Cortisol and Electrolyte Levels in Type 2 Diabetic Patients Attending a State University Teaching Hospital, Ogun State, Nigeria

Abstract

The involvement of the Hypothalamic - Pituitary – Adrenal (HPA) axis activity in type 2 diabetes mellitus has been investigated by some studies. While some reported an enhanced activity of the axis, others showed no alteration. Disturbances of electrolyte homeostasis in uncomplicated diabetes have been reported and it is a known fact through basic knowledge that abnormalities of HPA axis also affect electrolyte homeostasis. The majority of diabetic patients eat diets that are rich  in potassium (plantain, beans, etc ) and this also has implication on the electrolytes.

This study was designed to establish cortisol and electrolytes levels among uncomplicated type 2 diabetic patients attending a University Teaching Hospital to know whether there is enhanced HPA axis or not in these patients and look at the pattern of the overall consequences on their electrolyte status. A total of 110 volunteers were used, 60 diabetics and 50 non-diabetics (control). Body Mass Index (BMI) and blood pressures were measured and blood samples taken at 8:00am for fasting plasma cortisol, fasting plasma glucose and electrolytes. The samples were analyzed using standard methods.

Results indicate that there was a statistically significant difference (P < 0.05) between the mean values of Waist/Hip Ratio (WHR) of the Diabetics and control but no statistically significant difference (P > 0.05) observed between the mean values of the BMI of the Diabetics compared with the control. The mean cortisol levels of the Diabetics and the control showed no statistically significant difference (P > 0.05) even though a higher percentage of the diabetics have higher serum cortisol levels. However, there were statistically significant differences (P < 0.05) in the mean values of the fasting plasma glucose, sodium and potassium comparing the Diabetics with the control, indicating a significant increase in plasma glucose, decrease in plasma sodium and increase in plasma potassium, comparing the diabetics with the control respectively.

Although a higher percentage of the Diabetic population had higher serum cortisol levels  while a higher percentage of the control had lower levels, there was no significant correlation between the plasma  cortisol levels and either the plasma glucose levels or any of the other biochemical parameters in both the Diabetics and control. Similarly, no significant correlation between cortisol level and either the BMI or WHR. However, there was a significant negative correlation between sodium and potassium (γ =0.601, P<0.05).

The study showed that there was no alteration in the HPA axis activity of the type 2 DM subjects. Reduced sodium level and increased potassium level were observed in the Diabetics compared to the control subjects. This may be due to osmotic flux due to the hyperglycaemia in the diabetics or the effect of the peculiar diet they eat or both. It may even be the effect of medication. Studies to elucidate further on the electrolyte patterns in DM is advised and diabetics are also implored to be aware of possible electrolyte disturbances that may result from these factors.

Key words: Cortisol, Electrolytes, Type 2 Diabetic Patients, University Teaching Hospital