q000453:epidemiology; D004734:Energy Metabolism; D015444:Exercise; D005260:Female; D015438:Health Behavior; D006801:Humans; D008875:Middle Aged; D017698:Postmenopause; D017697:Premenopause; D012307:Risk Factors; D015431:Weight Loss