LAUSR

PurposeHypothyroidism is associated with an increase in serum cortisol level while the long-term activity of hypothalamic-pituitary-adrenal (HPA) axis in hypothyroid, and subclinical hypothyroid (SCH) subjects has not been studied. This study aimed to assess the hair cortisol levels as a long-term activity of HPA axis in hypothyroid, SCH and a group of healthy adult subjects. Also, it aimed to examine the correlation of hair cortisol levels with hypothalamic-pituitary-thyroid (HPT) axis and anthropometric measures.MethodsWe prospectively evaluated a group of normal, SCH and hypothyroid subjects. Serum TSH, FT4, and FT3 were measured as a component of the HPT axis. Hair samples were collected, prepared, followed by extraction of hair cortisol and measurement in pg/mg of hair. Hair cortisol levels were compared in normal, SCH and hypothyroid groups and correlated with HPT axis and anthropometric data.ResultsA total of 65 healthy volunteers were analyzed, and the mean hair cortisol level was reported to be 17.38 pg/mg of hair. Hair cortisol level was slightly higher in the SCH subjects, 18.19 pg/mg of hair; however the difference was not significant. Compared to the euthyroid subject, a significantly higher hair cortisol level was recorded in the hypothyroid subjects, 24.17 pg/mg hair, p < .05. Hair cortisol was significantly and positively associated with each of the serum TSH, age, weight and BMI (p < .05).ConclusionsOvert hypothyroidism but not SCH is significantly associated with higher hair cortisol levels compared to normal subjects, and a significant relation between hair cortisol with HPT axis was found. Also, weight and BMI were positively correlated with hair cortisol level.