RETRACTED: The correlation of serum adiponectin and insulin resistance with the presence and severity of dementia in non-obese Alzheimer's patients

Abstract

Alteration in the insulin signaling could contribute to the development of Alzheimer's disease (AD) through metabolic or inflammatory processes, adipokines could affect insulin dysregulation. This study aimed to investigate whether there is a correlation between serum adiponectin level alteration and insulin resistance with the presence and severity of AD, compared to normal controls. This analytical observational study was conducted on 60 non-overweight and non-diabetic participants who were assigned to AD patients (n=34) and healthy volunteers (n=26). The diagnosis and severity of dementia were evaluated by the same protocol, and the Mini-Mental Score Exam (MMSE) questionnaire was utilized to collect the data. Moreover, adiponectin concentration, fasting blood sugar, and plasma insulin levels were measured using enzyme-linked immunosorbent assay. Furthermore, the homeostasis model assessment for insulin resistance (HOMA-IR) was utilized in this study. The mean ages of the AD patients and control participants were 71.35 and 70.46, respectively. In addition, the mean values of the serum adiponectin level of the participants were 9660 and 12,730ng/mL in control and AD groups, respectively (P≤0.05). Additionally, the insulin resistance (IR) was 2.90 and 5.10 in the control and AD groups, respectively (P≤0.05). According to the results, there was a significant positive correlation between serum adiponectin level and HOMA-IR in the AD group; however, no significant correlation was observed between serum adiponectin level and MMSE score in this group. The MMSE score of AD patients significantly decreased by 1.2 times with an increase in each score of the IR (P≤0.05). A significant direct positive correlation was observed between the serum adiponectin level and IR among the AD patients. However, a significant decrease in cognition levels was detected following an increase in IR scores of the AD patients.