Insulin resistance and executive dysfunction in older persons.

Area of Science:

• Neuroscience
• Metabolic Health
• Gerontology

Background:

• Insulin resistance (IR) is a metabolic condition characterized by decreased sensitivity to insulin.
• Executive functions are complex cognitive processes crucial for goal-directed behavior.
• Cognitive decline in aging is a significant public health concern, particularly in individuals without diagnosed diabetes or dementia.

Purpose of the Study:

• To investigate the association between insulin resistance (IR) and executive dysfunction.
• To assess this relationship in a large, population-based cohort of older individuals without diabetes mellitus (DM) or dementia.

Main Methods:

• A cross-sectional study involving 597 participants aged 65-93 years.
• Assessment of IR using the homeostasis model assessment (HOMA).
• Evaluation of executive function via the Trail Making Test (TMT) A and B, and the Mini-Mental State Examination (MMSE).

Main Results:

• Insulin resistance (IR) was significantly associated with poorer performance on executive function tests (TMT-A, TMT-B, and DIFF B-A).
• These associations remained significant after adjusting for various demographic, metabolic, and lifestyle factors.
• IR emerged as an independent determinant of executive dysfunction, even after accounting for cognitive status (MMSE).

Conclusions:

• Insulin resistance (IR) is independently associated with impaired frontal cortex function in older adults.
• Executive dysfunction, as measured by TMT performance, is linked to IR in this non-diabetic, non-demented population.
• These findings suggest that metabolic health plays a critical role in maintaining cognitive function during aging.