Clinical characteristics and serum 25-hydroxyvitamin D levels in children with febrile seizures in China

The aim of this study was to evaluate the serum level of 25-hydroxyvitamin D (25(OH)D) in children with febrile seizures (FS) in Luzhou, Sichuan Province, China, and in particular its association with gender and age. This should inform possible strategies for supplementation with vitamin D, and hence for prevention of FS in the local pediatric population. The Febrile seizures group consisted of 747 children hospitalized with FS at the Southwest Medical University Affiliated Hospital from January 2020 to January 2024. The healthy control group was comprised of 750 children aged from 0 to 8 years who underwent health checkups during this period. The serum 25(OH)D level was analyzed in relation to gender and age to explore its association with FS. The median serum vitamin D level in the FS group (28.8 ng/mL; IQR 21.64, 33.64) was significantly lower than in the healthy control group (37.51 ng/mL; IQR 31.05, 37.51). The incidence of vitamin D deficiency in the FS group was 10.8%, which was significantly higher than in the healthy control group (P < 0.05). In addition, the serum vitamin D level in children with FS varied in different age groups, with significantly lower levels observed in older children (P < 0.05). ROC curve analysis revealed that a serum vitamin D level of 35.28 ng/mL showed 60.0% sensitivity and 84.7% specificity for predicting FS (P < 0.05). In this study cohort, the serum vitamin D level in children with FS was at the lower limit of the physiological range, and significantly lower than in healthy children. Furthermore, this level decreased with age in children with FS. Regular supplementation with vitamin D for 6 months after birth and outdoor sun exposure for more than 2 h per day can improve the serum vitamin D level in children with FS.