Alcohol consumption and breast cancer risk in Japan: A pooled analysis of eight population‐based cohort studies

Abstract

Although alcohol consumption is reported to increase the incidence of breast cancer in European studies, evidence for an association between alcohol and breast cancer in Asian populations is insufficient. We conducted a pooled analysis of eight large‐scale population‐based prospective cohort studies in Japan to evaluate the association between alcohol (both frequency and amount) and breast cancer risk with categorization by menopausal status at baseline and at diagnosis. Estimated hazard ratios (HR) and 95% confidence intervals were calculated in the individual cohorts and combined using random‐effects models. Among 158 164 subjects with 2 369 252 person‐years of follow‐up, 2208 breast cancer cases were newly diagnosed. Alcohol consumption had a significant association with a higher risk of breast cancer in both women who were premenopausal at baseline (regular drinker compared to nondrinker: HR 1.37, 1.04‐1.81, ≥23 g/d compared to 0 g/d: HR 1.74, 1.25‐2.43, P for trend per frequency category: P = .017) and those who were premenopausal at diagnosis (≥23 g/d compared to 0 g/d: HR 1.89, 1.04‐3.43, P for trend per frequency category: P = .032). In contrast, no significant association was seen in women who were postmenopausal at baseline or at diagnosis, despite a substantial number of subjects and long follow‐up period. Our results revealed that frequent and high alcohol consumption are both risk factors for Asian premenopausal breast cancer, similarly to previous studies in Western countries. The lack of a clear association in postmenopausal women in our study warrants larger investigation in Asia.

Comprehensive profiles and diagnostic value of menopausal-specific gut microbiota in premenopausal breast cancer

“…A meta-analysis of a prospective study showed that total fiber (especially soluble fiber) consumption was associated with an 8% lower risk of breast cancer 57 . Moreover, in a study of an Asian population, regular consumption of Lactobacillus casei Shirota (BLS), soy isoflavone, and vitamin D reduced breast cancer risk in premenopausal women, whereas alcohol consumption was significantly associated with a higher risk of breast cancer, specifically in premenopausal women 58 – 60 .…”

A Personal Breast Cancer Risk Stratification Model Using Common Variants and Environmental Risk Factors in Japanese Females

“…When aggregated, however, these risk alleles together would likely indicate substantial risk elevation in those in the high-risk group. In previous studies in Japanese females, the impact of genetic risk in the high-risk groups was larger than that of cigarette smoking, alcohol drinking and obesity [47][48][49][50]. Unlike smoking, drinking and obesity, however, genetic risk cannot be modified.…”

Early Alcohol Use Initiation, Obesity, Not Breastfeeding, and Residence in a Rural Area as Risk Factors for Breast Cancer: A Case-Control Study

“…Other studies have also shown a positive relationship between alcohol consumption and an increased risk of breast cancer [31][32][33][34]. A Japanese study that shed more light on the effects of alcohol consumption on breast cancer found that the risk was greater only in premenopausal women [35]. Unfortunately, despite the fact that many studies on alcohol consumption among adult women have been conducted in the context of breast cancer, little research has focused on the effects of alcohol consumption in childhood and adolescence.…”