A recent study led by the Columbia University Mailman School of Public Health, the Columbia Aging Center, and the Norwegian Institute of Public Health sheds light on the potential safeguarding effect of engaging in cognitively stimulating occupations during midlife against the onset of mild cognitive impairment (MCI) and dementia in later years. This groundbreaking study, featured in Neurology, marks a significant departure from previous research by employing objective assessments rather than subjective evaluations to elucidate the correlation between occupational complexity and cognitive health outcomes.

The study, spearheaded by Vegard Skirbekk, PhD, professor of Epidemiology at Columbia Mailman School of Public Health and Columbia Aging Center, underscores the pivotal role of mentally challenging job tasks in preserving cognitive functioning throughout the ageing process. Trine Holt Edwin, the study’s first author from Oslo University Hospital, emphasises the critical importance of education and intellectually demanding professional environments in emphasising cognitive well-being in older individuals.

With a meticulous approach, the researchers leveraged data from the Norwegian administrative registry and occupational attributes sourced from the Occupational Information Network (O*NET) database. They examined over 300 occupations to gauge their cognitive demands across different stages of adulthood. The Routine Task Intensity (RTI) index, a proxy for occupational cognitive demands, was used, with lower RTI values indicative of more cognitively taxing job roles. By employing group-based trajectory modelling, the study identified distinct trajectories of occupational cognitive demands spanning participants’ occupational histories from their 30s through their 60s.

Subsequently, the researchers delved into the association between these trajectory groups and the incidence of clinically diagnosed MCI and dementia among participants in the HUNT4 70+ Study (2017-19). The analysis adjusted for various dementia risk factors, including age, gender, educational attainment, income, overall health status, and lifestyle habits.

The findings revealed a compelling inverse relationship between occupational cognitive demands and the risk of dementia in later life, even after accounting for potential confounders such as age, sex, and education. Specifically, individuals engaged in occupations characterised by high cognitive demands exhibited a significantly lower risk of dementia compared to those characterised in less cognitively demanding roles.

Trine Holt Edwin underscores the nuanced interplay between education and occupational complexity in influencing the risk of MCI and dementia, suggesting that both factors independently contribute to cognitive health outcomes. Yaakov Stern, the project’s principal investigator at Columbia University, highlights the study’s methodological advancements, particularly its reliance on registry data to elucidate occupational histories and cognitive demands.

The study’s authors, while presenting these compelling findings, also caution against inferring direct causation between occupational cognitive demands and dementia onset. They note the complexity of such associations and the need for further validation through rigorous longitudinal research. They acknowledge the study’s limitations, including the absence of granular distinctions between cognitive requirements within occupational categories and the dynamic nature of job responsibilities over time.

This groundbreaking study not only underscores the multifaceted influence of occupational cognitive demands and educational attainment on later-life cognitive health but also illuminates the protective effect of engaging in cognitively stimulating occupations during midlife. These findings, which have been published in a prestigious journal, offer valuable insights for policymakers, healthcare practitioners, and individuals alike, underscoring the imperative of fostering intellectually enriching work environments to mitigate the burden of age-related cognitive decline.

More information: Trine H. Edwin et al, Trajectories of Occupational Cognitive Demands and Risk of Mild Cognitive Impairment and Dementia in Later Life, Neurology. DOI: 10.1212/WNL.0000000000209353

Journal information: Neurology Provided by Columbia University Mailman School of Public Health