The aim of this study was to investigate whether sick leave due to different mental disorders increased the risk of reoccurring sick-leave, disability pension and unemployment, taking genetics and shared environment into account.
This register-based cohort study contains 2202 discordant twin pairs 18-64 years old, where one twin had sick leave due to a mental disorder 2005-2006. The end of the sick-leave spell was the start of follow-up for both twins. The twins were followed up for reoccurring sick-leave, disability pension and unemployment (> 180 days in a year), until December 2012. Analyses were censored for disability pension, death, emigration and old-age pension. Cox proportional hazards models with time-varying covariates were used to calculate hazard ratios with 95% confidence intervals (CI).
Those with sick leave due to mental disorders had a 3.64 (CI: 3.24-4.08) times higher risk of reoccurring sick-leave within the first two years; after that, hazard ratios were attenuated and explained by genetic factors. The first year, they had 12.24 (CI: 8.11-18.46) times the risk of disability pension. The risk was attenuated but remained at 2.75 (CI: 2.07-3.65) after one year. The risk of unemployment was 1.99 (CI: 1.72-2.31) during the whole follow-up period. The risk of unemployment and disability pension was lower for those with stress-related than other mental disorders, this was less clear for recurrent reoccuring sick-leave.
Sick leave due to mental disorders increased the risk of reoccurring sick-leave within two years, disability pension and unemployment, independent of genetics and shared environment.
Sickness absence (SA) is becoming a major economic problem in many countries. Our aim was to investigate whether type of employment, including temporary employment or part-time employment, is associated with SA while controlling for familial factors (genetic and shared environment). Differences between men and women and across employment sectors were explored.
This is a prospective twin study based on 21 105 twins born in Sweden 1959-85. The participants completed a survey in 2005 with follow-up of SA (=15 days), using register data, until end of 2013. The data were analyzed with logistic regression, with results presented as odds ratios (OR) with 95% confidence intervals (CI).
Temporary employment involved higher odds of SA (OR=1.21 95% CI=1.04-1.40) compared to full-time employment. Both part-time workers (OR=0.84 95% CI=0.74-0.95) and the self-employed (OR=0.77 95%CI=0.62-0.94) had lower odds of SA. Stratifying by sex showed lower odds for part-timers (OR=0.82 95% CI=0.73-0.94) and self-employed women (OR=0.65 95% CI=0.47-0.90), but higher odds for men in temporary employment (OR=1.33 95% CI=1.03-1.72). Temporary employees in county councils (OR=1.73 95% CI=1.01-2.99) and municipalities (OR=1.41 95% CI=1.02-1.96) had higher odds while part-timers employed in the private sector had lower odds (OR=0.77 95% CI=0.64-0.93). Familial factors did not confound the association between employment type and SA.
Employment type is associated with SA, with temporary employment involving a higher risk compared to permanent full-time employment while both part-time employment and self-employment involved a lower risk. The associations vary between women and men and across sectors.
This study aims to assess whether the associations between burnout and sick leave due to stress-related mental disorders, other mental disorders, and somatic conditions are influenced by familial (genetic and shared environmental) factors.
In this prospective cohort study, 23,611 Swedish twins born between 1959 and 1985, who answered a web-based questionnaire, including the Pines Burnout Measure 2004-2006, were included. Registry data on sick leave spells from the response date until December 31, 2010 were obtained from the Swedish Social Insurance Agency. Logistic regression analysis was performed to assess odds ratios with 95% confidence intervals for the association between burnout and sick leave for the whole sample, while conditional logistic regression of the same-sex discordant twin pairs was used to estimate the association between burnout and sick leave, adjusting for familial confounding. The Bivariate Cholesky models were used to assess whether the covariation between burnout and sick leave was explained by common genetic and/or shared environmental factors.
Burnout was a risk factor for sick leave due to stress-related and other mental disorders, and these associations were explained by familial factors. The phenotypic correlation between burnout and sick leave due to somatic conditions was 0.07 and the association was not influenced by familial factors. The phenotypic correlations between burnout and sick leave due to stress-related (0.26) and other mental disorders (0.30) were completely explained by common genetic factors.
The association between burnout and sick leave due to stress-related and other mental disorders seems to be a reflection of a shared genetic liability.