Fruit and vegetable consumption and breast cancer incidence: Repeated measures over 30 years of follow‐up

• Published in: International journal of cancer Vol. 144; no. 7; pp. 1496 - 1510
• Main Authors: Farvid, Maryam S., Chen, Wendy Y., Rosner, Bernard A., Tamimi, Rulla M., Willett, Walter C., Eliassen, A. Heather
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.04.2019; Wiley Subscription Services, Inc
• Subjects: Adult; Breast cancer; Breast Neoplasms - epidemiology; Breast Neoplasms - metabolism; Cancer; Epidermal growth factor; ErbB-2 protein; estrogen receptor; Female; Follow-Up Studies; Fruit; fruit and vegetable; Fruits; Health risk assessment; Humans; Incidence; Invasiveness; Medical research; Middle Aged; molecular subtype; Nutrition Assessment; Nutrition Surveys; Prospective Studies; Receptor, ErbB-2 - metabolism; Risk factors; Tumors; Vegetables; Within-subjects design; breast cancer; estrogen receptor; fruit and vegetable; molecular subtype
• ISSN: 0020-7136; 1097-0215; 1097-0215
• DOI: 10.1002/ijc.31653

We evaluated the relation of fruit and vegetable consumption, including specific fruits and vegetables, with incident breast cancer characterized by menopausal status, hormone receptor status and molecular subtypes. Fruit and vegetable consumption, cumulatively averaged across repeated, validated questionnaires, was examined in relation to risk of invasive breast cancer among 182,145 women initially aged 27–59 years in the Nurses’ Health Study (NHS, 1980–2012) and NHSII (1991–2013). Cox proportional hazards regression, adjusted for known risk factors, was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) and assessed tumors by hormone receptor status and molecular subtypes. We prospectively documented 10,911 invasive breast cancer cases. Greater intake of total fruits and vegetables, especially cruciferous and yellow/orange vegetables, was associated with significantly lower breast cancer risk (>5.5 vs. ≤2.5 servings/day HR = 0.89, 95% CI = 0.83–0.96; ptrend = 0.006). Intake of total vegetables was especially associated with lower risk of estrogen receptor negative tumors (HR per 2 additional servings/day as a continuous variable = 0.84, 95%CI = 0.77–0.93; pheterogeneity = 0.02). Among molecular subtypes, higher intake of total fruits and vegetables (HR per 2 additional servings/day as a continuous variable) was most strongly associated with lower risk of human epidermal growth factor receptor 2 (HER2)‐enriched (HR = 0.79, 95%CI = 0.67–0.93), basal‐like (HR = 0.84, 95%CI = 0.72–0.97) and luminal A (HR = 0.94, 95%CI = 0.89–0.99), but not with luminal B tumors (pheterogeneity = 0.03). In conclusion, our findings support that higher intake of fruits and vegetables, and specifically cruciferous and yellow/orange vegetables, may reduce the risk of breast cancer, especially those that are more likely to be aggressive tumors. What's new? Fruits and vegetables are rich in potentially anti‐carcinogenic nutrients including fiber, vitamins C and E, carotenoids, and other bioactive substances. However, many studies found no association between fruit and vegetable consumption and risk of breast cancer. In this analysis based on two large prospective cohorts, the authors found that higher total fruit and vegetable consumption during adulthood was associated with a modest, statistically significant lower invasive breast cancer incidence, with the strongest associations for ER‐negative, HER2‐enriched and basal‐like tumors. Higher intake of fruits and vegetables, and specifically cruciferous and yellow/orange vegetables, may reduce the risk of breast cancer, especially aggressive tumors.