Comparison of Salivary Cortisol, Serum Cortisol, Plasma ACTH and Urinary Free Cortisol Levels in Thyrotoxic and Hypothyroid Patients

Abstract

Objective: Hypothalamo-pituitary-adrenal (HPA) axis is affected by thyroid hormones. The present study was designed to compare the level of salivary cortisol, serum cortisol, plasma adrenocorticotropic hormone (ACTH) and urinary free cortisol (UFC) levels in patients with subclinical and overt thyrotoxicosis and hypothyroidism. Material and Methods: We analyzed the salivary cortisol, serum cortisol, plasma ACTH and UFC levels in 123 patients with thyroid dysfunction. The patients were classified into four groups; overt thyrotoxicosis (n=32), subclinical thyrotoxicosis (n=29), overt hypothyroidism (n=28) and subclinical hypothyroidism (n=34). Results: There were no significant differences in terms of salivary cortisol, serum cortisol, plasma ACTH and UFC levels in patients with subclinical and overt thyrotcodcosis (p>0.05). Similarly, no significant differences could be detected in terms of salivary cortisol, serum cortisol, plasma ACTH and UFC levels in patients with subclinical and overt hypothyroidism (p>0.05). The comparison of patients with hypothyroidism and thyrotoxicosis also did not yield any significant difference in terms of salivary cortisol, serum conisol, plasma ACTH and UFC levels (p>0.05). Conclusion: Similar salivary cortisol, serum cortisol, plasma ACTH and UFC levels were detected in patients with hypothyroidism and thyrotoxicosis. Thus, we may suggest that thyroid hormone status does not play a role in the HPA axis. The major limitation of this study was the absence of a healthy control group. Further studies with large numbers of patients are required to clarify the association between thyroid hormone dysfunction and glucocorticoid levels.