Campus Only Senior Thesis
Bachelor of Arts
W.M. Keck Science Department
Holly R. Harris
© Sable Fest
High levels of circulating sex steroid hormones have been associated with higher breast cancer risk. Some dietary factors have been hypothesized to play a role in the development of breast cancer; however, few studies have considered the influence of diet on premenopausal sex steroid hormone levels. Using reduced rank regression among a subset of participants from the Nurses’ Health Study II (NHSII), we identified dietary patterns correlated with premenopausal levels of twelve sex steroid hormones. Each pattern was then applied to the full NHSII cohort to investigate the association between premenopausal sex steroid hormone-related dietary patterns and breast cancer risk. Two exposure windows for dietary intake were examined: early adulthood intake and cumulative average adult intake. Individual dietary patterns were found to be moderately correlated with each hormone of interest but explained low percent variations (ranging from 0.02 to 0.11) in individual hormone levels. From 1991-2015, 3,891 incident cases of breast cancer were ascertained. Follicular estrone-related dietary patterns were significantly positively associated with overall breast cancer risk for cumulative average adult diet (HR comparing the 5th to 1st quintile=1.12; 95% CI=1.01-1.24; Ptrend=0.03). When examining early adulthood diet, follicular estradiol (HR=1.13; 95% CI=1.02-1.25; Ptrend=0.02), DHEA (HR=1.12; 95% CI=1.01-1.24; Ptrend=0.03), and prolactin (HR=1.15; 95% CI=1.04-1.27; Ptrend=0.03) associated patterns were found to be significantly positively associated with overall breast cancer risk. Overall, our findings suggest that while some dietary factors may marginally influence sex steroid hormone levels, the impact of sex steroid hormones on breast cancer risk is not driven by dietary factors.
Fest, Sable, "Premenopausal Hormone-associated Dietary Patterns and Breast Cancer Risk" (2022). Scripps Senior Theses. 2000.
Available for download on Monday, December 11, 2023
This thesis is restricted to the Claremont Colleges current faculty, students, and staff.