Differential Risk of Cognitive Impairment across Paid and Unpaid Occupations in the Middle-Age Population: Evidence from the Korean Longitudinal Study of Aging, 2006-2016.

To examine and quantify the risk of cognitive impairment across a variety of occupations including unpaid work in a middle-age population using the dataset of a nationally representative longitudinal survey. A total of 20,932 observations of 5865 subjects aged 45-64 were obtained from six waves of the Korean Longitudinal Study of Aging (2006-2016). A dichotomous outcome variable was constructed on the basis of the Korean Versions of the Mini-Mental State Examination scores, and occupations were grouped into 10 occupation categories, including unpaid housekeepers. Socio-demographics, lifestyle, and medical conditions were used as covariates in mixed logistic regression models. Adjusted odds ratios and predicted probabilities of cognitive impairment were computed and adjusted for a complex survey design. In longitudinal models with all studied covariates, the risk of cognitive impairment differed significantly across occupation categories, but the association of occupation with the risk of cognitive impairment was the same between genders. In terms of the predicted probability, the risk of cognitive impairment in the unpaid housekeepers' category (11.2%, 95% confidence interval (CI): 10.4% to 11.9%) was the highest among occupation categories, being three times higher than in the professionals' and related workers' category (3.7%, 95% CI: 1.6% to 5.7%). Public policies based on studies of the risk of cognitive impairment across different occupations in the middle-age population should be designed so as to prevent cognitive impairment in the middle-age population as well as their older life stages, particularly targeting high-risk groups such as people engaged in unpaid domestic and care activities.