Difference in employment status and onset of disability among Japanese community-dwelling older adults: a prospective cohort study.

Abstract

This prospective cohort study investigates the relationship between the onset of disability and employment status. We investigated 3,741 community-dwelling adults aged 70 or older, who participated in a population-based cohort study in Japan. Their onset of disability was monitored monthly using the long-term care insurance certification registration system, for five years from baseline. Based on an employment status questionnaire, we categorized participants into three groups: (1) employee, (2) self-employed, and (3) not working. Covariates included demographic information, medical history, number of medications, educational level, living alone, social group engagement, smoking status, walking speed, instrumental activities of daily living, global cognitive function, and depressive symptoms. Missing values were managed using multiple imputation. Cox proportional hazard models were used to calculate hazard ratios (HRs) with 95% confidence intervals (CIs) for incident disability risk by employment status. The disability incidence rates were 15.3/1,000 (95% CIs: 10.7-22.0) person-years among employees, and 33.0/1000 (95% CIs: 24.4-44.6) and 39.6/1000 (95% CIs: 36.5-43.0) person-years among self-employed and non-working participants, respectively. The adjusted HRs for the onset of disability among non-working and self-employed participants were 1.69 (95% CIs: 1.16-2.46, p = 0.007) and 1.63 (95% CIs: 1.01-2.62, p = 0.044) compared with employees, respectively. Similar results were found among men. Among women, disability onset was not associated with employment status. Older adults' risk of disability onset differed according to their employment status. Older employees had a lower risk of disability onset than those not working or self-employed.