Children with asthma have significantly lower long-term cortisol levels in their scalp hair than healthy children

Aim: Noninvasive measurement of long-term cortisol levels is a useful way of evaluating the effect of chronic disease on the hypothalamic-pituitary-adrenal axis in children. The aim of this pilot study was to compare hair cortisol levels in children using inhaled corticosteroids for asthma and healthy children and to determine the association with short-term salivary cortisol levels. Methods: Cortisol levels were measured in the scalp hair and saliva of prepubertal children with asthma (n = 10) and without asthma (n = 10). Asthma control was assessed using an asthma questionnaire and pulmonary function tests. Results: The median (95% CI) cortisol level in the scalp hair of the children with asthma (2.0 pg/mg; 1.4-4.1) was significantly lower than the healthy children (4.3 pg/mg; 1.8-5.9). Morning salivary cortisol levels were significantly lower for the children with asthma (5.9 nmol/L; 3.2-11.1) than the healthy children (9.0 nmol/L; 4.4-31.6). There was no significant association between cortisol levels in hair and saliva. Conclusion: Long-term cortisol levels were significantly lower in children with asthma than healthy children. Measuring long-term cortisol levels in scalp hair is an attractive, noninvasive tool that can evaluate the effect of asthma and its treatment on the hypothalamic-pituitary-adrenal axis.