Association of Insulin Resistance and Metabolic Syndrome with Cognitive Impairment in Nonobese, Nondiabetic Older Adults: A Cross-Sectional Study

Background/Objectives: Insulin resistance (IR) and metabolic Syndrome (MSy) have been linked to cognitive decline, but their presence in mild cognitive impairment (MCI) and Alzheimer disease (AD) remains unclear. We evaluated MSy and IR in nonobese, nondiabetic older adults with cognitive dysfunction.

Methods

The cross-sectional study included 143 participants aged 65–90 years: 62 with AD, 41 with MCI, and 40 cognitively preserved controls. Anthropometric measures, blood pressure, fasting glucose, insulin, and lipid levels were assessed. Diabetes was excluded by oral glucose tolerance testing. IR was estimated using HOMA-IR, and MSy was diagnosed according to International Diabetes Federation (IDF) criteria. Group differences and associations with cognitive impairment were assessed using analysis of variance and regression analyses.