Amino acid-based formula and Clostridioides difficile -associated disease in infants: concerns regarding causal interpretation

with formula feeding is a well-established finding. This distinction has important clinical implications, as AAF remains an essential nutritional intervention for children with appropriate indications, and in young children microbiological detection and microbiome alterations must be interpreted alongside age, clinical symptoms, underlying disease, dietary history, and other relevant exposures. An overly causal interpretation could create unnecessary concern among families and complicate clinical decision-making. To make these considerations operational, we specify the elements of a decisive prospective study, including a minimum event count of ~60 adjudicated CDAD cases, a blinded tiered diagnostic algorithm, and detailed AAF exposure ascertainment.