Bias in beverage studies?

by Editorial Staff
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BOSTON — New research disparaging industry-funded beverage studies disregards the integrity of respected journals, according to the American Beverage Association.

The research from Children’s Hospital Boston, published on-line in the Jan. 9 issue of PLoS Medicine, found industry-funded beverage nutrition studies to be four to eight times more likely to have conclusions favorable to sponsors’ financial interest than non-industry funded studies. But according to the A.B.A., the research failed to look at the merits of the science in the studies and disregarded the integrity of the peer-review process enforced by the scientific journals.

"This is yet another attack on industry by activists who demonstrate their own biases in their review by looking only at the funding source and not judging the research on its merits," said Susan K. Neely, president and chief executive officer of the A.B.A. "The science is what matters — nothing else."

David Ludwig, the study’s senior author and director of the Optimal Weight for Life program at Children’s Hospital Boston, said the findings are critical, particularly for an industry that receives frequent media attention and helps influence government and professional dietary guidelines.

"We don’t all take drugs, but we eat every day," Mr. Ludwig said. "If the science base is compromised by conflict of interest, that’s a top-order threat to public health."

The researchers focused their analysis on literature about soft drinks, juice and milk during a five-year period (1999-2003). They analyzed 206 articles, which in order to be eligible had to look at health outcomes or disease markers, had to involve humans or human tissue, had to be classifiable as an interventional or observational study or a scientific review, and had to explicitly state the beverages’ effects on health measures. Of the 206 articles, 111 declared financial sponsorship.

Upon completion of their studies, the researchers found the odds ratio for having a favorable versus unfavorable conclusion was 4.37, increasing to 7.61 when beverage type, publication year and examination of authors’ personal conflicts of interest were taken into account.

Mr. Ludwig said the bias in the studies could take several forms, ranging from framing the questions in a way that makes the results more favorable to a sponsor to simply not publishing papers with unfavorable results.

He did note, though, that the findings don’t necessarily extend to nutrition studies as a whole.

"We chose beverages because they represent an area of nutrition that’s very controversial, that’s relevant to children, and involves a part of the food industry that is highly profitable and where research findings could have direct financial implications," he said.

Ms. Neely of the A.B.A. questioned the methodology of the review process.

"By not disclosing the studies examined, it is entirely possible that articles were excluded simply because they did not prove the authors’ point," Ms. Neely said. "In addition, a bias may be present by failing to disclose that one of the authors is actually on the editorial board of the publication."

Greg Miller, a nutrition biochemist who heads research for the National Dairy Council, pointed out that public health experts who promote dietary guidelines tend to be biased toward their own advice. He said the N.D.C. requires its funded researchers to publish results in journals that require review by outside scientists and to disclose who pays for their work.

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