Aging
Associations of shift work with longitudinal cognitive decline among a diverse cohort of older adults: The KHANDLE study Hilary L. Colbeth* Hilary Colbeth Colbeth Colbeth Colbeth Colbeth Colbeth Department of Public Health Sciences, University of California, Davis
Background: Studies on the impacts of work patterns on cognitive decline are scarce due to challenges collecting exposure and repeated late-life cognitive data over decades; few investigated shift work with cognitive change.
Methods: We included 1,643 Kaiser Health Aging and Different Life Experiences (KHANDLE) study participants. Using the American Time Use Survey, we determined if participant’s self-reported main lifetime occupation was characterized by night shifts (23:00–6:00), long hours (≥8hr days), or included weekends. Executive function (EF) and verbal episodic memory (VM) were measured using the Spanish and English Neuropsychological Scales across up to 4 interview waves and z-scored to baseline. To test associations of long hours, nights, or weekend work, respectively, and cognitive change, we fit joint models that use linear mixed effects and Cox proportional hazards sub-models to account for the competing risk of death. Time to all-cause mortality was calculated from baseline to death.
Results: Participants (mean age=75 years SD:6.71[range:65-90]; 59% female; 51% ≤some college) were 25% Asian, 26% Black, 20% Latinx, and 29% White; 43% worked long hours, 42% night shifts, and 20% weekends. During a mean follow-up of 3.98 years (SD:1.82[0-7.65]), 14% died. In joint models, shift work (nights and weekends, respectively) and long hours were associated with lower EF and VM scores at baseline compared to standard schedules (Figure 1). Night work and long hours were not associated with rates of decline for EF and VM. However, weekend work was associated with faster decline in EF and VM (both β:-0.02, 95% CI:-0.04,-0.00).
Conclusions: Within an ethnoracially diverse cohort, shift work and long hours were associated with lower baseline cognition and weekend work was associated with slightly faster decline than weekday shifts only. Further research will examine industry-specific impacts of work patterns on cognitive function.
