Large Study Challenges Notion of Moderate Alcohol’s Cardiac Benefits

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Though light alcohol consumption may provide heart-related health benefits has been suggested observational research, a large study published in JAMA Network Open showed a link between all levels of alcohol intake and higher risks of cardiovascular disease. The researchers found that the supposed benefits of alcohol consumption may in fact be attributable to other healthy lifestyle factors common among light to moderate drinkers.

The study included 371 463 adult participants from the UK Biobank, average age 57 and consuming an average of 9.2 drinks per week. In line with previous findings, researchers found that the lowest heart disease risk was in light to moderate drinkers, followed by people who abstained from drinking. People who drank heavily had the highest risk. However, light to moderate drinkers also tended to have healthier lifestyles than abstainers, such as more physical activity and vegetable intake, and less smoking. One a few lifestyle factors were taken into account, any benefit associated with alcohol consumption was significantly reduced.

The study also used new techniques in Mendelian randomisation, which uses genetic variants to determine whether an observed link between an exposure and an outcome is consistent with a causal effect. “Newer and more advanced techniques in ‘non-linear Mendelian randomisation’ now permit the use of human genetic data to evaluate the direction and magnitude of disease risk associated with different levels of an exposure,” said senior author Krishna G. Aragam, MD, MS, a cardiologist at MGH and an associate scientist at the Broad Institute. “We therefore leveraged these new techniques and expansive genetic and phenotypic data from biobank populations to better understand the association between habitual alcohol intake and cardiovascular disease.”

When such genetic analyses were performed on samples taken from participants, they found that individuals with genetic variants that predicted higher alcohol consumption were indeed more likely to consume greater amounts of alcohol, and more likely to have hypertension and coronary artery disease. The analyses also revealed significant differences in cardiovascular risk across the spectrum of alcohol consumption for both males and females, with minimal risk increase when going from zero to seven drinks per week, much higher risk increases when progressing from seven to 14 drinks per week, and greatly increased risk for 21 or more drinks per week. Notably, the findings suggest a rise in cardiovascular risk even at “low risk” levels (ie below two drinks per day for men and one per day for women).

This discovery of an exponential rather than liner relationship between alcohol intake and cardiovascular risk is was supported by an additional analysis of data on 30 716 participants in the Mass General Brigham Biobank. Therefore, cutting back on large consumption of alcohol may have even more clinical benefits than cutting back on moderate amounts.

“The findings affirm that alcohol intake should not be recommended to improve cardiovascular health; rather, that reducing alcohol intake will likely reduce cardiovascular risk in all individuals, albeit to different extents based on one’s current level of consumption,” said Dr Aragam.

Source: Massachusetts General Hospital

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