Prenatal and postnatal risk factors associated with Kawasaki disease up to 3 years of age.

Kawasaki disease (KD) is an acute systemic vasculitis that is prevalent in infants and young children. We have previously reported associations between insufficient maternal folic acid supplementation and lower serum folic acid concentrations, maternal thyroid disease during pregnancy, and the presence of siblings with KD onset before 12 months. The etiology of KD remains poorly understood, with potentially age-dependent risk factors. We investigated associations between prenatal and postnatal exposure and KD onset between 12 and 36 months using data from the Japan Environment and Children's Study. Among 82,148 children, 686 developed KD. Logistic regression identified the following significant risk factors: maternal history of KD (adjusted odds ratio, 3.53 [95% confidence interval, 1.81-6.90]), maternal allergic disease (1.22 [1.02-1.44]), household income ≥ ¥4 million (1.21 [1.01-1.46]), male sex (1.19 [1.01-1.41]), presence of siblings (1.29 [1.07-1.54]), feeding commercial baby foods (1.35 [1.11-1.65]), yogurt consumption (1.38 [1.13-1.69]), and respiratory infections during infancy (1.21 [1.01-1.44]). In contrast, early wheat introduction was associated with a lower risk of KD (0.79 [0.65-0.97]). Prenatal factors previously associated with KD onset before 12 months were not significant in this age group. These findings suggest an age-dependent aspect and the involvement of infant nutrition and infectious exposure in the mechanisms of KD.