Purpose: Alcohol intake may be associated with cancer risk, but epidemiologic evidence for prostate cancer is inconsistent. We aimed to prospectively investigate the association between midlife alcohol intake and drinking patterns with future prostate cancer risk and mortality in a population-based cohort of Finnish twins.
Methods: Data were drawn from the Older Finnish Twin Cohort and included 11,372 twins followed from 1981 to 2012. Alcohol consumption was assessed by questionnaires administered at two time points over follow-up. Over the study period, 601 incident cases of prostate cancer and 110 deaths from prostate cancer occurred. Cox regression was used to evaluate associations between weekly alcohol intake and binge drinking patterns with prostate cancer risk and prostate cancer-specific mortality. Within-pair co-twin analyses were performed to control for potential confounding by shared genetic and early environmental factors.
Results: Compared to light drinkers (≤3 drinks/week; non-abstainers), heavy drinkers (>14 drinks/week) were at a 1.46-fold higher risk (HR 1.46; 95 % CI 1.12, 1.91) of prostate cancer, adjusting for important confounders. Among current drinkers, binge drinkers were at a significantly increased risk of prostate cancer (HR 1.28; 95 % CI 1.06, 1.55) compared to non-binge drinkers. Abstainers were at a 1.90-fold higher risk (HR 1.90; 95 % CI 1.04, 3.47) of prostate cancer-specific mortality compared to light drinkers, but no other significant associations for mortality were found. Co-twin analyses suggested that alcohol consumption may be associated with prostate cancer risk independent of early environmental and genetic factors.
Conclusion: Heavy regular alcohol consumption and binge drinking patterns may be associated with increased prostate cancer risk, while abstinence may be associated with increased risk of prostate cancer-specific mortality compared to light alcohol consumption.
Keywords: Alcohol; Binge drinking; Prospective cohort study; Prostate cancer; Twins.