Light to moderate alcohol consumption and cancer incidence: the Norwegian Women and Health cohort study

A study examined the effect of light to moderate (up to 20 g/day) alcohol consumption on the incidence of postmenopausal breast, kidney, lung, pancreatic, colorectal, ovarian, and endometrial cancers among women.
Participants included 70,932 women aged 41-70 years, randomly selected from the Norwegian Women and Health (NOWAC) cohort study between 1996 and 2004. The study involved women who reported alcohol consumption. 32,735 postmenopausal women 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).
The average follow-up period was 19 years. The estimated hazard ratio (HR) for each additional 12g/day of alcohol consumption and postmenopausal breast cancer was 1.20 (95% confidence interval [CI]: 1.03 to 1.41), while for kidney cancer it was 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 was associated with an inverse relationship with lung cancer risk among women who mainly drank 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 significant associations were observed for pancreatic, colorectal, ovarian, or endometrial cancers.
Women consuming light to moderate amounts of alcohol had a higher risk of postmenopausal breast cancer and a lower risk of kidney cancer. The study results do not support the idea that up to 1 drink per day is a safe limit for breast cancer risk, particularly for postmenopausal women who use MHT. The inverse association observed for lung cancer could be attributed to the healthier lifestyle often linked with light to moderate drinking.
Source: Llaha, F., Licaj, I., Sharashova, E., et al. (2025). Light to moderate alcohol consumption and cancer incidence: the Norwegian Women and Health cohort study. Clinical Epidemiology,17: 807-82.