Clinical Trials of Vitamin Supplements: Are They Meeting the European Medicines Agency Prompt Dissemination Regulation?

Abstract

Vitamin supplements are over-the-counter medications consumed by the majority of adults. Given that many supplements may be ineffective and/or associated with adverse events, compliance of the registered trials to the European Medicines Agency (EMA) rule for prompt reporting of the results is of crucial importance for consumers’ health. The present retrospective study was designed to evaluate compliance with the European Union (EU) requirement to post the trial results to the EU Clinical Trials Database (EudraCT) and assess the trial characteristics associated with this compliance. Three independent researchers searched the EudraCT for completed trials on vitamin supplements performed on humans. A total of 144 completed trials involving 40,464 participants fulfilled the inclusion criteria. For 45.7% of these, results were due. Trials funded by the industry had approximately quadruple chances of being published, adjusting for their design, masking, comparator, and participant age group. Moreover, trials testing vitamin supplement safety are more likely to report their findings as compared to vitamin efficacy. Many vitamin supplementation trials registered in the EudraCT failed to report their results and adhere to the EMA regulations. Stricter regulations should be imposed concerning trial results reporting to increase transparency and public trust.

A Meta-Epidemiological Study of Positive Results in Clinical Nutrition Research: The Good, the Bad and the Ugly of Statistically Significant Findings

“…Furthermore, specific standards have been proposed for observational nutrition research based on the Strengthening the Reporting of Observational Studies in Epidemiology-Nutritional Epidemiology (STROBE-nut) guidelines [ 48 ]. Nonetheless, even when protocols have been published, they are not always followed, and frequently, as seen in the case of vitamin intervention trials [ 7 ], they fail to post their results promptly, possibly due to negative findings. Recent research showed that poor reporting quality is also extended in basic nutrition research performed on mice, where the majority of scientists appear oblivious to the reporting checklists for animal research [ 49 ].…”

“…Nevertheless, nutrition research has often been questioned for “cherry picking” significant findings [ 6 ], being pedaled by the industry [ 7 , 8 , 9 ] or for failing to follow the rules of nutritional epidemiology for correcting common nutrition bias [ 10 , 11 ]. For instance, the Hawthorne effect [ 12 ], an indisputable component of all nutrition research, can be diminished by distinguishing the participants to adequate-, over- or low-energy reporters [ 13 , 14 ].…”