BACKGROUND: Alcohol consumption and cigarette smoking are associated with an increased risk of breast cancer (BC), but it is unclear whether these associations vary by a woman's familial BC risk.
METHODS: Using the Prospective Family Study Cohort, we evaluated associations between alcohol consumption, cigarette smoking, and BC risk. We used multivariable Cox proportional hazard models to estimate hazard ratios (HR) and 95% confidence intervals (CI). We examined whether associations were modified by familial risk profile (FRP), defined as the 1-year incidence of BC predicted by Breast Ovarian Analysis of Disease Incidence and Carrier Estimation Algorithm (BOADICEA), a pedigree-based algorithm.
RESULTS: We observed 1009 incident BC cases in 17,435 women during a median follow-up of 10.4 years. We found no overall association of smoking or alcohol consumption with BC risk (current smokers compared with never smokers HR 1.02, 95% CI 0.85-1.23; consuming >/= 7 drinks/week compared with non-regular drinkers HR 1.10, 95% CI 0.92-1.32), but we did observe differences in associations based on FRP and by estrogen receptor (ER) status. Women with lower FRP had an increased risk of ER-positive BC associated with consuming >/= 7 drinks/week (compared to non-regular drinkers), whereas there was no association for women with higher FRP. For example, women at the 10th percentile of FRP (5-year BOADICEA = 0.15%) had an estimated HR of 1.46 (95% CI 1.07-1.99), whereas there was no association for women at the 90th percentile (5-year BOADICEA = 4.2%) (HR 1.07, 95% CI 0.80-1.44). While the associations with smoking were not modified by FRP, we observed a positive multiplicative interaction by FRP (pinteraction = 0.01) for smoking status in women who also consumed alcohol, but not in women who were non-regular drinkers.
CONCLUSIONS: Moderate alcohol intake was associated with increased BC risk, particularly for women with ER-positive BC, but only for those at lower predicted familial BC risk (5-year BOADICEA < 1.25). For women with a high FRP (5-year BOADICEA >/= 6.5%) who also consumed alcohol, being a current smoker was associated with increased BC risk.
Nonalcoholic fatty liver disease (NAFLD) comprises more than two thirds of patients with chronic liver disease in the United States. The effect of alcohol consumption on survival in patients with NAFLD is not clear. We gathered data on National Health and Nutrition Examination Survey participants from 1988 to 2010, and linked them to the National Death Index for follow-up of their survival. We diagnosed NAFLD based on a previously validated biochemical model (Hepatic Steatosis Index). We built multivariate Cox proportional hazards models to evaluate the effect of alcohol consumption on survival of patients with NAFLD. After excluding participants with significant alcohol use, viral hepatitis, or increased transferrin saturation, 4,568 participants with NAFLD were included in the analysis. In a Cox model adjusted for age, sex, and smoking history, drinking 0.5-1.5 drinks per day decreased the risk of overall mortality by 41% (hazard ratio [HR] = 0.59, 95% confidence interval [CI] 0.40-0.85, P = 0.005) compared with not drinking. Drinking >/=1.5 drinks per day showed a trend toward harm (HR = 1.16, 95% CI 0.99-1.36, P = 0.119). After further adjustment for race, physical activity, education level, diabetes, and fiber and polyunsaturated fatty acid intake, drinking 0.5-1.5 drinks per day continued to show a significant protective effect (HR = 0.64, 95% CI 0.42-0.97, P = 0.035), and drinking >/=1.5 drinks per day showed a significant harmful effect on mortality (HR = 1.45, 95% CI 1.01-2.10, P = 0.047). Among patients with NAFLD, modest alcohol consumption is associated with a significant decrease in all-cause mortality, whereas drinking >/=1.5 drinks per day is associated with an increase in mortality. These results help to inform the discussion of potential risks and benefits of alcohol use in patients with NAFLD.