Alcohol consumption, drinking patterns and cancer incidence in an Australian cohort of 226,162 participants aged 45 years and over

Background: Although overall alcohol consumption is known to increase the risk of a number of cancers internationally, evidence for Australia and evidence regarding the pattern of drinking and cancer risk is limited. Methods: Adjusted hazard ratios (HR) and 95% confidence intervals (CI) for cancer risk in relation to overall alcohol consumption (drinks/week) and pattern of drinking were calculated using Cox proportional hazard regressions for 226,162 participants aged ≥45 years (2006–2009) in the 45 and Up Study, an Australian prospective cohort study. Incident primary cancer cases were ascertained by linkage to the New South Wales Cancer Registry to 2013 by the Centre for Health Record Linkage. Results: Over a median of 5.4 years, 17,332 cancers were diagnosed. Increasing levels of alcohol intake were associated with increased risk of cancers of the upper aerodigestive tract (1.19; 1.10–1.29), mouth and pharynx (1.18; 1.08–1.29), oesophagus (1.22; 1.04–1.43), colorectum (1.09; 1.04–1.15), colon (1.13; 1.06–1.20), liver (1.22; 1.04–1.44) and breast (1.11; 1.02–1.21). Breast cancer risk was marginally associated with drinking pattern, with higher risk when intake was concentrated on 1–3 days/week compared to the same amount spread over 4–7 days (P_interaction = 0.049). Conclusions: Alcohol consumption confers a significant risk of cancer, and drinking pattern may be independently related to breast cancer risk.