Coffee and tea consumption and the risk of invasive breast cancer in postmenopausal women

This article is part of our special edition October 2021. Download the full edition here.

reference

KH Zheng, K. Zhu, J. Wactawski-Wende et al. Caffeine recording from coffee and tea and incidence of invasive breast Cancer in postmenopausal women in the Women’s Health Initiative [Published Online Ahead of Print, 2021 Aug 21]. intj cancer . 2021; 10.1002/IJC.33771. DOI: 10.1002/IJC.33771

Study goal

to determine whether there is a connection between the caffeine intake of coffee or tea and the development of invasive breast cancer in postmenopausal women

draft

prospective observation study

participant

The Women’s Health Initiative (Whi) recruited almost 100,000 women from 1993 to 1998 to take part in their observation study. Of these, 79,871 racial and ethnically different women from 40 centers in the United States were included in the present study. They were postmenopausal when recruiting and between 50 and 79 years old. The researchers excluded women from the present analysis if they suffered from cancer in the history of the history or had cancer at the beginning of the study.

study parameters evaluated

In an annual survey, the study participants were asked questions about their consumption of coffin -containing and decaffeinated coffee and tea, whereby the participants either have no, 1 cup, 2 to 3 cups, 4 to 5 cups or 6 or more cups. The caffeine recording from other sources has not been included and is not part of this study. The original study was carried out with the annual survey over a period of 10 years; However, there were 2 additional 5 -year extension studies until September 2015. Data on age, breed, ethnicity, education, smoking status and intensity, alcohol consumption and freight, sleep duration, movement, calorie intake, hormone therapy raised prehistory, age, age at menopause, age at the first fully carried out birth, parity and family history of Breast cancer. In addition, a questionnaire was used for healthy eating and the body mass index (BMI) was calculated from the size and weight raised by the researchers.

primary result measurements

The incidence of invasive breast cancer with collected data, including hormone receptor status, Her2 receptor status (human epidermal growth factor receptor 2), stage, degree, size, tumor type, lymph node status and histology.

The researchers subject these results of a multivariable analysis using covariates in groups of demographic variables (age, breed, ethnicity and education), lifestyle variables (smoking, alcohol, calorie intake, movement, values ​​for healthy eating, BMI and sleeping duration) and reproduction variable (use of hormone therapy, menarche, menopause, age at the first birth, parity and breast cancer in the family history).

important knowledge

When the researchers took all variables into account, they did not find any significant relationships between the risk of invasive breast cancer and the consumption of different amounts of caffeine through coffee or tea consumption. The lack of association was maintained when data for receptor subtypes, degree, stage and histology were isolated.

In the subgroup analysis, participants had participants who drank 2 to 3 cups of coffee a day, an increased risk of hormone receptor-positive cancer; However, after taking multiple comparisons into account, this was no longer statistically significant.

There was a statistical significance in the heterogeneity of the tea consumption between the hormone receptor status (he positively vs. negative) and the histological subtype (Duktal vs. lobulary).

practice implications

The positive or negative relationships between coffee and tea consumption and the risk of cancer in general have been discussed for a long time. What we found out through numerous studies is that many variables need to be taken into account. In addition to caffeine, coffee and tea contain many secondary plant substances; Therefore, the previous studies should not be interpreted as a replacement for caffeine intake. In addition, there are changes that occur in the processing of the coffee berries and tea leaves - roast or fermentation, as well as the natural variations of secondary plant substances that can be found in various cultivation areas - and this contributes to the complexity of what is being studied.

The study currently checked tried to determine whether the absorption of caffeine from coffee or tea is connected to the appearance of breast cancer in postmenopausal women. The results imply that there is no difference in breast cancer incidence, regardless of the consumption of normal or caffeine -free coffee or tea. However, one of the restrictions on the study was the lack of inclusion of other caffeine sources such as energy drinks, soft drinks or chocolate. The lack of these factors destroys the meaningfulness of this study towards caffeine effects and rather indicates that it is a study of the connections between coffee or tea consumption and breast cancer incidence.

The positive or negative relationships between coffee and tea consumption and the risk of cancer in general have been discussed for a long time.

These results are similar to those of the Black Women’s Health Study, 1 The Swedish lifestyle and health study for women, 2 and other cohort studies. However, this is in contrast to the positive effects of regular coffee consumption on the occurrence of breast cancer, which were found in the Nurses' Health Study. In the NMJ edition of August 2021 there is an excellent overview by Jacob Schor, ND, Fabno, about the analysis of the latter study.

This study was more specific for the risk of primary diagnosis of invasive breast cancer in coffee or tea consumption, in contrast to the effects of this consumption after breast cancer diagnosis. A recently by Farvid et al. Analysis of the data of the Nurses' Health Study carried out showed that there was a statistically significant reduction in deaths from breast cancer when consuming more than 3 cups of coffee.

What do these studies mean for clinical practice? According to this study, there seems to be no reason to change coffee or tea consumption in primary prevention of invasive breast cancer. According to the diagnosis of invasive breast cancer, a coffee consumption of more than 3 cups per day can be added as a tasty means of the treatment protocol to lower the breast cancer -specific mortality in our patients, at least among the patients who are able to do so.

The possible reservation when changing coffee or tea consumption in primary prevention remains the recommendation of green tea with a high catechine content. In a meta -analysis published in 2020, Wang et al. It is clear that the incidence of breast cancer is reduced with long -term, high intake of green tea. ^{4 This can differ from the results of the Women’s Health Initiative Study due to the specific type of analyzed tea consumption.}