Lifetime dairy product consumption and breast cancer risk: a prospective cohort study by tumor subtypes

Emily Riseberg; You Wu; Wai Ching Lam; A Heather Eliassen; Molin Wang; Xuehong Zhang; Walter C Willett; Stephanie A Smith-Warner

doi:10.1016/j.ajcnut.2023.11.017

Lifetime dairy product consumption and breast cancer risk: a prospective cohort study by tumor subtypes

Am J Clin Nutr. 2024 Feb;119(2):302-313. doi: 10.1016/j.ajcnut.2023.11.017. Epub 2023 Nov 30.

Authors

Emily Riseberg¹, You Wu², Wai Ching Lam³, A Heather Eliassen⁴, Molin Wang⁵, Xuehong Zhang⁶, Walter C Willett⁷, Stephanie A Smith-Warner⁷

Affiliations

¹ Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, United States.
² Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, United States; Institute for Hospital Management, School of Medicine, Tsinghua University, Beijing, China; Department of Health Policy and Management, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, United States. Electronic address: youwu@tsinghua.edu.cn.
³ Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, United States; Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, United States.
⁴ Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, United States; Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, United States; Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, United States.
⁵ Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, United States; Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, MA, United States; Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, United States.
⁶ Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, United States; Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, United States.
⁷ Department of Nutrition, Harvard T.H. Chan School of Public Health, Boston, MA, United States; Department of Epidemiology, Harvard T.H. Chan School of Public Health, Boston, MA, United States.

PMID: 38042408
PMCID: PMC10884601 (available on 2024-11-30)
DOI: 10.1016/j.ajcnut.2023.11.017

Abstract

Background: Previous literature on dairy products and risk of breast cancer is inconsistent, and the relationship may depend on the life-period of dietary assessment.

Objective: We examined dairy consumption from adolescence through later adulthood and incidence of breast cancer by menopausal status and tumor molecular subtypes in the Nurses' Health Study (NHS), a prospective cohort study.

Methods: We analyzed data from 63,847 females in the NHS collected from 1980 to 2018. Average intake of dairy products during adulthood was assessed by validated semiquantitative food frequency questionnaires throughout follow-up. Participants recalled adolescent dietary intake in 1986. Multivariable Cox proportional hazards models were used to estimate hazard ratios (HRs) relating dairy product consumption to breast cancer risk overall, by menopausal status, and by subtypes.

Results: We documented 5733 incident cases of invasive breast cancer during 32 y of follow-up (n = 5298 postmenopausal). Lifetime, adolescent, adulthood, and postmenopausal total dairy and milk intakes were not associated with overall breast cancer risk (nonsignificant HRs comparing highest with lowest quintile range = 0.97-1.08), although there was a suggestive positive association between adolescent milk intake and breast cancer risk (HR: 1.09; 95% CI: 1.00, 1.18). Higher lifetime and premenopausal cheese intakes were associated with modestly lower risks of breast cancer (comparing highest with lowest quintile, HR for lifetime cheese intake: 0.90; 95% CI: 0.82, 0.98; HR for premenopausal cheese intake: 0.89; 95% CI: 0.79, 1.00). Results varied by tumor subtype and some evidence for heterogeneity was observed for an association between premenopausal milk intake and breast cancer (HR for estrogen receptor [ER]-positive: 0.84; 95% CI: 0.72, 0.99; ER-negative: 1.36; 95% CI: 1.00, 1.84; P heterogeneity = 0.04).

Conclusions: These findings suggest that overall dairy consumption was not associated with risk of breast cancer. However, heterogeneity was observed for type of dairy food, period of life, and tumor subtypes.

Keywords: Nurses’ Health Study; adolescent diet; breast cancer; cheese; dairy; life course; milk.

MeSH terms

Adolescent
Adult
Breast Neoplasms* / epidemiology
Breast Neoplasms* / etiology
Dairy Products
Diet
Female
Humans
Incidence
Prospective Studies
Risk
Risk Factors