Does vitamin D deficiency predispose to allergic proctocolitis?

Objectives: Awareness of vitamin D (vit D) deficiency or insufficiency has increased alongside the rising prevalence of allergic diseases worldwide. We aimed to evaluate vit D levels in infants with allergic proctocolitis (AP) to explore a possible relationship between AP and vit D status.

Methods: This prospective, observational, case-control study was conducted between January 2020 and December 2023, including infants aged 6 months and younger diagnosed with AP (AP group) and healthy infants of the same age (control group). Vit D levels in AP patients at the time of diagnosis were compared with those of healthy infants.

Results: A total of 116 patients (72 AP, 44 control) were included in the study. Statistically significant differences were found in vit D levels, eosinophil count, and eosinophil percentage between the groups. Vit D was deficient or insufficient in 34.7% of AP patients. Vit D levels were significantly lower in infants with AP, and the risk of developing AP was 3.5 times higher in infants whose vit D levels were below 40.75 mcg/L.

Conclusions: Our finding that vit D levels are lower in infants with AP compared to healthy infants may support an association between AP and vit D deficiency. This could also provide insight into the increasing prevalence of AP linked to environmental factors. We recommend that vit D levels be assessed in infants with AP at the time of diagnosis.