Objectives Despite growing employment levels in the geriatric population, there exists little evidence regarding the specific relationship between occupation and health for older individuals. We investigated the impact of occupation on cognitive and physical function within an occupational window of the past 15 years using a nationally representative sample in Korea.

Methods A total of 4,408 subjects aged 60 and older were selected from the Korean Longitudinal Study of Ageing (KLoSA). Functional health was evaluated using the Korean versions of the Mental State Examination (K-MMSE), Instrumental Activities of Daily Living (K-IADL), and Activities of Daily Living (K-ADL) measures. Work duration during the past 15 years was based on subjects’ occupational history record and classified into four categories; unemployment, ≤7years, 8~15 years, and ≥15 years. Sociodemographic characteristics, and general health information were recorded as key independent variables.

Results The risks of cognitive impairment and disability in women were higher than those in men, and currently employed subjects displayed good cognitive and physical function. Longer work duration significantly and positively affected all measures of function (MMSE p for trend = 0.0151; IADL p for trend = 0.0007; ADL p for trend = 0.0002) in men, whereas it only improved physical function in women (IADL p for trend = 0.0449; ADL p for trend = 0.0362). Manual labourers exhibited improved functional capacity with longer work durations over the past 15 years (MMSE p for trend = 0.0328; IADL p for trend = 0.0044; ADL p for trend = 0.0004), although they presented lower functional scores compared with their counterparts. There was a curvilinear relationship between work duration and function among men and manual labourers.

Conclusions Older Korean people in our study who continued to work exhibited improved cognitive and physical function. We suggest that longer work duration, especially for men and for manual labourers, is a significant contributor to better cognitive and physical function of older people.