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

Abstract

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.

Trial registration: ClinicalTrials.gov NCT02328872.

Fig. 1. Hazard ratios (HR) and 95% confidence intervals (CI) of cancer risk per seven-drink increase in weekly alcohol consumption among drinkers in the 45 and Up Study (2006–2013).

Linear trend calculated among drinkers only, where participants within each category of alcohol consumption at baseline were assigned the mean level of alcohol consumption they reported at first-wave follow-up (median 5.3 years after baseline). Models were adjusted for cancer-specific covariates as listed in Supplementary Table 1. Cancer cases do not sum to totals as some participants were diagnosed with two or more primary cancers. ARCC alcohol-related cancers combined.

Fig. 2. Estimated cumulative absolute risk (%) of an alcohol-related cancer diagnosis from age 25 to 85 years in Australia in 2014 by sex and level of alcohol consumption using hazard ratios from the 45 and Up Study (2006–2013).

This calculation was based on the results of the continuous variable analysis among 45 and Up Study participants who consumed ≥1 drink per week. Three categories of drinking were used: 0 to <1 drink per week (never-drinkers, former drinkers and occasional drinkers who consumed <1 drink per week), ≥1 to ≤14 drinks per week (median 6 drinks in men and 5 drinks in women) and >14 drinks per week (median 21 drinks in men and 20 drinks in women). Note: Incidence data for alcohol-related cancers combined included International Classification of Diseases version 10 codes C30–31 while hazard ratio calculations did not.

Fig. 3. Hazard ratios (HR) and 95% confidence intervals (CI) of cancer risk by drinking pattern among participants consuming ≥ 4 drinks per week in the 45 and Up Study (2006–2013).

Models were adjusted for cancer-specific covariates as listed in Supplementary Table 1. Reference category: ≥4 to <7 drinks per week, consumed on 4–7 days per week. Point estimates plotted at mean intake for each of the three levels of overall alcohol consumption (≥4 to <7 drinks per week, ≥7 to <14 drinks per week and ≥14 drinks per week). P_interaction is for test of interaction between days per week and drinks per week. Breast cancer in women only.