Body size from birth through adolescence in relation to risk of benign breast disease in young women

Body size, from birth throughout adulthood, is associated with breast cancer risk, but few studies have investigated early-life body size and benign breast disease (BBD), a well-established breast cancer risk factor. We consider whether prenatal factors and size at birth, 10, 18 year, and intervening growth, are related to BBD risk.

Girls had greater adiposity (BMI; kg/m²) at 10 year if they were larger at birth, if mother’s pre-pregnancy BMI was higher, or if gestational weight gain was greater (all p < .01). Maternal height was (positively) associated (p < .05) with adolescent peak height growth velocity (PHV; in./year). Greater 10 year adiposity was associated with lower PHV and less height growth 10–18 year (both p < .01). Adiposity at 10 year was inversely associated with BBD (OR 0.83/(kg/m²), p < .01) as was increasing adiposity 10–18 year (OR 0.85/(kg/m²), p = .01). In a separate model, 10 year height (OR 1.13/in., p = .02) and height growth 10–18 year (OR 1.19/in.; p < .01) were positively associated. PHV was similarly positively associated (OR 2.58, p = .01, fastest versus slowest growth quartiles). In a multivariable model of BBD risk, gestational weight gain (daughters at highest risk if <20 lb gained), PHV (slowest growing girls at lowest risk), age 10 year height (positive), and BMI (inverse) were the most critical childhood risk factors (each p < .05).

Body size factors from pregnancy through adolescence were independently associated with BBD risk in young women.