Alcohol intake and mammographic density in postmenopausal Norwegian women

Abstract

Mammographic density is a strong risk factor for breast cancer. While alcohol intake has been associated with increased breast cancer risk, the association between alcohol consumption and mammographic density is not clear. We assessed the association between alcohol consumption and mammographic density among women who participated in the Norwegian Breast Cancer Screening Program in 2004. Mammographic density was assessed on digitized mammograms from 2,251 postmenopausal women aged 50-69 years, using a computer assisted method. Current intake of beer, wine (red and white), and liquor was assessed using a validated food frequency questionnaire. Non-drinkers were defined as complete abstainers (i.e., those who reported no intake of any type of alcohol). We used multivariate linear regression models to estimate least square means of percent mammographic density by categories of alcohol intake with adjustment for potential confounders. We also checked for possible effect modification by stratifying the analyses by age, body mass index, and hormone therapy. The mean percent mammographic density was almost similar for drinkers 18.3% (95% CI: 17.6-18.9%) and non-drinkers 17.8% (95% CI: 16.1-19.4%) (P = 0.59). There was no indication that amount of alcohol consumed was associated with percent mammographic density, with a mean percent density among women with the highest intake (>90 g of alcohol per week) of 18.2% (95% CI: 16.9-19.0%), only slightly different from that of non-drinkers 18.3% (17.3-19.6%) (P for trend = 0.99). There was no association between any type of alcohol consumed and mammographic density.There was no effect modification by body mass index, age, or hormone therapy use. We found no evidence of an association between alcohol intake and percent mammographic density.

The Association between Alcohol Consumption and Breast Density: A Systematic Review and Meta-analysis

“…Group 1 contained 11 studies (17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27), with a total of 61,229 subjects (of which 87.6% came from one study; ref. 25), that used quantitative methods, either computer assisted or visual estimation, to measure PBD in mammograms and used the continuous measures of PBD generated by these methods in the analysis of the association with alcohol consumption.…”

“…There was also variability between studies in the questions used to assess alcohol intake, and in the units in which alcohol intake was measured. Several studies (19,24,26,(28)(29)(30)33) noted that alcohol consumption was low within the study population, which may have influenced the results, and there were six studies (20-23, 36, 40) with less than 300 participants. These uncontrolled sources of variation are reflected in the tests of heterogeneity that were statistically significant in all three groups of studies and remained significant in the sensitivity analyses.…”

“…Alcohol intake was expressed variously as g/day (17,24,25,27,29,34), no alcohol use versus alcohol use times/year (19), servings/week (20), drinks/week (21-23) g/week (26,30), drinks/month (28), and tertiles of intake (35).…”

Breast Cancer Susceptibility Variants and Mammographic Density Phenotypes in Norwegian Postmenopausal Women

“…The characteristics of the 2004 sample and its participants have been previously described (44,47,49,50). In short, we sent a standardized questionnaire on various breast cancer risk factors (i.e., menstrual and reproductive history, use of oral contraceptives and menopausal hormonal therapy, family history of breast cancer, current weight, and height), together with the NBCSP invitation for screening, to a random sample of 17,050 women living in the counties of Oslo, Akershus and Hordaland in 2004.…”

“…Parity and possibly early age at first full-term pregnancy are both associated with lower percent MD (37)(38)(39)(40)(41). BMI is strongly inversely associated with percent MD (42), and there is some evidence that physical activity (43) and possibly alcohol intake (44)(45)(46) are associated with MD phenotypes. We and others have previously suggested the role of possible gene-environmental interactions in explaining variation in the effects of lifestyle factors on MD.…”