Industrial support of biomedical research may bias scientific conclusions, as demonstrated by recent analyses of pharmaceutical studies. However, this issue has not been systematically examined in the area of nutrition research. The purpose of this study is to characterize financial sponsorship of scientific articles addressing the health effects of three commonly consumed beverages, and to determine how sponsorship affects published conclusions.
Methods and Findings
Medline searches of worldwide literature were used to identify three article types (interventional studies, observational studies, and scientific reviews) about soft drinks, juice, and milk published between 1 January, 1999 and 31 December, 2003. Financial sponsorship and article conclusions were classified by independent groups of coinvestigators. The relationship between sponsorship and conclusions was explored by exact tests and regression analyses, controlling for covariates. 206 articles were included in the study, of which 111 declared financial sponsorship. Of these, 22% had all industry funding, 47% had no industry funding, and 32% had mixed funding. Funding source was significantly related to conclusions when considering all article types (p = 0.037). For interventional studies, the proportion with unfavorable conclusions was 0% for all industry funding versus 37% for no industry funding (p = 0.009). The odds ratio of a favorable versus unfavorable conclusion was 7.61 (95% confidence interval 1.27 to 45.73), comparing articles with all industry funding to no industry funding.
Industry funding of nutrition-related scientific articles may bias conclusions in favor of sponsors' products, with potentially significant implications for public health.
In 111 scientific articles on nonalcoholic beverages, articles with all industry funding were more than 7 times more likely to have favorable conclusions compared with articles with no industry funding.
Much of the money available for doing medical research comes from companies, as opposed to government agencies or charities. There is some evidence that when a research study is sponsored by an organization that has a financial interest in the outcome, the study is more likely to produce results that favor the funder (this is called “sponsorship bias”). This phenomenon is worrying, because if our knowledge about effectiveness and safety of medicines is based on biased findings, patients could suffer. However, it is not clear whether sponsorship bias extends beyond research into drugs, but also affects other types of research that is in the public interest. For example, research into the health benefits, or otherwise, of different types of food and drink may affect government guidelines, regulations, and the behavior patterns of members of the public. Were sponsorship bias also to exist in this area of research, the health of the wider public could be affected.
Why Was This Study Done?
There is not a great deal of evidence about whether sponsorship bias affects nutritional research (scientific studies that look at the relationship between food and/or drink, and health or disease states). Therefore, the group of researchers here set out to collect information from published nutritional research papers, to see if the type of sponsorship for the research studies was in any way linked with whether the main conclusions were favorable or unfavorable to the sponsor.
What Did the Researchers Do and Find?
The research study reported here used the scientific literature as a source of data. The researchers chose to examine one particular area of nutrition (nonalcoholic drinks including soft drinks, juices, and milk), so that their investigation would not be affected too much by variability between the different types of nutritional research. Using literature searches, the researchers identified all original research and scientific review articles published between January 1999 and December 2003 that examined soft drinks, juices, and milk; described research carried out in humans; and at the same time drew conclusions relevant to health or disease. Then, information from each published article was categorized: the conclusions were coded as either favorable, unfavorable, or neutral in relation to the health effects of the products being studied, and the article's funding was coded as either all industry (ie, food/drinks companies), no industry, or mixed. 206 published articles were analyzed and only 54% declared funding. The researchers found that, overall, there was a strong association between the type of funding available for these articles and the conclusions that were drawn. Articles sponsored exclusively by food/drinks companies were four to eight times more likely to have conclusions favorable to the financial interests of the sponsoring company than articles which were not sponsored by food or drinks companies.
What Do These Findings Mean?
These findings suggest that a high potential for bias exists in research into the health benefits or harms of nonalcoholic drinks. It is not clear from this research study why or how this bias comes about, but there are many different mechanisms that might cause it. The researchers suggest that certain initiatives might help to reduce bias, for example, increasing independent funding of nutrition research.
Please access these Web sites via the online version of this summary at http://dx.doi.org/doi:10.1371/journal.pmed.0040005.
Conflict of Interest definition from Wikipedia (Wikipedia is an internet encyclopedia that anyone can edit)
The International Committee of Medical Journal Editors provides standard guidelines for practices at medical journals, including a section on sponsorship, authorship, and accountability
The Committee on Publication Ethics is a forum for journal editors to discuss issues related to the integrity of the scientific record, and it provides guidelines for editors and case studies for reference
The Good Publication Practice guidelines outline standards for responsible publication of research sponsored by pharmaceutical companies