Disclosure of funding sources and conflicts of interest in evidence underpinning vitamin D and calcium recommendations in bone health guidelines

Abstract

Objective: The present study aims to examine the relationship between study funding sources, author conflicts of interest and conclusions in studies supporting vitamin D and calcium intake cited in bone health guideline recommendations. Design: Cross-sectional Setting: 47 global bone health guidelines with vitamin D and/or calcium recommendations for adults aged 40 years and above Participants: The evidence cited to support the recommendations was extracted by two independent reviewers and classified by type of recommendation, article characteristics, study design, types of funding sources and conflict of interest (COI) disclosure and direction of study conclusions. Results: Of 156 articles cited to support the bone health recommendations, 120 (77%) disclosed a funding source, and 43 (28%) declared that at least one author had a COI. Compared with articles with non-commercial or no funding source, those funded by commercial sponsors tended to have a study conclusion favourable towards vitamin D/calcium [RR (95% CI): 1.32 (0.94, 1.87), p = 0.16], but the association was not statistically significant (Fisher’s exact test). Compared to those with a COI disclosure statement, articles with missing or unclear COI disclosure were more likely to have favourable conclusions [1.56 (1.05, 2.31), p = 0.017] (Fisher’s exact test). Conclusion: In the evidence underpinning a sample of global bone health guidelines, COI disclosure was low and studies with missing or unclear COI disclosures were more likely to have favourable study conclusions than those with disclosures, suggesting a need for greater transparency of COI in bone health guidelines.

Conflict of Interests in the Scientific Production on Vitamin D and COVID-19: A Scoping Review

“…Previous studies in other fields have also found an absence of COI disclosures, as well as reports of “no disclosures” by authors who had financial relationships with industries, characterizing omission ( 56 ). A recent study that analyzed the evidence supporting global guidelines for vitamin D and calcium recommendations in bone health showed that COI disclosure was low, and studies with absent or unclear COI disclosures were more likely to come to conclusions favorable to vitamin D and/or calcium intake than those with disclosures ( 57 ). In our review we found a lack of clear statements regarding the origins of funding, the sponsor's role in the study as well as a lack of bias and limitations in reporting.…”