Serum and Salivary Cortisol Levels in Diabetics Attending University of Calabar Teaching Hospital, Calabar, Nigeria

Aims: To investigate if salivary cortisol can be used as an alternative to serum cortisol in the management of diabetes mellitus.

Study design: The design of the study was cross sectional.

Place and Duration of Study: Diabetic Clinic of the Department of Internal Medicine and the Department of Chemical Pathology, University of Calabar Teaching Hospital between June 2009 and July 2010.

Methodology: Fifty five (55) type II diabetic patients and thirty three (33) non-diabetic controls (45 men, 43 women; age range 30 - 69 years) were recruited for this study. The levels of salivary cortisol, serum cortisol, fasting plasma glucose and glycated haemoglobin were determined. Serum and salivary cortisol was determined using enzyme immunoassay; fasting plasma glucose using colorimetric method and glycated haemoglobin using cation-exchange resin separation method.

Results: The mean serum and salivary cortisol levels were significantly higher (p=0.000) in diabetics as compared to the controls. The salivary cortisol was about 70% lower than the serum cortisol in each group. There was no significant difference between the percentage difference between the serum and salivary cortisol levels in both the diabetics and controls. There was a significant positive correlation between serum cortisol and salivary cortisol in both the diabetic subjects (r = 0.362, p=0.007) and controls (r =0.406, p= 0.019).

Conclusion: Cortisol levels in saliva reflected those in serum in both diabetics and controls therefore salivary cortisol may be used in place of serum cortisol in the management of diabetes.