Nutrition studies' conclusions tied to funding source

A systematic analysis of the medical literature shows that nutrition studies'' conclusions correlate with who funds them "“ much like the bias found for pharmaceutical studies, but with potentially greater public health implications.

Recent analyses have documented bias in pharmaceutical studies funded by industry. Now, an analysis from Children's Hospital Boston finds a similar phenomenon in scientific articles about nutrition, particularly in studies of beverages.

The analysis "“ the first systematic one performed on nutrition studies "“ found that beverage studies funded solely by industry were four to eight times more likely to have conclusions favourable to sponsors' financial interest than were studies with no industry funding.

David Ludwig, MD, PhD, the study's senior author and director of the Optimal Weight for Life (OWL) program at Children's Hospital Boston, believes that bias in nutrition studies may have far greater effects than bias in pharmaceutical studies. Not only do the findings of nutrition studies receive frequent media attention, but they influence governmental and professional dietary guidelines, the design of intervention programs, and FDA regulation of health claims on foods and beverages.

"We don't all take drugs, but we eat every day," Ludwig said.

"If the science base is compromised by conflict of interest, that's a top-order threat to public health."

Because the researchers focused their analysis on soft drinks, juice and milk, they aren't sure whether their findings 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," Ludwig said.

When analysed statistically, article conclusions were significantly related to funding source. Interventional studies with all-industry funding were much less likely to have unfavourable conclusions than those with no industry funding (0 v 37%).

Among all types of studies, comparing all-industry versus no-industry funding, the odds ratio for having a favourable versus unfavourable 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.