- The Washington Times - Wednesday, August 2, 2017

While a raft of studies link moderate drinking with various health benefits, a noted British researcher warns that such findings must be viewed in context of the studies’ limitations.

Anya Topiwala, a clinical lecturer in old age psychiatry at the University of Oxford, is the lead author of a recently published study on the deleterious effects of alcohol on the brain. The study, which was published in June in The British Medical Journal, found that even moderate consumption of alcohol can cause brain damage.

In an interview with The Washington Times, Dr. Topiwala urged caution toward studies reporting health benefits of moderate drinking, saying the general public must pay attention to those studies’ limitations before accepting their results.

For instance, a recently published Danish study evaluated more than 70,000 people over four years to explore how alcohol consumption relates to diabetes risk. The Danish researchers concluded that three or four drinks per week were associated with the lowest risk of diabetes in their study’s participants, but they did not find that moderate drinking prevents the disease, she said.

“The evidence for protective effect on cardiovascular health has been stronger than on the brain,” Dr. Topiwala said, “but even there — with some of the more recent, better done studies — they haven’t found the protective effect.”

Other limitations include short time spans for the research: In another study purporting to show alcohol consumption’s benefits in memory retention, the experiment took place over 48 hours, she said. In that study, participants did a better job on a memory recall test the day after drinking than they had performed before they started drinking.

In addition, confounding factors like education or socioeconomic status can account for subjects being conscious of taking care of their health overall, Dr. Topiwala said.

Another problem researchers face is study participants self-reporting their alcohol consumption, particularly if alcohol consumption or other health problems already have affected one’s memory, she said.

Dr. Topiwala admitted that it’s difficult to overcome some of these limitations even in her own research. In her most recently published study, she and her team evaluated more than 500 people over 30 years — starting in midlife — and focused on brain-imaging scans to evaluate any damaged parts that could be a result of alcohol consumption.

In deciding to embark on her study, Dr. Topiwala said she felt existing evidence on the negative effects of alcohol on the brain wasn’t strong enough.

“There were only a few studies that used brain imaging, and they were quite small,” she said. “There were some limitations to their methods and the results were quite conflicting. So we thought it was kind of an unanswered question still.”

To account for some of the limitations already noted, the researchers had their subjects update their reported alcohol consumption routinely over a period of every five years and routinely checked the subjects’ cognitive performance.

Among the data, the researchers found that light drinkers — those who consume less than seven units of alcohol a week — had no protective health effects and even showed signs of damage to the hippocampus, the area of the brain associated with memory.

“Alcohol consumption, even at moderate levels, is associated with adverse brain outcomes including hippocampal atrophy,” the researchers wrote in their study. “These results support the recent reduction in alcohol guidance in the UK and question the current limits recommended in the U.S.”

“Clearly, this is just one study — although a large one, and attention needs to be paid to it — but obviously I want to look further into this question in other populations and larger samples,” Dr. Topiwala said.

The Centers for Disease Control and Prevention considers moderate alcohol consumption as one drink per day for a woman and two drinks for a man.

According to the 2015 National Survey on Drug Use and Health, an estimated 138.5 million Americans over the age of 12 consumed alcohol in the 30 days before the survey — a little more than half of the U.S. population.

 

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