Setting the Record Straight

As uncertainty reigns and constitutional scholars speculate that we may be "sleepwalking into autocracy," I was glad to find some comfort recently in listening to Dr. Marty Makary on Peter Attia's The Drive podcast. Makary is Trump's nominee to lead the U.S. Food and Drug Administration. Like FDA Commissioner Scott Gottlieb in the first Trump Administration, Dr. Makary boasts impressive credentials as a medical authority. Only time will tell if he has the leadership acumen, motivation, and the stamina, to reform FDA's foods program, but he talks a good talk.

On the podcast, recorded last September, Makary discussed his latest book, "Blind Spots: When Medicine Gets It Wrong, and What It Means for Our Health." The book takes a critical look at the American Academy of Pediatrics ill-conceived recommendation for pregnant and lactating mothers and children zero to three years old to completely avoid peanuts. AAP issued the recommendation in 2000, a couple years after health authorities in the United Kingdom did the same. The results were disastrous. Peanut allergies skyrocketed, and AAP eventually reversed its recommendation, but only after 17 years, and two years after immunologists published the results of a randomized clinical trial showing that infants exposed to peanuts were 86 percent less likely to develop a peanut allergy.

For Makary, the AAP researchers responsible for the errant recommendation should have done more, earlier to correct their mistake. "Why not reverse the recommendation with the same vigor with which you put it out initially?" he asks. He makes a good point.

As I listened, I could not help but think of the decades of official advice on "moderate drinking" to consumers. As Marion Nestle summed up in a recent post, the Dietary Guidelines for Americans have assured consumers since 1980 that "one or two drinks daily" are harmless. Many iterations of the Guidelines, which are updated every five years, touted questionable evidence that moderate drinking reduces cardiovascular risk, while largely ignoring the mounting evidence that consuming alcohol, in any amount, increases cancer risk.

This advice was spurred on by observational studies finding that "light" or "moderate" drinkers tend to live longer than "abstainers." But newer research belies the notion that this association reflects any health benefits associated with drinking alcohol. Rather, "selection biases, reverse causation, and residual confounding" appear to account for "moderate" drinkers apparent longevity.

As researcher Rosario Ortolá and colleagues explain in a recent JAMA article:

"Selection biases are often overlooked, but they can lead to a systematic underestimation of alcohol-related burden. That is the case of the abstainer bias, whereby the apparently lower mortality of light drinkers compared with abstainers could be explained by the higher death risk of the abstainers because they include former drinkers who quit alcohol due to poor health, as well as lifetime abstainers, who often have worse lifestyle and health characteristics than regular drinkers. Also, the healthy drinker/survivor bias, caused by overrepresentation of healthier drinkers who have survived the deleterious effects of alcohol, can distort comparisons, especially in older age."

How can researchers account for these biases and confounders? One strategy, used in Ortola's analysis of 135,103 drinkers in the United Kingdom, uses "occasional drinkers instead of abstainers" as a reference group. Using this baseline, even the "low risk" drinkers-defined as men drinking less than two standard drinks per day on average (20 grams alcohol/day) and women drinking less than one (10 grams alcohol/day)-had higher all-cause mortality than the reference group, and significantly higher cancer mortality. In general, the researchers found that drinking more, at any level, harmed health.

New "Mendelian randomization" studies, which compare populations with genetic variants associated with lower alcohol consumption - and thus avoid many of the selection biases that characterize older studies comparing abstainers and "light" or "moderate" drinkers - tell a similar story. The 2020 Dietary Guidelines Advisory Committee (DGAC) cited those studies in its report recommending a "drink less" message and, specifically, that the DGAs abandon the endorsement of a two drinks per day "moderate drinking" cap for men.

But of course, the DGAs did not abandon the "two a day for men" advice, because the first Trump Administration's political appointees overruled the scientific experts. The alcohol industry and its lobbyists went on to convince Congress to step in and strip away alcohol from the DGAC's consideration-which is why the latest Committee's report contains no recommendation on the topic. Instead, Congress appropriated $1.3 million to the National Academies of Sciences, Engineering and Medicine (NASEM) to convene a panel on alcohol's health effects.

The NASEM panel, criticized for including researchers with financial ties to the alcohol industry, issued its report just in time for Christmas. The report casts doubt on the emerging consensus that any level of alcohol consumption causes harm, but only by excluding most of the relevant studies on the topic. Even so, it acknowledges that moderate alcohol consumption increases breast cancer risk, and possibly colon cancer risk, although it breaks from the National Cancer Institute's findings that moderate alcohol consumption also increases esophageal, head and neck cancer risk.

To start off the new year, the Surgeon General gave us an advisory on alcohol and cancer risk. The advisory reviews the evidence that led to the National Cancer Institute's and others' conclusion that even light drinking causes various cancers, including a discussion of the mechanisms by which alcohol, long known to be a carcinogen, is thought to cause cancer. It recommends a cancer warning on alcoholic beverages. As CFA has argued in support of such a warning, the Surgeon General's advisory emphasizes the evidence that alcohol causes a large number of cancer deaths-even more than UV radiation-and that public awareness of the link is very low, with fewer than half of adults recognizing alcohol increases cancer risk.

Now, following on the heels of the Surgeon General's advisory, an expert panel of the Interagency Coordination Committee on the Prevention of Underage Drinking (ICCPUD) has released its draft report on alcohol and health. Unlike the NASEM committee, this committee did not include researchers that received funding from the alcohol industry. Unlike the NASEM committee, it did not receive a special mandate from Congress; rather, the alcohol industry's allies in Congress attempted to muzzle it. And unlike the NASEM committee, which looked at associations between "all cause" mortality and alcohol use, the ICCPUD panel looked specifically at mortality related to "health conditions causally related to alcohol use."

The ICCPUD report makes clear that even a little drinking causes harm. It concludes that "the risk of dying from alcohol use begins at low levels of average use," for U.S. consumers, and specifically that "males and females have a 1 in 1000 risk of dying from alcohol use if they consume more than 7 drinks per week," but that risk "increases to 1 in 100 if they consume more than 9 drinks per week."

Will this be enough to roll back the bad advice that the DGAs have given us for the past 45 years? The last Trump Administration ignored the science on alcohol. How it handles the issue this time around may give an early indication of what we can expect the next four years.

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