Abstract 4346: Adolescent fiber intake and mammographic breast density in premenopausal women

Proceedings: AACR 107th Annual Meeting 2016; April 16-20, 2016; New Orleans, LA Background: Some, but not all, previous studies have suggested that higher adolescent fiber intake may be associated with a reduced risk of breast cancer. Consistently, adolescent fiber intake has been suggested to reduce breast cancer risk in adulthood in some of the previous studies. To date, there is limited epidemiologic evidence that diet has a strong influence on mammographic density and inconsistency in results for specific dietary factors. While some earlier studies demonstrated an inverse association between adolescent fiber intake and breast density (defined as parenchymal patterns), a more recent study did not find significant associations. We investigated the associations of adolescent fiber intake with mammographic density, a strong and consistent predictor of breast cancer, in premenopausal women. This is by far the largest study that investigated these associations. Methods: This study included 743 premenopausal women within the Nurses’ Health II cohort with no history of breast or other cancer. Percent breast density, absolute dense and non-dense areas were measured from digitized film mammographic images using a computer-assisted thresholding technique. Adolescent and adult diet was assessed with a food frequency questionnaire and energy-adjusted nutrient intakes were estimated for each of the questionnaires. Information regarding breast cancer risk factors was obtained from baseline or biennial questionnaires, closest to the mammogram date. We used generalized linear regression to quantify associations between quartiles of adolescent fiber intake and each of the breast density measures, adjusting for age, body mass index, and other known and suspected predictors of mammographic density. Absolute measures were square root-transformed in analyses to improve normality. Associations were examined separately for total fiber intake; fiber from fruits, vegetables, legumes, and cereal; and food sources of fiber (fruits, vegetables, and nuts). Results: In multivariable analyses, total fiber intake during adolescence was not associated with percent breast density (p for trend = 0.64), absolute dense area (p for trend = 0.80), or non-dense area (p for trend = 0.75). Similarly, neither consumption of nuts, fruits, or vegetables nor specific sources of fiber intake (fruits, vegetables, legumes, or cereal) during adolescence were associated with any of the mammographic density phenotypes. Conclusions: Our findings do not support the hypothesis that adolescent fiber intake is associated with premenopausal mammographic density. If observed associations with breast cancer risk are causal, then the effect may not be mediated through mammographic density. Citation Format: Lusine Yaghjyan, Gabriella Ghita, Maryam Farvid, Bernard Rosner, Kimberly A. Bertrand, Rulla Tamimi. Adolescent fiber intake and mammographic breast density in premenopausal women. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4346.