In a recent study published in The Lancet, researchers performed a population-scale analysis of alcohol consumption by amount, age, gender, region, and year to estimate the theoretical minimum risk exposure level (TMREL) and the non-drinker equivalence (NDE).
The former is associated with minimizing health loss, and the latter presents a risk to health for a drinker compared to a non-drinker.
Alcohol consumption claimed 1.78 million lives in 2020 and emerged as a leading cause of death in 15 to 49-year-old males. The consequences of alcohol use on general health are complex, and multiple studies have associated it with an increased risk of liver cirrhosis, cancer, injuries, and tuberculosis. However, the amount of alcohol that minimizes health loss varies widely by geography, age structure, sex, and disease burden of that population.
Previously done systematic meta-analyses considered a few health outcomes associated with alcohol consumption and showed a J-shaped relationship between alcohol use and all-cause mortality. The differences in study covariates, methods, individual-level health outcomes, and issues with selection bias, together, resulted in uncertainty about the effect of alcohol on all-cause health loss. More importantly, studies did not account for background rates of disease while analyzing the effects of alcohol consumption on all-cause mortality.
About the study
In the present study, researchers reported the association between alcohol consumption and the health outcomes due to alcohol use accounting for the highest number of global disability-adjusted life-years (DALYs), the sum of life years lost, and years lived with disability. Based on 22 health outcomes of burden-weighted alcohol dose–response relative risk curves, they estimated the TMREL and NDE; and presented up to three figures as standard drinks per day. One standard drink referred to 10 g of pure ethanol consumption.
The researchers also quantified the population consuming harmful amounts of alcohol based on the NDE values. This quantification helped adjust for under-reported alcohol consumption due to bias, unrecorded alcohol consumption, and consumption among tourists. The team based uncertainty in the relative risk curve on 1000 draws of each cause-specific relative risk curve and DALY rates.
The team searched PubMed and other published meta-analyses up to December 31, 2019, to obtain study data. They used search terms such as alcohol, drinking behavior, risk, hazard ratio, etc., and limited their search to only English publications. Further, the team used disease background rates from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2020. The GBD data encompassed 21 regions, including 204 countries; moreover, data were stratified based on age groups, gender, and year for the 15–95 year age group, from 1990 to 2020.
In 2020, among individuals of the 15–39 year age group, the TMREL and NDE varied between zero and 0.603 and 0.002 and 1.75 standard drinks per day, respectively. In those over 40 years, the TMREL and NDE varied between 0.114 to 1.87 and 0.193 and 6.94 standard drinks per day, respectively. Of those who were consuming alcohol in harmful amounts in 2020, 59·1% were in the 15–39 age group, and 76.9% were male.
According to the authors, the present study is the first to evaluate variations in the minimum risk of alcohol consumption by region, age, gender, and time, based on background disease rates. Typically studies make these recommendations based on all-cause mortality or a cause-specific outcome, thus, complicating the interpretation of alcohol consumption risk. Moreover, these studies did not account for the causes of all-cause mortality that could differ substantially between populations.
The study highlights the need to consider the background rates of diseases and injuries for each population before releasing the guidelines and recommendations on the optimal level of alcohol consumption, e.g., in young adults, the level of alcohol consumption that minimizes health loss is close to zero. Likewise, elderly populations of many global regions with a high burden of cardiovascular diseases show improved health outcomes with small amounts of alcohol consumption.
Therefore, the study authors recommended changes in the existing policy guidelines and emphasized on recommending differential optimal alcohol consumption levels by age and gender. Nevertheless, the interventions targeted toward younger adults are needed to reduce the global health loss due to alcohol consumption.