title: Comorbidity trajectories in working age cancer survivors: A national study of Swedish men.
abstract: A large proportion of cancer survivors are of working age, and maintaining health is of interest both for their working and private life. However, patterns and determinants of comorbidity over time among adult cancer survivors are incompletely described. We aimed to identify distinct comorbidity trajectories and their potential determinants.
  
  
  
  In a cohort study of Swedish men born between 1952 and 1956, men diagnosed with cancer between 2000 and 2003 (n=878) were matched with cancer-free men (n=4340) and followed over five years after their first year of survival. Comorbid diseases were identified using hospital diagnoses and included in the analysis using group-based trajectory modelling. The association of socioeconomic and developmental characteristics were assessed using multinomial logit models.
  
  
  
  Four distinct comorbidity trajectories were identified. As many as 84% of cancer survivors remained at very low levels of comorbidity, and the distribution of trajectories was similar among the cancer survivors and the cancer-free men. Increases in comorbidity were seen among those who had comorbid disease at baseline and among those with poor summary disease scores in adolescence. Socioeconomic characteristics and physical, cognitive and psychological function were associated with types of trajectory in unadjusted models but did not retain independent relationships with them after simultaneous adjustment.
  
  
  
  Among working-age male cancer survivors, the majority remained free or had very low levels of comorbidity. Those with poorer health in adolescence and pre-existing comorbid diseases at cancer diagnosis may, however, benefit from follow-up to prevent further increases in comorbidity.
authors.affiliation: Clinical Epidemiology and Biostatistics, School of Medical Sciences, Örebro University, Örebro, Sweden. Electronic address: Ayako.Hiyoshi@oru.se.
authors.forename: Ayako
authors.initials: A
authors.lastname: Hiyoshi
authors.affiliation: Clinical Epidemiology and Biostatistics, School of Medical Sciences, Örebro University, Örebro, Sweden; Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden. Electronic address: Katja.Fall@oru.se.
authors.forename: Katja
authors.initials: K
authors.lastname: Fall
authors.affiliation: Clinical Epidemiology and Biostatistics, School of Medical Sciences, Örebro University, Örebro, Sweden. Electronic address: Cecilia.Bergh@oru.se.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Bergh
authors.affiliation: Clinical Epidemiology and Biostatistics, School of Medical Sciences, Örebro University, Örebro, Sweden; The Clinical Epidemiology Unit, Department of Medicine, Karolinska Institutet, Stockholm, Sweden; Department of Epidemiology and Public Health, University College London, United Kingdom. Electronic address: Scott.Montgomery@oru.se.
authors.forename: Scott
authors.initials: S
authors.lastname: Montgomery
mesh_terms: D015331:Cohort Studies; D015897:Comorbidity; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000401:mortality*; D017741:Survivors / Q000523:psychology*; D013548:Sweden
keywords: Adolescence; Cancer; Comorbidity; Longitudinal; Risk factor; Survivor; Trajectory