Assessment of baseline adrenal function by measurement of long term cortisol levels in scalp hair of asthmatic children using inhaled corticosteroids compared to healthy controls

Abstract

Inhalation corticosteroids (ICS) usage for asthma can interfere with the hypothalamic-pituitary-adrenal axis. Cortisol levels measured in scalp hair provide a marker for long-term cortisol exposure and seems promising for diagnosing hypercortisolism. The aim of this study is to determine the long-term hair cortisol concentrations (HCC) in children with asthma and ICS usage compared to healthy controls. A case-control study was conducted at the Groene Hart Hospital, Gouda, 2014. Eligible as cases were asthmatic children (4-18 years) using ICS for more than three months. Healthy controls were voluntarily enrolled children from schools or from healthy siblings attending the pediatric outpatient clinic at Erasmus MC, Rotterdam. HCC in scalp hair was analyzed by Liquid chromotography-tandem mass spectrometry. 80 cases and 258 controls were enrolled for analysis. The use of budesonide equivalent by cases was 200-1200 µg/day with a mean of 17.26 µg/kg (95%CI 6.03 – 54.55) per day. Mean HCC-levels did not differ between cases and controls (p = 0.94) even after adjusting for age, gender, height-SDS, and BMI-SDS (p = 0.81). No correlation was found between the Budesonide doses and HCC levels. Assessment of long-term cortisol levels by hair cortisol showed no difference in baseline adrenal function in children with asthma and ICS to their healthy controls. This study suggests that the HPA-axis dysfunction, found in adrenal stimulation tests in children with asthma on ICS may not lead to clinical relevant HPA-axis changes in day-to-day life.