Coffee reduces the risk of postmenopausal breast cancer

reference

lafranconi a, Micek a, de Paoli P, et al. Coffee consumption reduces the risk of postmenopausal breast cancer: a dose-effect meta-analysis on prospective cohort studies. nutrients . 2018; 10 (2). PII: E112.

objective

Summary of knowledge from prospective cohort studies on the connection between coffee consumption and breast cancer risk.

draft

A dose-effect meta-analysis of prospective studies that evaluated relationships between doses of coffee consumption (including decaffeinated) and breast cancer risk. All studies contained data on the dose-effect relationship, the highest vs. lowest consumption or subgroup analyzes.

target parameter

Coffee consumption was calculated against the relative risk (RR) of a primary breast cancer diagnosis of 0 to 7 cups of coffee per day for the categories BMI, hormone receptor status and menopause status.

important knowledge

The dose-effect analysis of 13 prospective studies (overall over 1 million participants) showed no significant connection between coffee consumption and breast cancer risk in the non-linear model. However, a reverse relationship was observed when the analysis was limited to postmenopausal women. The consumption of 4 cups of coffee per day was associated with a 10 % reduction in postmenopausal cancer risk (RR: 0.90; 95 % confidence interval [CI]: 0.82–0.99). Subgroup analyzes showed consistent results for all examined potential disruptive factors. These results support the hypothesis that coffee consumption is associated with a reduced risk of postmenopausal breast cancer. The association of a reduced risk in postmenopausal women was regardless of whether the coffee was caffeine or decaffeinated.

practice implications

The relationship between coffee and breast cancer was difficult to determine. In recent years, coffee has been seen as potentially advantageous for human health. A literature search in August 2017 indicated that coffee could be associated with a reduced risk for a number of diseases, including cardiovascular diseases and cardiovascular mortality, Parkinson's disease, type 2 diabetes and breast, intelligence and prostate cancer.

prospective cohort observation studies indicate that a moderate to high coffee consumption is associated with a lower risk of overall mortality, cardiovascular and cancer mortality compared to a lower consumption.

The association of a reduced risk in postmenopausal women was regardless of whether the coffee was caffeine or decaffeinated.

The hypothesis was set up that coffee consumption influences the risk of female cancer, including breast, uterine mucosa and ovarian cancer, especially in postmenopausal women. A recently carried out analysis of the Nurse 'Health Study II grouped a low coffee consumption in a nutritional pattern that also included a low absorption of green leaf vegetables and cross -flowered vegetables. ^{3 Earlier attempts to meet meta analysis of data that deals with coffee consumption and the risk of cancer have not been clear, no clear results, In particular, no final dose-effect assocations found. 16 cohort and 10 case control studies and found only a borderline connection between the highest and lowest coffee consumption. However, they found a significant reverse connection between coffee consumption and cancer risk in estrogen receptor-negative women and also BRCA1-positive women. 5 Their results suggest that the attention of coffee on certain subgroups of women should be pointed out. (An overview of the meta -analysis by Li et al. Appeared in an earlier edition of the Natural Medicine Journal. 6 )}

This current analysis by Lafranconi et al. Has done exactly that and focused on the effects of coffee especially on postmenopausal women. They analyzed results from 13 prospective studies for a study population of more than 1 million women. While they found no significant connection between coffee consumption and the entire breast cancer risk, which is an important finding in itself, they found a significant relationship in postmenopausal women, i.e. h. A decrease in the risk of breast cancer. The consumption of 4 cups of coffee per day was associated with a 10% reduction in postmenopausal cancer risk (RR: 0.90; 95% CI: 0.82-0.99).

In this study, it did not matter whether the woman drank caffeine or decaffeinated coffee. Therefore, no earnings can be attributed to the caffeine for protection against breast cancer; Other connections in coffee must be responsible for this. It could be the many antioxidants in coffee. It could be the effect of coffee on the liver function or on the metabolic syndrome. The exact role that plays coffee and the mechanisms through which he could change the risk of breast cancer in this subgroup is unclear. We are waiting for future studies that could educate all of this.

In the meantime, it is becoming increasingly clear that coffee cannot increase breast cancer risk and that protection against breast cancer can offer for certain subgroups. This data relate to the diagnosis of primary cancer and probably tell us little about the effects of coffee on the risk of relapse.

There is another basic error in this data, which no statistical manipulation cannot compensate for: the participants were not selected by accident, who would drink coffee and who would not. These “free -living people” decided themselves whether and how much coffee was drunk. It may well be that these self -selected groups split over a quality that has not yet been defined that falsifies the results. The obvious possibility is what we see is a difference in the liver function or digestive function. A percentage of people intentionally avoids coffee because it keeps them awake at night, probably a symptom for a slow detoxification capacity of the liver.

The possible counter argument in this study is that decaffeinated coffee also showed protective advantages or at least seemed in this data. Nevertheless, many of us will think in this direction and do not rush to encourage every postmenopausal woman to drink 4 cups of coffee a day. Nevertheless, I will not discourage the women who do this.