Binge drinking modifies the association between lifetime alcohol intake and breast cancer risk in moderate drinkers
Menée aux Etats-Unis à partir de données portant sur 50 884 femmes âgées entre 35 et 74 ans, cette étude évalue l'effet d'une pratique épisodique d'alcoolisation excessive sur l'association entre une consommation d'alcool mesurée tout au long de la vie et le risque de développer un cancer du sein (durée moyenne de suivi : 6,4 ans ; 1 843 cas)
The prevalence of binge drinking is rising in the United States. While alcohol is a breast cancer risk factor, less is known about the impact of episodic heavy drinking. Breast cancer-free women, ages 35–74, were enrolled in the Sister Study from 2003–2009 (n = 50,884). United States or Puerto Rico residents who had a sister with breast cancer were eligible. Multivariable Cox regression was used to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for breast cancer. 1,843 invasive breast cancers were diagnosed during follow-up (mean = 6.4 years). Increased breast cancer risk was observed for higher lifetime alcohol intake (≥230 drinks/year, HR = 1.35, 95% CI: 1.15, 1.58 versus <60 drinks/year). Relative to low drinkers, HRs were increased for ever binge drinking (HR = 1.29, 95% CI: 1.15, 1.45) or blacking out (HR = 1.39, 95% CI: 1.17, 1.64). Compared to low drinkers who never binged, moderate drinkers who binged had a higher risk (HR = 1.25, 95% CI: 1.08, 1.44). There was evidence of effect modification between moderate lifetime drinking and binging (relative excess risk due to interaction (RERI) = 0.33, 95% CI: 0.10, 0.57). Our findings support the established association between lifetime alcohol and breast cancer and provide evidence for an increased risk associated with heavy episodic drinking, especially among moderate lifetime drinkers.