Alcohol: Drinking Alcohol Increases Risk of Breast Cancer
Weight and Body Composition: Excess body fat increases risk for post-menopausal breast cancer. Lean muscle, low body fat decreases risk of pre-menopausal breast cancers
Physical Activity: Sedentary behaviour is linked to increased risk of breast cancer, while being active decreases the risk of breast cancer.
Vigorous activity decreases the risk for pre-menopausal breast cancer.
Moderate activity decreases risk for post-menopausal breast cancer.
Some evidence indicates that people who are physically active (both before and after diagnosis) have a greater chance of surviving breast cancer.
Breastfeeding: Reduces risk of both pre- and post-menopausal breast cancer.
Sleep: Women who report sleeping less than 5 hours per night before diagnosis have an increased risk of dying from breast cancer compared to women whose pre-diagnosis sleep pattern was 7-8 hours per night. Women who have disrupted circadian rhythms due to night shift work have an increased risk of breast cancer.
References:
Diet, Nutrition, Physical Activity and Breast Cancer, Report from American Institute for Cancer Research. https://www.aicr.org/wp-content/uploads/2020/01/breast-cancer-report-2017.pdf
Allison Soucise et al Sleep quality, duration, and breast cancer aggressiveness
Breast Cancer Res Treat. 2017Jul;164(1):169-178. doi: 10.1007/s10549-017-4245-1. Epub2017 Apr17.
Vogtmann E, et al Association between sleep and breast cancer incidence among postmenopausal women in the Women's Health Initiative.
Sleep. 2013 Oct 1;36(10):1437-44. doi: 10.5665/sleep.3032.