Routine-task intensity was associated with risk for mild cognitive impairment and dementia in an observational study.

Cognitively stimulating activities may delay the onset of mild cognitive impairment and dementia. In this study, researchers longitudinally investigated whether occupational cognitive demands from ages 30 to 65 years were associated with clinical diagnoses of mild cognitive impairment and dementia after age 70 years. Participants were from one county in Norway and had at least one occupational assessment before age 50 years and one at or after age 50 years. The researchers measured occupational cognitive demands using a routine-­task intensity index for 305 occupations, where lower routine-­task intensity indicated a more cognitively demanding occupation. Mild cognitive impairment and dementia were determined at age 69 years or older based on Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, criteria. Covariates included age, sex, education, income during peak work years, hypertension before age 50 years, obesity, diabetes, psychiatric impairment, hearing impairment, loneliness, smoking status and physical inactivity.

Among 7003 participants (49.8% women; age range at cognitive assessment, 69 to 104 years), the investigators identified four routine-­task intensity trajectory groups: 20% had low routine­ task intensity (e.g. teaching professionals), 23% had intermediate-­low routine-­task intensity (e.g. childcare workers), 37% had intermediate-­high routine-­task intensity (e.g. retail salespersons and nursing assistants) and 20% had high routine-task intensity (e.g. sorting clerks). Compared with the low routine-­task intensity group, the intermediate-low, intermediate-­high and high routine-task intensity groups had increased risks for mild cognitive impairment and dementia after adjustment for age and sex. The risk attenuated but remained significant for mild cognitive impairment after further adjustment for education and other covariates. A significant dementia risk remained only for the high routine-­task intensity group after further adjustment for education and was no longer significant after adjustment for the other covariables.

Comment: These results support the encouragement of occupational cognitive stimulation for people in their 30s to 60s to optimise cognition after age 70 years. Incorporating data on race is needed to more fully understand the effect of occupational demands on cognition.

Jennifer Rose V. Molano, MD, Associate Professor, Department of Neurology and Rehabilitation Medicine, The University of Cincinnati, Ohio, USA.

Edwin TH, et al. Trajectories of occupational cognitive demands and risk of mild cognitive impairment and dementia in later life: the HUNT4 70+ study. Neurology 2024; 102: e209353.

This summary is taken from the following Journal Watch title: Neurology.