Worker functions and traits associated with occupations and the development of AD

Objective: To investigate the association between Alzheimer disease (AD) and worker functions and traits associated with occupations. Background: Studies have reported that occupational attainment is related to AD. However, most have not identified specific worker functions and traits (i.e., occupational demands) of occupations that may explain the association, nor have they accounted for changing occupational demands over time. Methods: Within- and between-group differences in mental, motor, physical, and social occupational demands of 122 AD cases and 235 control subjects were compared across four decades of life (20s, 30s, 40s, and 50s) using repeated-measures analyses of covariance adjusted for race, gender, year of birth, and education. Results: Overall, mental occupational demands were significantly lower and physical occupational demands were significantly higher for cases than for control subjects. Case/control differences in mental demand scores were not found in their 20s but only in later decades. Differences in physical demands were found in all decades but their 30s. Social and motor demands did not differ between cases and control subjects. Among cases only, there were no significant occupational demand score differences across decades. In contrast, mental and social demand scores of control subjects increased in later decades, and motor demand scores declined. Like cases, physical demand scores of control subjects remained stable across the decades. Conclusions: The authors' results may indicate a relatively early influence of Alzheimer disease neuropathology on capacity to pursue mentally demanding occupations. However, results also are consistent with the notion that mentally demanding occupations have a direct influence on Alzheimer disease neuropathology.