Obesity in children with congenital adrenal hyperplasia in the Minnesota cohort: importance of adjusting body mass index for height-age.

Objectives: To evaluate obesity and overweight in children with congenital adrenal hyperplasia (CAH) and associations with glucocorticoids, fludrocortisone and disease control. Adjusting body mass index-for-height-age (BMI ) percentile is proposed to correct misclassification of obese/overweight status in CAH children with advanced bone age and tall-for-age stature.

Design: Longitudinal.

Patients: One hundred and ninety-four children with CAH seen from 1970 to 2013: 124 salt wasting (SW); 70 simple virilizing (SV); 102 females.

Measurements: Body mass index (BMI) end-points were overweight (85-94 percentile) and obese (≥95 percentile).

Results: Approximately 50% of the children had at least one BMI measurement ≥95 percentile and about 70% had at least one ≥85 percentile. Using BMI percentiles, obesity incidence decreased slightly in SW children (47-43%) and markedly in SV children (50-33%); however, overweight status was not reduced. Only 6% of SW and 1% of SV children were persistently obese (≥3 clinic visits) when BMI was applied, whereas overweight status persisted in 35% of SW and 33% of SV children. Most obesity or overweight when using BMI occurred before age 10 and there was no association with hydrocortisone (HC) or fludrocortisone dosing. Adiposity rebound for SW children occurred by 3·3 years and in SV females by age 3·8 years, over a year earlier than the adiposity rebound for healthy children.

Conclusion: Children with CAH are at higher risk for early onset obesity and overweight with or without using BMI but rates of persistent obesity were lower than previously reported. Careful HC dosing during early childhood is needed to prevent increased weight gain and an early adiposity rebound.