Dairy intakes in older girls and risk of benign breast disease in young women.

Previous investigations found high dairy intakes in girls associated with rapid height growth and excess weight gain, which had opposite relationships with benign breast disease (BBD) in young women. We use data from the longitudinal Growing Up Today Study (GUTS) to investigate whether dairy intakes, in older children/adolescents, are associated with BBD risk in young women. GUTS includes 9,039 females, ages 9-15 years in 1996, who completed questionnaires annually through 2001, then in 2003, 2005, 2007, and 2010. Dietary food frequencies (1996-2001) obtained milk, yogurt, and cheese intakes. On 2005-2010 surveys, 7,011 females (18-29 years) reported whether a health care provider ever diagnosed them with BBD (n = 250) and if confirmed by breast biopsy (n = 105). Logistic regression models estimated associations between prevalent biopsy-confirmed BBD and dairy intakes, adjusted for age and energy. Multivariable-adjusted models additionally included menarche age, childhood adiposity, adolescent alcohol consumption, and pregnancy. Further analyses stratified by family history. Age-energy-adjusted models of dairy (milk, yogurt, cheese, total dairy servings, dairy protein, dairy fat) intakes at 14 yr found no significant associations with BBD risk [milk: OR, 0.90/(serving/d); 95% confidence interval (CI), 0.76-1.05; dairy protein: OR, 0.98/(10 g/d); 95% CI, 0.82-1.17). Separate analyses of dairy intakes at 10 yr, intakes before the growth spurt, during the growth spurt, before menses-onset, and after menses-onset provided no significant associations with BBD. Multivariable adjustment, and family history stratification, did not alter the above findings. We conclude that dairy intakes by older girls have no strong relation with BBD risk in young women. Because of small number of cases, it is important to continue follow-up and re-examine later.