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Author ORCID Identifier

 orcid.org/0009-0004-4552-6716  

Date Available

4-30-2028

Year of Publication

2026

Document Type

Graduate Capstone Project

Degree Name

Master of Public Health (M.P.H.)

College

Public Health

Department/School/Program

Public Health

Faculty

Dr. Erin Abner

Committee Member

Dr. Steven Browning

Faculty

Dr. Jay Christian

Abstract

Introduction: Dementia is a growing public health concern, with functional decline serving as a key indicator of disease progression. Occupational complexity has been proposed as a marker of cognitive reserve, which may delay the onset of cognitive impairment. However, its relationship with functional ability across stages of cognitive decline remains unclear. This study examined the association between lifetime occupational complexity and functional ability among older Kentucky adults.

Methods: This cross-sectional study used data from 350 participants in the University of Kentucky Alzheimer’s Disease Research Center (UK-ADRC) cohort. Occupational complexity was categorized as low, medium, or high using the Hollingshead classification system. Functional ability was measured using the Functional Activities Scale (FAS), and cognitive status was defined using the Clinical Dementia Rating (CDR) scale (normal, mild cognitive impairment, dementia). Multivariable linear regression models stratified by cognitive status were used to estimate associations, adjusting for demographic and clinical covariates. Sensitivity analyses included social determinants of health.

Results: Occupational complexity was not significantly associated with functional ability in either unadjusted or adjusted analyses. In contrast, cognitive status was strongly associated with functional impairment, with FAS scores increasing substantially from normal cognition to MCI and dementia. These findings remained consistent after adjusting for social variables. Additional analyses showed minimal differences in functional ability across occupational groups within each cognitive status category.

Discussion: These findings suggest that occupational complexity does not independently influence functional ability once cognitive impairment is present. While occupational complexity may contribute to cognitive reserve and delay the onset of cognitive decline, functional decline appears to be driven more by disease progression and clinical factors. Public health efforts should emphasize early-life and midlife interventions to promote cognitive health, as well as strategies to maintain functional independence among individuals with cognitive impairment.

Funding Information

This work was supported by a traineeship from the National Institute for Occupational Safety and Health (NIOSH) through the Central Appalachian Regional Education and Research Center (CARERC) Occupational Epidemiology Training Program, which provided financial support to the author during the completion of this project (2025-2026). 

Available for download on Sunday, April 30, 2028

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