Relationship Between Occupational Complexity and Dementia Risk in Late-Life: A Population Study

According to cognitive reserve theory, challenging and/or stimulating cognitive activities can build a theoretical reserve, which may lead to a delay in the clinical expression of dementia and/or Alzheimer\u27s disease. These cognitively stimulating activities are thought to build cognitive strategies and neural pathways that are more efficient, enabling the individual to live symptom-free for a longer period of time. One mechanism through which cognitive reserve can be built is by participating in an occupation high in cognitive complexity. When individuals hold an occupation that is high in complexity, they may build their cognitive reserve in such a manner as to reduce their risk for dementia in late life. Using extant data from an existing longitudinal, population-based study, we examined the effect of various subdomains of cognitive complexity of the longest-held job on dementia risk. In Cox regression models, individuals holding agricultural occupations and occupations high in complexity of interaction with machinery, equipment, tools and inanimate objects ( things ) had an increased risk for both AD and dementia. Socioeconomic status was found to partially mediate the relationship between high things complexity and dementia/AD risk, as well as the relationship between agricultural occupations and dementia/AD risk. While there has been some debate regarding whether results reflect a true effect of occupational complexity or simply an effect of education, results from this study indicate that both occupational complexity and education contribute unique effects to dementia/AD risk. Gender, job duration, and APOE genotype were not found to moderate any of the above associations. An understanding of how occupational complexity impacts cognitive reserve and risk for dementia/AD will enable individuals as well as clinicians to implement activities that enhance cognitive reserve and lead to a greater number of years lived symptom-free from dementia/AD