Assessing conflict of interest reporting and quality of clinical trials on infant formula: a systematic review

Objective This study aims to assess the quality, risk of bias, and conflicts of interest of clinical trials conducted on the effects of fortified infant formula. Study Design Systematic review including all randomized clinical trials targeting healthy children and using three arms: fortified infant formula; standard formula; and breastfeeding. We performed a descriptive analysis of the studies reviewed, assessed their quality using the “Risk-of-Bias 2” tool, and identified conflicts of interest. Results A total of 40 studies were included. All showed a high overall risk of bias, with this being especially noteworthy in the “Deviations from intention to treat” and “Missing outcome data” domains. 29 studies reported conclusions in favor of fortified formula; 15 studies reported multiple conclusions that were either contradictory or not in line with the results. Conflicts of interest with industry were identified in 33 studies, and in 17 studies, these conflicts were not declared in the appropriate section. Conclusion From a methodological perspective, studies on fortified infant formula display low quality, made evident by the high risk of bias. Additionally, there are frequent conflicts of interest. These aspects must be considered by health professionals and the population when drawing up recommendations for use of this product.