Type 2 diabetes mellitus (T2DM) has become one of the most difficult chronic non-communicable diseases in recent years, spreading around the world and being acknowledged as a major problem for healthcare systems everywhere (Pradeepa and Mohan, 2021; Dai et al., 2016). Aging is still seen as one of the primary risk factors for the development of T2DM, even though the disease can be seen at any age (Suastika et al., 2012; Zhao et al., 2022). in a way that affects over half of the elderly (those over 65) who have T2DM (Organization, 2018). The number of older people with T2DM is predicted to rise from 122 million to 253 million between 2017 and 2045(Bellary et al., 2021; Wei et al., 2024).

In the elderly, diabetes causes a high rate of morbidity and mortality. The age-standardized death rate for people with diabetes was expected to reach 1.5 million years based on the Global burden disease (GBD) statistics from 2021. Additionally, it was noted that over 66 million people suffer from years of life adjusted for disability because of T2DM. In the sense that T2DM is acknowledged as one of the primary causes of living with a handicap in people 70 years of age and older (Yang et al., 2024), as well as a contributing factor to the development of long-term effects such as mild cognitive impairment (MCI), physical disabilities, and frailty (Maltese et al., 2024; Luo et al., 2019).

The aged population has a much-increased risk of MCI due to the rising frequency of T2DM. According to epidemiological studies, people with T2DM have a 1.5–2.5 times higher relative risk of dementia, Alzheimer's disease, and vascular dementia than people without the disease (Alshaikh et al., 2021; Zhang et al., 2024). Furthermore, there are several of evidence that suggest that individuals with diabetes have a higher prevalence of MCI. A clinical condition known as MCI, which occurs between normal aging and dementia, is defined by impairment in memory and other cognitive functions in older adults. In 2021, a systematic review and meta-analysis study found that 44.3 % of diabetic individuals 60 years of age and older had MCI (You et al., 2021). Another study indicates that older adults with diabetes had an odds ratio (OR) of 1.468 times higher for MCI than older adults without T2DM (Zheng et al., 2023).

Although the effects of diabetes on the peripheral nervous system are well-established, the impact of this disease on the central nervous system remains unclear(Luchsinger, 2012). T2DM is associated with the acceleration and exacerbation of cognitive impairments in the elderly, encompassing severe conditions such as Alzheimer's disease and vascular dementia. Patients with both acute and chronic hyperglycemia live under a constant state of oxidative stress, which contributes to the complications of advanced stages of the disease(Hazari et al., 2015; Ma et al., 2023b).

Oxidative stress, inflammation, and vascular disorder linked to hyperglycemia and diabetes can all contribute significantly to MCI in diabetic individuals (Si et al., 2023; Casagrande et al., 2021). The occurrence of MCI is also influenced by lifestyle variables like poor food and physical inactivity, as well as demographic factors like age, the length of diabetes, the existence of comorbid illnesses like hypertension, and others. However, nothing is now known about the process underlying MCI in diabetic patients(Sherman et al., 2017).

Even while our knowledge of the connection between T2DM and MCI is expanding, a thorough synthesis of the available data is still required to pinpoint the key risk factors. In order to investigate the body of research on risk variables linked to MCI in older persons with T2DM, this study is a systematic review and meta-analysis.