RESUMEN
INTRODUCTION: Hair cortisol concentrations (HCC) have been found to be related to various common childhood diseases, like otitis media, conjunctivitis, respiratory viral infections, and asthma. However, the confounding effects of age, gender, body mass index (BMI), pubertal stage (Tanner stages), socioeconomic status (SES) as well as of some hair maintenance procedures on HCC are still not well examined. METHODS: A population-based cohort of 434 children aged between 5 and 18 years was examined for HCC between January 2012 and February 2015 in the context of the Leipzig Research Centre for Civilization Diseases (LIFE) Child study. Thereby, anthropometric data, gender, BMI, SES and pubertal status were assessed. HCC was measured by liquid chromatography mass spectrometry. RESULTS: In the total cohort, HCC levels ranged between 0.95 and 29.86 pg/mg. In prepuberty, boys showed significantly higher HCC than girls (6.54 vs. 3.73 pg/mg, p < 0.05). During puberty HCC values in both genders converged. Higher BMI was significantly associated with higher HCC in both genders. In girls, HCC did not differ depending on Tanner stages. In boys, HCC was significantly higher in Tanner stage 1 than in stages 2-5. CONCLUSION: Measuring cortisol concentration in hair gives information about long-term release of cortisol. We have found that puberty, gender, and BMI had a profound effect on HCC. As a result, further research should take into account the potentially confounding role of puberty, gender and BMI and may use the results of our study as a reference at determining values of HCC in healthy children.