Original Contribution Association of Childhood and Adolescent Anthropometric Factors, Physical Activity, and Diet with Adult Mammographic Breast Density

Early-life exposures may influence the development of breast cancer. The authors examined the association of childhood and adolescent anthropometric factors, physical activity levels, and diet with adult mammographic breast density, a strong risk factor for breast cancer. Women in the Minnesota Breast Cancer Family Study cohort who had undergone mammograms but had not had breast cancer (n 1,893) formed the sample. Information on adolescent exposures, including relative height, weight, and physical activity at ages 7, 12, and 18 years and diet at age 12–13 years, was self-reported during two follow-up studies (1990–2003). Mammographic percent density was estimated using a computer-assisted thresholding program. Statistical analyses were performed using linear mixed-effects models with two-sided tests. Positive associations with height at ages 7 (p < 0.001), 12 (p < 0.001), and 18 (p < 0.001) years and percent density were evident overall and within menopausal status categories. The minimum difference in percent density between the tallest and shortest girls was 3 percent, with a maximum of 7 percent. Weight at age 12 years (p 0.005) and adiposity at age 12 years (p 0.005) were both inversely associated with adult percent density. Adolescent physical activity and diet were unrelated to percent density. These results suggest that adolescent height, a known risk factor for breast cancer, is also associated with mammographic percent density. adiposity; anthropometry; breast; breast neoplasms; diet; exercise; mammograph