Charlotta Nilsen, PhD, Stress Research Institute, Stockholm University; Aging Research Center, Karolinska Institutet/Stockholm University; Institute of Gerontology, School of Health and Welfare, Jönköping University. Janne Agerholm, PhD, Aging Research Center, Karolinska Institutet/Stockholm University; Department of Global Public Health, Division of Social Medicine, Karolinska Institutet. Susanne Kelfve, PhD, Aging Research Center, Karolinska Institutet/Stockholm University; Department of Culture and Society, Division Ageing and Social Change & Division of Social Work, Linköping University. Jonas W. Wastesson, PhD, Aging Research Center, Karolinska Institutet/Stockholm University; Department of Medical Epidemiology and Biostatistics, Karolinska Institutet Ingemar Kåreholt, PhD, Aging Research Center, Karolinska Institutet/Stockholm University; Institute of Gerontology, School of Health and Welfare, Jönköping University. Bettina Meinow, PhD, Aging Research Center, Karolinska Institutet/Stockholm University; Stockholm Gerontology Research Center. Kirsten Nabe-Nielsen, PhD, Department of Public Health, Section of Social Medicine, University of Copenhagen.
Purpose/Objectives
To investigate associations between different trajectories of occupational complexity across work life and risk of late-life dependency among Swedes aged 70 and older.
Background
Age-related physical and cognitive limitations and poor health may reduce the quality of life and the possibility for independent living. As the older population is growing, this can lead to increased costs for health- and social care in Sweden. There is substantial evidence that work plays a significant role for health, during work life and retirement. Higher occupational complexity has been linked with cognitive aging, such as higher cognitive ability and a reduced risk of developing dementia, and less psychological distress in older ages. In this study, we investigate if different trajectories of occupational complexity across work life is related to late-life dependency.
Methods
Using the Total Population Register, we identified people 70 years or older alive January 1, 2014, and who had not had the outcome (late-life dependency) during two months prior to the start of follow-up. Late-life dependency was operationalized as long-term care use identified through the National Social Service Register, to capture late-life dependency.
We identified debutants of late-life dependency as people 70 years and older who late-life dependency between January 1, 2014 and December 31, 2015. To be considered a debutant, the participants needed to be defined with dependency in personal activities of daily living (PADLs) three months, measures as using homecare with PADLs or >24 hours/month of homecare. By this, we avoid including people with short term dependency. Moving into residential care was defined as dependency from the first month.
Job exposure matrices of occupational complexity were matched to register information on job titles at multiple time points (year 1970, 1975, 1980, 1985, and 1990) in order to create trajectories and measure accumulation.
The job exposure matrix used in this study measures substantive complexity scores. The scores were derived from the Dictionary of Occupational Titles (DOT) using the 1971 Current Population Survey. Substantive complexity comprises eight characteristics. These items were standardised and summed to form a substantive complexity scale. The US occupational categories have been matched with Swedish occupational categories to create substantive complexity scores for Swedish occupations.
The analytic sample consisted of 999,339 participants, 53% female and 47% male.
Statistical analyses
Trajectories of working conditions were assessed with random effects growth curve models to calculate within-person change of working conditions across work life. Hazard regressions with Gompertz distributed baseline intensity were used to estimate hazard ratios (HR) and 95 percent confidence intervals.
The analyses were right-censured when a participant died before the event occurred or the study ended before the event occurred. The analyses were adjusted for gender, age, civil status, country of birth, and level of education at baseline. All statistical analyses were conducted with STATA 15. The statistical analyses provide preliminary findings.
Findings
A total of 9.3% of the study sample (n=93,144) entered late-life dependency during the follow-up. In the fully adjusted model, participants with an initially high starting point of occupational complexity followed by a decreasing trajectory across work life were 7% less likely to enter late-life dependency compared with the reference group, i.e., a low starting point with a decreasing trajectory (HR 0.93, CI 0.90-0.95). Participants with an initially high starting point followed by a stable trajectory were 8% less likely to enter late-life dependency (HR 0.92, CI 0.90-0.94) and having a high starting point followed by an increasing trajectory were 10% less likely (HR 0.90, CI 0.88-0.93) to enter late-life dependency. Having a low starting point of occupational complexity was not statistically significantly associated with late-life dependency, regardless of subsequent trajectory.
Discussion
Having a history of occupational complexity throughout work life was protective of late-life dependency. Most people will spend several years in the “fourth age”, which has been described as the last period in life when we become increasingly dependent on others for the most basic aspects of daily life due to severe disability. The study results highlight the importance of work life to better understand who will be most likely to enter late-life dependency.
Conclusions
From a policy perspective it is relevant to find potentially modifiable predictors of healthy aging to be able to develop strategies and interventions to prevent or delay disability in late life. This study results indicate that working conditions early in the career should be targeted for intervention as it may have cumulative beneficial effects across the work life.