Light to Moderate Alcohol Consumption and Cancer Incidence: The Norwegian Women and Health Cohort Study

Abstract

Purpose: To investigate the impact of light-moderate (up to 20 g/day) alcohol consumption on incidence of postmenopausal breast, kidney, lung, pancreatic, colorectal, postmenopausal ovarian and postmenopausal endometrial cancer among women. Methods: Participants were 70,932 women aged 41–70 years, randomly recruited in the Norwegian Women and Health (NOWAC) cohort study from 1996 to 2004. We included women who reported that they consumed alcohol. Only postmenopausal women (N = 32,735) were included in the analyses for female cancers. Multivariable Cox proportional hazard models were used to estimate hazard ratios (HR) and 95% confidence intervals (CI). Results: The mean follow-up was 19 years. The estimated hazard ratio (HR) from each additional 12g/day of alcohol consumption for postmenopausal breast cancer was 1.20 (95% confidence intervals CI: 1.03 to 1.41), and for kidney cancer 0.42 (95% CI: 0.24 to 0.75). The corresponding estimates for postmenopausal breast cancer among women who used menopausal hormone therapy (MHT) were HR = 1.27, 95% CI: 1.05 to 1.54, and among women who never used MHT were HR = 1.12, 95% CI: 0.86 to 1.47. Compared to alcohol consumption of <3.5 g/day, consumption of 3.5–10 g/day revealed for lung cancer inverse association with risk of lung cancer among women who consumed primarily wine (HR = 0.65, 95% CI; 0.43 to 0.88), but not among other drinkers (HR = 1.10, 95% CI; 0.88 to 1.31). No associations were confined for pancreatic, colorectal, ovarian and endometrial cancers. Conclusion: Women drinking light-moderate alcohol level had a higher risk of postmenopausal breast cancer and a lower risk of kidney cancer incidence. Our results do not support the threshold of up to 1 drink/day as a safe limit for breast cancer, especially for postmenopausal women who use MHT. The inverse relationship found for lung cancer could be explained by the healthier lifestyle correlated with this light-moderate drinking.