title: Work strain in midlife and 28-year work ability trajectories.
abstract: OBJECTIVE
  We investigated the 28-year development trajectories of work ability among initially middle-aged         male and female municipal employees and the association of perceived mental and physical work strain in midlife by work         ability trajectory groups.
  
  
  METHODS
  The baseline data of the Finnish longitudinal study of municipal employees (FLAME)         were collected in 1981 (N=6257) with follow-ups in 1985, 1992, 1997, and 2009. Work ability was assessed in all         the waves as present perceived work ability relative to lifetime best. Altogether, N=2690 had work ability data in         1981 and 2009, and at least for one wave in between these years, and were included in group-based semi-parametric         mixture modeling trajectory analyses. Baseline differences in mental and physical work strain according to the work         ability trajectories were assessed with MANCOVA (multivariate analysis of covariance).
  
  
  RESULTS
  A five-group work         ability trajectory model was identified for men and a four-group model for women. For the majority, a linear decline         from excellent to moderate or moderate to poor work ability was observed while non-linear trajectories with sudden         collapse and, in some cases, modest subsequent recovery of work ability were also observed. Individuals who maintained         their work ability on an excellent-to-moderate level throughout the follow-up more often reported low mental and         physical work strain in midlife.
  
  
  CONCLUSIONS
  A substantial proportion of individuals seem to maintain their work         ability on a moderate level from midlife to old age. Work strain may have far-reaching negative effects on         individuals' work ability from midlife to old age, warranting vigilance in maintaining and promoting work ability         throughout the lifespan.
authors.affiliation: Gerontology Research Centre, Department of Health Sciences, University of Jyväskylä, PO Box 35-Viveca, FI-40014 University of Jyväskylä, Finland. monika.bonsdorff@jyu.fi
authors.forename: Monika E
authors.initials: ME
authors.lastname: von Bonsdorff
authors.forename: Katja
authors.initials: K
authors.lastname: Kokko
authors.forename: Jorma
authors.initials: J
authors.lastname: Seitsamo
authors.forename: Mikaela B
authors.initials: MB
authors.lastname: von Bonsdorff
authors.forename: Clas-Håkan
authors.initials: CH
authors.lastname: Nygård
authors.forename: Juhani
authors.initials: J
authors.lastname: Ilmarinen
authors.forename: Taina
authors.initials: T
authors.lastname: Rantanen
mesh_terms: D000704:Analysis of Variance; D002055:Burnout, Professional; D004651:Employment; D005260:Female; D005387:Finland; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged