HerbalEGram: Volume 5, Number 5, May 2008

A study published in the online journal BMC Complementary and Alternative Medicine in April has found that there may be a correlation between the amount of pharmaceutical advertising that a medical journal contains and its editorial content concerning dietary supplements.

For the study, researchers recorded instances of pharmaceutical advertisements (including ads for prescription drugs, over-the-counter medications, and drug-eluting stents) and dietary supplement editorial content (including clinical trials, cohort studies, editorials and reviews, abstracts, letters, news stories, patient information blurbs, or meeting notes) in all issues published within a 1-year time span of 11 major medical journals. The 11 selected journals focus on general medicine, internal medicine or pediatrics, and issues spanned from June 2006 through June 2007. The authors of the article defined dietary supplements according to the definition used by the US Food and Drug Administration, and they also included content on tea and coffee since such articles tended to focus on caffeine or antioxidant values. The dietary supplement content was evaluated for conclusions regarding safety and effectiveness, when possible.

According to the authors’ results, the average number of pharmaceutical ads varied from 0.15 to over 60 pages per issue, and the amount of dietary supplement editorial content ranged from 4 to 61 instances per journal. The journals with the most pharmaceutical ads published fewer major articles about dietary supplements (i.e., original research, editorials, reviews) per issue than journals with a medium level of such ads, and journals with the fewest pharmaceutical ads published the most major dietary supplement articles. Journals with the most pharmaceutical advertising were also significantly more likely to publish major articles concluding that dietary supplements were unsafe than journals with a medium or low level of pharmaceutical advertising.

The authors also assessed the pharmaceutical advertising and dietary supplement editorial content of 3 journals devoted to complementary and alternative medicine (CAM). They found that the CAM journals contained no advertisements for prescription pharmaceuticals, although they did contain ads for dietary supplements. The journals further contained significantly more articles about dietary supplements than the 11 primary journals. The proportion of major articles concluding that dietary supplements were unsafe or ineffective, however, was not significantly different from the primary journals with medium or low levels of pharmaceutical advertising.

“I think the study adds to the large body of evidence that advertising influences human behavior,” said lead author Kathi Kemper, MD, Caryl J Guth Chair for Complementary and Integrative Medicine at Wake Forest University School of Medicine (e-mail, April 23, 2008). “There’s a lot of data that ads influence consumers, researchers, writers. There has not been as much about editorial decisions, for obvious reasons. We were careful to include not only the big names (Journal of the American Medical Association, New England Journal of Medicine, and British Medical Journal) but also the Canadian Medical Association Journal and American Family Physician, which mostly feature review articles. These journals still have large influence in physician practice and dissemination of best practices/guidelines, etc.”

The study’s results were consistent with the authors’ hypothesis that pharmaceutical advertising may bias journals against non-drug therapies. Dr. Kemper expressed that she was surprised that they didn’t find a stronger association between journals’ amount of pharmaceutical advertisements and editorial content portraying a lack of effectiveness of dietary supplements, although she added that the study utilized a relatively small sample size in terms of reviewed journals.

“A larger study really needs to be done,” said Dr. Kemper. “Also, we didn’t look at what was submitted to journals, their quality, etc. We didn’t ask journal editors how they made decisions, how many papers they’d rejected, which sorts, etc. There is a lot of room for additional research.”

—Courtney Cavaliere

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