Hydrocortisone dosage at 3 years of age is positively correlated with body mass index at 10 years in individuals with 21-hydroxylase deficiency

Obesity is a major complication in individuals with 21-hydroxylase deficiency (21-OHD) and excessive hydrocortisone (HC) dosing is a likely contributing factor. However, the association between the HC dosage and body mass index (BMI) during childhood remains unclear. We previously reported a positive correlation between HC dosage during late infancy and a subsequent increase in BMI. In this study, we expanded our research to assess the impact of HC dosage during childhood. We retrospectively collected data on HC dosages and BMI in 28 patients with 21-OHD (9 boys and 19 girls) at both 3 and 10 yr of age and conducted correlation analyses between HC dosage and BMI. No significant cross-sectional associations were observed between the body-surface-area adjusted HC dosage (HC/BSA) and BMI standard deviation score (BMI-SDS) at either 3 or 10 yr of age. However, the HC/BSA at 3 yr positively correlated with the BMI-SDS at 10 yr, indicating a longitudinal relationship. Furthermore, children whose HC/BSA at 3 yr fell almost within the guideline-recommended range exhibited significantly lower BMI-SDS at 10 yr compared to those receiving higher doses. The longitudinal association between HC dosage and BMI suggests the importance of careful HC dose monitoring, although causality could not be established.