Cortisol Correlates with Structural Magnetic Resonance Imaging Parameters in Middle Aged Bulgarian Patients with Metabolic Syndrome: A Pilot Study

BACKGROUND: There is a dose-dependent relationship between chronically increased cortisol levels and the number of metabolic syndrome (MetS) components. Both cortisol and MetS are linked to various brain abnormalities. AIM: To investigate an association of MetS components and salivary cortisol levels with cortical thickness in middle-aged Bulgarian patients with MetS. MATERIALS AND METHODS: We examined 26 healthy volunteers (mean age 50, 16±3.1 yrs) divided into two groups depending on whether or not they were diagnosed with MetS. Salivary cortisol was sampled and tested at two time points -morning and evening. Cortical thickness measures were obtained from structural T1-images using FreeSurfer software. We performed vertex-wise analysis across entire cortex and for preselected brain regions in frontal, temporal and cingulate cortex partial correlation analysis, accounting for gender. RESULTS: The control group consisted of 12 women; in the MetS group there were 6 men and 8 women. The whole brain analysis showed that waist circumference (WC) was negatively correlated with cortical thickness in rostro-lateral area in left frontal lobe and the right lateral orbito-frontal cortex. Morning cortisol levels, accounting for sex and WC, correlated negatively with thickness in left superior temporal area (r = -0.477, p = 0.039) and entorhinal area (r = -0.465, p = 0.045) and left mediotemporal cortex (r = -0.477, p = 0.038). CONCLUSION: Our pilot study confirmed that WC is associated with brain atrophic changes mainly in the frontal lobe. Our finding that cortisol levels negatively correlate with thinning of the cortex in temporal lobe should be further explored in subsequent study.