Alcohol Use and Breast Cancer: A Critical Review

Abstract

The objective of this study was to outline the biological pathways of alcohol-attributable breast cancer, the epidemiological risk relationship between alcohol consumption and breast cancer, and the global burden of breast cancer incidence and mortality attributable to alcohol consumption, with a focus on light drinking. First, the literature regarding the biological mechanisms of how alcohol affects the risk of breast cancer was reviewed and summarized. Second, a search of meta-analyses that evaluated the risk relationship between alcohol consumption and breast cancer was conducted. Last, the burden of alcohol-attributable breast cancer incidence and mortality was estimated by means of a Population-Attributable Fraction methodology. Data on alcohol consumption were obtained from the Global Information System on Alcohol and Health, and data on cancer incidence and mortality were obtained from the GLOBOCAN database. Alcohol consumption affects breast cancer risk through the alteration in hormone levels and the associated biological pathways, the metabolism of ethanol resulting in carcinogens, and the inhibition of the one carbon metabolism pathway. The systematic review found 15 meta-analyses on the risk relationship between alcohol consumption (also light consumption) and the risk of breast cancer. All but 2 of these analyses showed a dose-response relationship between alcohol consumption and the risk of breast cancer. An estimated 144,000 (95% confidence interval [CI]: 88,000 to 200,000) breast cancer cases and 38,000 (95% CI: 2,400 to 53,000) breast cancer deaths globally in 2012 were attributable to alcohol, with 18.8% of these cases and 17.5% of these deaths affecting women who were light alcohol consumers. All levels of evidence showed a risk relationship between alcohol consumption and the risk of breast cancer, even at low levels of consumption. Due to this strong relationship, and to the amount of alcohol consumed globally, the incidence of and mortality from alcohol-attributable breast cancer is large.

The relationship between different dimensions of alcohol use and the burden of disease—an update

“…There are at least four other pathways by which alcohol use may increase the risk of cancer. First, alcohol may alter the one carbon metabolism by inhibiting folate absorption, leading to increased homocysteine concentrations 150, 151, and by inhibiting folate cycle enzyme methionine synthase and the trans‐methylation enzymes methionine adenosyltransferase and DNA methyltransferase 150, 152. Secondly, alcohol may affect serum levels of hormones and related signalling pathways, leading to an increased risk of breast cancer, and possibly of prostate, ovarian and endometrial cancers 153, 154, 155.…”

A narrative review of alcohol consumption as a risk factor for global burden of disease

“…Take breast cancer as an example: there have been more than 100 single studies and 16 systematic reviews with meta-analyses over the past 20 years [85]. However, the main conclusions on relative risk did not change: there is a clear dose-response relationship with no protective effect for any level of drinking compared to lifetime abstainers [85]. Even drinking as low as one drink on average is associated with increased risk for breast cancer [85, 86].…”

“…However, the main conclusions on relative risk did not change: there is a clear dose-response relationship with no protective effect for any level of drinking compared to lifetime abstainers [85]. Even drinking as low as one drink on average is associated with increased risk for breast cancer [85, 86]. The quantification for the different levels of alcohol-attributable risk for breast cancer had been quite similar over the years [85], as they had been for cancer in general (e.g., [87], which has been used to date for the CRAs, and [47]; which will be used in the future).…”

Prospective study of the dietary inflammatory index and risk of breast cancer in postmenopausal women

“…There is strong evidence suggesting reproductive and hormonal factors [3] and a few strongly penetrant genes (e.g., BRCA1 and BRCA2) [4], as risk factors for breast cancer. The role of diet and inflammation in the etiology of breast cancer is unclear [5, 6]; however, some evidence suggests an etiologic role for diet, in particular the ability of foods to modulate inflammation in the etiology of the disease [7] with alcohol consumption being consistently shown to increase risk of breast cancer [8]. …”