A new study of alcohol use in countries of all income levels shows that current use increases the risk of alcohol-related cancers and injury, with no reduction in risk of mortality or cardiovascular disease overall. The research supports health strategies to reduce harmful alcohol use, especially in low-income countries (LICs).
Alcohol consumption is proposed to be the third most important modifiable risk factor for death and disability. However, alcohol consumption has been associated with both benefits and harms, and previous studies were mostly done in high-income countries.
This new study investigated associations between alcohol consumption and clinical outcomes in a prospective cohort of countries at different economic levels in five continents. The data came from 12 countries participating in the Prospective Urban Rural Epidemiological (PURE) study, a prospective cohort study of individuals aged 35-70 years. The high-income countries (HICs) were Sweden and Canada; upper-middle-income countries (UMICs) were Argentina, Brazil, Chile, Poland, South Africa, and Turkey; lower-middle-income countries (LMICs) were China and Colombia; and LICs were India and Zimbabwe.
The study included 114,970 adults, of whom 12 904 (11%) were from HICs, 24 408 (21%) were from UMICs, 48 845 (43%) were from LMICs, and 28 813 (25%) were from LICs. The median follow-up was 4•3 years and current drinking was reported by 36,030 (31%) individuals. Although current drinking was associated with a 24% reduced risk of heart attack, there was no reduction in risk of mortality or stroke, and current drinking was associated with a 51% increased risk of alcohol-related cancers – meaning those of the mouth, oesophagus, stomach, colorectum, liver, breast, ovary, and head and neck – and a 29% increased risk of injury in current drinkers. For a combination of all reported outcomes, there was no overall benefit from current alcohol use. High alcohol intake and heavy episodic drinking were both associated with significant increases in risk of overall mortality.
The authors also identified differences between countries of different income levels in risk for a combination of all clinical outcomes analysed in the study (mortality, cardiovascular disease, stroke, heart attack, cancer, injury, and admission to hospital). For higher-income countries (HICs/UMICs combined), current drinking was associated with a 16% reduced the risk of this combined outcome, while for lower-income countries (LMICs/LICs combined) current drinking was associated with a 38% increased risk.
Lead author Dr Andrew Smyth of the Population Health Research Institute, McMaster University, Canada says: “Our data support the call to increase global awareness of the importance of harmful use of alcohol and the need to further identify and target the modifiable determinants of harmful alcohol use.” Co-author Dr Salim Yusuf, director of PHRI and president of World Heart Federation adds: “Because alcohol consumption is increasing in many countries, especially in LICs/LMICs, the importance of alcohol as a risk factor for disease might be underestimated. Therefore, global strategies to reduce harmful use of alcohol are essential.”
Writing in a linked comment, Dr Jason Connor of the Centre for Youth Substance Abuse Research, University of Queensland, and Professor Wayne Hall of the Centre for Youth Substance Abuse Research, University of Queensland, Brisbane, Australia and National Addiction Centre, Kings College London, UK, say: “More than sufficient evidence is available for governments to give increased public health priority to reducing alcohol-related disease burden in low-income and middle-income countries. This should be done by implementing the most effective population policies to discourage harmful drinking–namely, increasing the price of alcohol and reducing its availability, especially to younger drinkers, and preventing the alcohol industry from promotion of frequent drinking to intoxication.”
Alcohol consumption is proposed to be the third most important modifiable risk factor for death and disability. However, alcohol consumption has been associated with both benefits and harms, and previous studies were mostly done in high-income countries. We investigated associations between alcohol consumption and outcomes in a prospective cohort of countries at different economic levels in five continents.
We included information from 12 countries participating in the Prospective Urban Rural Epidemiological (PURE) study, a prospective cohort study of individuals aged 35–70 years. We used Cox proportional hazards regression to study associations with mortality (n=2723), cardiovascular disease (n=2742), myocardial infarction (n=979), stroke (n=817), alcohol-related cancer (n=764), injury (n=824), admission to hospital (n=8786), and for a composite of these outcomes (n=11 963).
We included 114 970 adults, of whom 12 904 (11%) were from high-income countries (HICs), 24 408 (21%) were from upper-middle-income countries (UMICs), 48 845 (43%) were from lower-middle-income countries (LMICs), and 28 813 (25%) were from low-income countries (LICs). Median follow-up was 4•3 years (IQR 3•0–6•0). Current drinking was reported by 36 030 (31%) individuals, and was associated with reduced myocardial infarction (hazard ratio [HR] 0•76 [95% CI 0•63–0•93]), but increased alcohol-related cancers (HR 1•51 [1•22–1•89]) and injury (HR 1•29 [1•04–1•61]). High intake was associated with increased mortality (HR 1•31 [1•04–1•66]). Compared with never drinkers, we identified significantly reduced hazards for the composite outcome for current drinkers in HICs and UMICs (HR 0•84 [0•77–0•92]), but not in LMICs and LICs, for which we identified no reductions in this outcome (HR 1•07 [0•95–1•21]; pinteraction<0•0001).
Current alcohol consumption had differing associations by clinical outcome, and differing associations by income region. However, we identified sufficient commonalities to support global health strategies and national initiatives to reduce harmful alcohol use.