Adiposity during early adulthood, changes in adiposity during adulthood, attained adiposity, and mammographic density among premenopausal women.

PURPOSE: We investigated the associations of adolescent adiposity, changes in adiposity during adulthood, and attained adiposity with volumetric mammographic density measures. METHODS: We recruited 383 premenopausal women who had a routine screening mammogram at the Breast Health Center, Washington University in St. Louis, MO from December 2015 to October 2016. Trained research personnel assessed current adiposity measures. Weight at ages 18 and 30 were self-reported. We evaluated mammographic density measures: volumetric percent density (VPD), dense volume (DV), and non-dense volume (NDV) using Volpara. Multivariable linear regression models were used to evaluate the associations of adiposity measures with volumetric mammographic density measures. RESULTS: All attained adiposity measures, BMI at age 18, age 30, and weight change were significantly inversely associated with VPD, and positively associated with DV and NDV. One unit increase in body fat % was associated with a 4.9% decrease in VPD and a 6.5% increase in NDV (p-values <0.001). For each kilogram increase in weight change from age 18 to attained, VPD decreased by 16.3%, 47.1%, and 58.8% for women who gained 5.1-15, 15.1-25 and >25 kg, respectively, compared to women who gained less than 5 kg during this time period (p-values <0.001). Irrespective of BMI at age 18, VPD significantly decreased and NDV increased among women who were currently obese. CONCLUSIONS: There is a need for mechanistic studies focusing on early adulthood to provide a better understanding of how adiposity in early life relates to mammographic density, and possibly breast cancer development in premenopausal women.