title: Does disability status modify the association between psychosocial job quality and mental health? A longitudinal fixed-effects analysis.
abstract: BACKGROUND
  People with disabilities have difficulties in obtaining work. However, evidence suggests that those with disabilities derive substantial mental health benefits from employment. This paper assesses how the relationship between work and mental health is influenced by psychosocial job quality for people working with a disability.
  
  
  METHODS
  The study design was a longitudinal cohort with 13 annual waves of data collection, yielding a sample of 122,883 observations from 21,848 people. Fixed-effects within-person regression was used to control for time invariant confounding. The Mental Component Summary (MCS) of the Short Form 36 (SF-36) measure was used as the primary outcome measure. The main exposure was a six-category measure of psychosocial job quality and employment status (including 'not in the labour force' [NILF] and unemployment). Disability status ('no waves of disability reported' and 'all contributed waves with reported disability') was assessed as an effect modifier. We also conducted a secondary analysis on respondents contributing both disability and non-disability waves.
  
  
  RESULTS
  For those with no disability, the greatest difference in mental health (compared to optimal employment) occurs when people have the poorest quality jobs (-2.12, 95% CI -2.48, -1.75, p < 0.001). The relative difference in mental health was less in relation to NILF and unemployment (-0.39 and -0.66 respectively). For those with consistent disability, the difference in mental health when employed in an optimal job was similar between the poorest quality jobs (-2.25, 95% CI -3.84, -0.65, p = 0.006), NILF (-2.84, 95% CI -4.49, -1.20, p = 0.001) or unemployment (-2.56, 95% CI -4.32, -0.80, p = 0.004). These results were confirmed by the secondary analysis.
  
  
  CONCLUSIONS
  Efforts to improve psychosocial job quality may have significant mental health benefits for people with disabilities. This will contribute to the economic viability of disability employment insurance schemes in Australia and other high-income countries.
authors.affiliation: Deakin University, Australia. Electronic address: Allison.milner@deakin.edu.au.
authors.forename: A
authors.initials: A
authors.lastname: Milner
authors.affiliation: University of Melbourne, Australia.
authors.forename: L
authors.initials: L
authors.lastname: Krnjacki
authors.affiliation: The Australian National University, Australia.
authors.forename: P
authors.initials: P
authors.lastname: Butterworth
authors.affiliation: University of Melbourne, Australia.
authors.forename: A
authors.initials: A
authors.lastname: Kavanagh
authors.affiliation: Deakin University, Australia.
authors.forename: Anthony D
authors.initials: AD
authors.lastname: LaMontagne
mesh_terms: D000328:Adult; D001315:Australia; D006233:Persons with Disabilities / Q000523:psychology*; D004651:Employment / Q000523:psychology; D005260:Female; D006801:Humans; D007588:Job Satisfaction; D008137:Longitudinal Studies; D008297:Male; D008603:Mental Health; D008875:Middle Aged; D014478:Unemployment / Q000523:psychology; D014937:Work / Q000523:psychology*
keywords: Disability; Economic inactivity; Job stress; Mental health; Occupation; Psychosocial job quality; Unemployment