The purpose of this meta-analysis was to try to get some clarity and to summarize the evidence, from prospective cohort studies regarding the association between coffee intake and breast cancer risk.
The design was established to assess associations between amounts of decaffeinated and caffeinated coffee (from 0 to 7 cups of coffee per day) and breast cancer risks, including categories of body mass index, hormone receptor status and menopause status.
The analysis included 13 prospective studies totaling over 1 million participants, and concluded in showing no significant association between coffee consumption and breast cancer risk. However, when the analysis was specific to postmenopausal women, there was an inverse relationship to the tune of consumption of 4 cups of coffee per day was associated with a 10% reduction in postmenopausal cancer risk, no matter body mass index or hormone receptor status, or caffeinated or decaffeinated coffee….
Conclusion: coffee consumption is associated with a decreased risk of postmenopausal breast cancer.
Commentary: The last few years of coffee research has shown multiple potential benefits, suggesting reducing cardiovascular disease and cardiovascular mortality, Parkinson’s disease, type 2 diabetes, and cancers including breast/colon/endometrium and prostate.1
Overall, observational prospective cohort studies suggest that moderate-to-high coffee intake is associated with lower risk of mortality from any cause, and cardiovascular, and cancer mortality compared to lower consumption.2
Prior meta-analysis has not shown any clear results with coffee consumption and female cancers.3 In a 2013 meta-analysis of 16 cohort and 10 case-control studies, there was only a borderline association when comparing highest vs lowest coffee consumption although they did find a significant inverse association between coffee consumption and cancer risk in estrogen receptor–negative women and in BRCA1-positive women.4
In the current study, since there was no difference between caffeinated or decaffeinated coffee, there must be other compounds in the coffee that are responsible. Women and practitioners should not reduce coffee intake based on concerns regarding breast cancer, and if anything, perhaps we should consider encouraging coffee drinking in postmenopausal women, (although 4 cups per day may have other problems such as anxiety, insomnia, agitation, palpitations, breast tenderness) and perhaps even more so if there are other breast cancer risk factors (first degree family history, obesity, excess alcohol).
Reference
Lafranconi A, Micek A, De Paoli P, et al. Coffee intake decreases risk of postmenopausal breast cancer: a dose-response meta-analysis on prospective cohort studies. Nutrients. 2018;10(2). pii:E112.
Other References
1. Grosso G, Godos J, Galvano F, Giovannucci EL. Coffee, caffeine and health outcomes: an umbrella review. Annu Rev Nutr. 2017;37:131-156.
2. Grosso G, Micek A, Godos J, et al. Coffee consumption and risk of all-cause, cardiovascular and cancer mortality in smokers and non-smokers: a dose-response meta-analysis. Eur J Epidemiol. 2016;31:1191-1205.
3. Malerba S, Turati F, Galeone C, et al. A meta-analysis of prospective studies of coffee consumption and mortality for all causes, cancers and cardiovascular diseases. Eur J Epidemiol. 2013;28(7):527-539.
4. Li XJ, Ren ZJ, Qin JW, et al. Coffee consumption and risk of breast cancer: an up-to-date meta-analysis. PLoS One. 2013;8(1):e52681.
