Longitudinal Assessment of Cognitive Decline, Cerebrovascular Pathology, and Alzheimer’s Disease Biomarkers in Elderly Individuals with Type 2 Diabetes Mellitus and Metabolic Syndrome

Pooja Menon, Dr. Sandeep Rao

Department of Geriatric Medicine and Translational Neuroscience, Madras Medical College (MMC)

1. Abstract

Type 2 diabetes mellitus (T2DM) and metabolic syndrome (MetS) are increasingly acknowledged as significant factors in the development of neurodegenerative diseases, cognitive decline, and cerebrovascular issues among the elderly. The worldwide increase in dementia cases, especially Alzheimer’s disease (AD), is occurring alongside the rising prevalence of T2DM and MetS, indicating common underlying mechanisms such as insulin resistance, vascular damage, chronic inflammation, oxidative stress, and disruptions in amyloid metabolism. Longitudinal research shows that those with T2DM and MetS experience faster cognitive deterioration, a higher likelihood of mild cognitive impairment (MCI), and a greater chance of progressing to dementia. Additionally, studies using neuroimaging and biomarkers have found links between blood sugar irregularities, tau pathology, neurodegeneration, and cerebrovascular issues, highlighting the necessity for comprehensive assessment models. This detailed research article offers a longitudinal framework for examining cognitive changes, cerebrovascular modifications, and AD-related biomarkers in older adults with T2DM and MetS. The review compiles evidence from epidemiological research, neuroimaging results, and molecular biomarker studies to clarify the pathophysiological connections between metabolic dysfunction and neurodegeneration. It also proposes a methodological strategy for longitudinal cohort evaluations that include cognitive assessments, neuroimaging techniques, and circulating biomarkers. The findings indicate that early metabolic issues predict worsening executive function, memory, and processing speed, along with structural brain changes like hippocampal shrinkage, white matter lesions, and decreased gray matter volume. Evidence also suggests that T2DM has a stronger link to neurodegeneration and tau pathology than to amyloid buildup. The article concludes that the combination of metabolic and cerebrovascular pathology speeds up AD-related cognitive decline in older populations. Early detection using integrated biomarker panels and ongoing monitoring could enhance risk assessment, enable targeted treatments, and lessen the future impact of dementia. The study emphasizes the need for multidisciplinary approaches that combine endocrinology, neurology, and geriatric medicine to tackle neurodegeneration driven by metabolic factors.

2. Keywords

Type 2 diabetes mellitus; metabolic syndrome; cognitive deterioration; Alzheimer’s disease; cerebrovascular pathology; long-term study; biomarkers; neurodegeneration; mild cognitive impairment; insulin resistance; dementia risk.