Directions of Longitudinal Relationships between Housing-related Control Beliefs and Activities of Daily Living among People with Parkinson's disease.

Introduction: The gerontological literature suggests that external housing-related control beliefs (HCB) influence activities of daily living (ADL) among older people, but knowledge is scarce for people with Parkinson's disease (PD). This longitudinal study aimed to explore the directions of the relationship between external HCB and ADL among people with PD.

Methods: Baseline (T1) and 3-year follow-up data (T2) were collected from 154 people with PD (mean age = 68 years, T1). Two regression analyses were applied, where dependent (T2 values) and independent (T1 values) variables-external HCB score and PD specific ADL (PADLS)-were switched, adjusting for age, disease severity, cognitive functioning, and accessibility problems.

Results: There was a significant effect of ADL on external HCB (β = 3.07, p < .001, CI [1.28, 4.85]), but no effect in the reverse direction. The proportion with moderate-extreme ADL difficulties increased over time (from 20.8% to 32.5%, p = .006).

Discussion: ADL difficulties seem to lead to higher external HCB, but not the other way around, which contradicts assumptions in environmental gerontology theories. This new knowledge can promote theory development. While additional studies are required to verify whether this is a disease-specific finding, this indicates the importance of targeting ADL if the purpose is to influence external HCB among people with PD.