Does moderate drinking protect your heart? A genetic study offers a new answer.
The investigators’ statistical analysis showed an exponential curve of risk with genetic variants that suggest they drink more. The risks of heart disease and high blood pressure started slowly as the number of drinks increased, but they quickly escalated, skyrocketing as people entered the drinking range of 21 drinks. or more per week.
The actual risks for an individual depend on whether the person has other conditions, such as diabetes or obesity. But, Dr. Aragam said, extrapolating from the study results, a typical middle-aged person in the study who wasn’t drinking had about a 9% chance of having coronary heart disease. A person who drank one drink a day had about a 10.5% chance, which is low. After that, however, the risk increases rapidly.
Many previous studies of alcohol consumption and heart health were observational, meaning subjects were followed over time to see if the amount of alcohol was related to heart health.
Such studies can only find correlations but not causation, the researchers say. But the Biobank study’s use of Mendelian randomization suggests more causation, and its findings may therefore carry more weight.
“We need to start thinking about these moderate ranges and informing patients accordingly,” Dr. Aragam said. “If you choose to drink, be aware that beyond a certain level the risk increases a bit. And if you choose to drink less, you’ll get most of your benefits if you go down to seven drinks a week.
Dr. Amit V. Khera, study author and cardiologist at Verve Therapeutics, said that, of course, the gold standard for assessing the cardiac effects of alcohol consumption would be a large randomized clinical trial. Such a study, which would have randomized high-risk people to one drink a day or abstinence, was planned for 2017 by the National Institutes of Health. But it was halted because the researchers had inappropriate contact with the alcohol industry when planning the study.
Mendelian randomization techniques, Dr. Khera said, “are particularly useful when a gold standard has not been or cannot be made.”