CDC Study Skeptical on Moderate Drinking's Heart Benefit

By Katrina Woznicki
April 19, 2005

MedPage Today Action Points

• Advise patients that while a number of observational studies suggest that moderate drinking may lower cardiovascular disease (CVD) mortality, this population-based study suggests that one reason for these findings may be that 90% of CVD-associated risk are more prevalent among nondrinkers than moderate drinkers.
   
• Moderate drinking has not been found to be harmful, but the Centers for Disease Control and Prevention is suggesting it's earlier benefits may have been over-exaggerated as not all risk factors were controlled for.
   
• These researchers are not saying that there are no benefits from moderate alcohol consumption but rather they are injecting a skeptical note and emphasizing the need for randomized controlled clinical trials to determine alcohol's cardiovascular benefits.

Review

ATLANTA, April 19-A few drinks a day may not stave off the cardiologist after all, the federal government has warned.

Indeed, the benefits to cardiovascular health attributed to moderate consumption of alcohol may well be the result of other lifestyle or biological factors, said a study by the Centers for Disease Control and Prevention that was released today.

"If we compared this (alcohol) to a pharmaceutical drug, there's no way in hell the FDA would've approved it," said Tim Naimi, M.D., an internist and medical epidemiologist at the CDC's Chronic Disease Center, in an interview.

Moderate alcohol consumption should not be recommended to improve cardiovascular health, he added. "It should be viewed with extreme caution because there are no randomized studies on it."

Dr. Naimi and his team analyzed data from 250,000 American adults who participated in a 2003 telephone survey and found nondrinkers had a higher risk for heart disease because they had higher rates of hypertension, diabetes, inactivity, and obesity compared with moderate drinkers.

Participants were asked about socioeconomic status, smoking, medical conditions, lifestyle, marital status, race, even the number of teeth they had. Of the 30 factors assessed in the survey, 90% were significantly more common among nondrinkers than moderate drinkers.

"Moderate drinkers have lot of favorable lifestyle characteristics," Dr. Naimi said, including better socioeconomic status, more education, and overall better general health than nondrinkers, who tend to be poorer.

"They're so fundamentally different from one another in so many ways other than their alcohol consumption," Dr. Naimi said. "You're not comparing apples to apples. You're comparing apples to oranges."

Based on these findings, which are published in the May issue of American Journal of Preventive Medicine, Dr. Naimi said, Americans should not be encouraged to think a glass or two of wine, beer, or spirits is going to protect their hearts.

Several studies came out over the past decade upholding the virtues of the French paradox and the potential heart-health benefits of the occasional cocktail. But Dr. Naimi said alcohol's benefits might have been oversold, much like the pros of vitamin E and hormone replacement therapy were.

Vitamin E and hormone replacement therapy were found to be "completely useless in randomized trials," Dr. Naimi said. To determine alcohol's true benefits, randomized clinical trials would need to be conducted, he added.

"The public was sold a bad bill of goods with the whole vitamin E and hormone replacement therapy thing," he said. "They're a cautionary tale. If we sell them a bad bill of goods with alcohol, we're going to cause a lot of damage to a lot of people."

Dr. Naimi said that 30% of all U.S. drinkers drink excessively.

"We're not saying moderate drinking has no benefits for people," Dr. Naimi said. The CDC just wanted to interject a "justified and healthy dose of skepticism."

Primary source: American Journal of Preventive Medicine
Source reference: Naimi et al. Cardiovascular Risk Factors and Confounders Among Nondrinking and Moderate-Drinking U.S. Adults. Amer J Prev Med. 2005; 28:369-373.