Sex-related differences in the association of salivary cortisol levels and type 2 diabetes. Findings from the cross-sectional population based KORA-Age study.

BACKGROUND: Dysregulation in the cortisol secretion may have a role in the development of type 2 diabetes although conflicting evidence on the particular cortisol secretion patterns and type 2 diabetes demands further investigations. We aim to examine the association of cortisol levels and diurnal secretion patterns with prevalence of type 2 diabetes and HbA1c levels as well as the potential impact of sex and adiposity on this association. METHODS: A cross-sectional analysis was conducted among 757 participants (aged 65-90 years) of the population-based KORA (Cooperative Health Research in the Region of Augsburg)-Age study. Multivariate regression analyses were employed to examine the association between salivary cortisol (measured upon waking (M1), 30min after awakening (M2), and in the late night (LNSC)) and type 2 diabetes as well as glycated hemoglobin (HbA1c) with adjustments for potential confounders. RESULTS: In the total sample population, an elevated LNSC level was observed in type 2 diabetes patients compared to non-patients (P=0.04). In sex-stratified analyses, diabetic men showed a greater Cortisol Awakening Response (CAR) (P=0.02). Diabetic women had significantly elevated LNSC levels (P=0.04). HbA1c was positively associated with both CAR and LNSC levels but was negatively associated with M1 to LNSC ratio. CONCLUSION: In this aged population, type 2 diabetes is associated with dysregulated cortisol secretion characterized by distinct sex specific diurnal patterns