The etiology of cognitive impairment in diabetes is unknown, but probably associated with many factors. One of the recent hypotheses suggests that ghrelin could be involved in cognitive impairment in diabetic patients. It has been reported that ghrelin signaling occurs in the hippocampus and improves memory and spatial learning. The aim of this study was to evaluate serum levels of ghrelin in elderly, diabetic patients with and without mild cognitive impairment (MCI) and to determine the predictors of having MCI in elderly diabetics.
The cross-sectional study was conduct among 276 elderly subjects with type 2 diabetes. 87 patients with MCI and 189 controls were selected according to the criteria proposed by the MCI Working Group of the European Consortium on Alzheimer’s Disease (using the Montreal Cognitive Assessment: MoCA score). Data of biochemical parameters and biomarkers were collected. The serum levels of ghrelin were assessed using ELISA kit.
Serum levels of ghrelin were significantly lower in patients with MCI compared to controls. In MCI patients serum ghrelin levels were positively correlated with MoCA score and negatively correlated with HbA1c and BMI. The logistic regression models revealed that variables which increased the likelihood of diagnosis of MCI in elderly diabetic patients were: lower levels of ghrelin, higher levels of HbA1c, hypertension, previous cardiovascular disease, increased number of co-morbidities, and less years of formal education.
In summary, serum levels of ghrelin were decreased in MCI elderly diabetic patients compared to controls and associated with poor MoCA score. The results indicated that lower ghrelin levels may be a risk factor for a cognitive impairment in diabetic, elderly patients. Further prospective larger studies are needed to confirm the role of this marker in the progression to dementia.