The purpose of this study was to thoroughly assess cognitive disorders in diabetic elderly people. We concluded in our study population that diabetic patients were more vulnerable to cognitive impairment and that lower physical activity would increase the chances of diabetic patients living with cognitive impairment. It was discovered that hyperglycemia in diabetic patients predisposes them to cognitive impairment the most, and after adjustment of underlying factors such as age, gender, BMI, waist circumference, physical activity, and smoking, we estimated that the incidence of cognitive impairment in diabetic patients increases up to 1.48 times. Furthermore, characteristics such as advanced age, female gender, a positive history of hypertension, widowhood, elevated LDL-C, and even low MET energy expenditure can all be considered risk factors for cognitive impairment. Overall, given diabetics' susceptibility to cognitive impairment, it is reasonable to expect that better glycemic control can suspend the progression of cognitive impairment or even reverse it.
Our study's findings were consistent with those of previous studies. According to the study by Xue et al. , diabetes increased the risk of cognitive impairment by 1.25 to 1.91 times, also fasting glucose levels, HbA1C levels, and insulin resistance index had a significant linear relationship with the incidence and progression of dementia. A study by Gao et al.  propounded the duration from onset of diabetes as a risk factor for dementia among the diabetic population alongside other risk factors like higher levels of age, current smoking, mean waist circumference, duration of diabetes, insulin intake, systolic blood pressure, FBS, HgA1c, and, immunoreactive insulin (IRI). According to Tiwari et al. , cognitive impairment is expected to be 1.3 times more common in diabetics. As reported by Sun et al. age, education level, diabetes duration, FBS, and A1C levels all contribute to cognitive impairment in older T2DM. Another study by Jia et al. in China considered old age, female gender, low levels of education, widowhood or divorce, smoking history, hypertension, cardiovascular diseases, and ischemic brain diseases as the risk factors for dementia among patients with diabetes. They also illustrated that the prevalence of cognitive impairment increased in diabetics 2.14 times. Consequently, T2DM, especially in poorly controlled conditions, predisposes to disparate stages of cognitive impairment, and some of the conditions associated with diabetes seem to exacerbate that impairment . Several studies have been conducted about the pathophysiology and progression of cognitive impairment. Impaired insulin signaling and insulin receptor sensitivity in neurons and dendritic branches in Alzheimer‘s patients indicate a link between diabetes and cognitive impairment . The second related consequence is mitochondrial dysfunction. Insulin is essential for increasing mitochondrial activity in hippocampal synaptosomes . Cerebral mitochondrial function declines in AD patients, which has been linked to cortical hypometabolism and impaired insulin signaling in the brain. In this regard, the pattern of metabolic changes in AD patients has influenced mitochondrial bioenergetic inhibitors . Hence, mitochondrial functions after the metabolic regulations are affected by insulin, manipulating cognitive functions . The relationship between diabetic autonomic neuropathy and the incidence of cognitive impairment is a further considerable issue. It has been demonstrated that diabetic autonomic neuropathy is related intimately to hypertension and increased risk of cerebral stroke, both of which are associated with cognitive impairment. Neuroinflammation and brain changes are two other significant concerns raised regarding diabetic cognitive impairment. Accumulation of inflammatory cytokines in the brain has been confirmed in diabetics, which has a significant effect on neuronal damage . Moreover, NF-kb regulates oxygen radicals and the expression of TNF and variegated interleukins and therefore has an unassailable influence on initiating and activating the inflammatory cascade. High TNF levels and activity inhibit the insulin signaling pathway, which leads to increased production of oxygen radicals or ROS and the progression of cognitive impairment in these individuals [30–32].
According to Sundermann's findings, even prediabetes harms brain metabolism in older men and women. In light of previous findings linking T2DM to reduced brain volume and AD pathology[33–37], the findings of this study suggest that functional changes may occur before brain volume changes in the early stages of T2DM. This study also revealed that prediabetes was associated with poorer executive function overall and language performance specifically in the context of mean cognitive impairment (MCI) in women only. Despite this fact that even though these findings and the sex distribution contradict our findings. Dybjer et. al. discovered that pre-diabetes and newly diagnosed diabetes are linked to MCI, and that blood glucose levels, even at the upper end of the normal range, may have a marginally negative effect on cognition. As compared to a healthy individual with normal glucose tolerance, prediabetes or diabetes had slight negative effects on memory, processing speed, and executive functioning. Since there is no association between prediabetics and cognitive impairment, our findings contradict this article. This could be due to different thresholds for diagnosing prediabetic patients, sample size randomization, or the cognitive impairment assessment system. This should be investigated further in future studies on the matter.