title: Chronic lung disease and multiple sclerosis: Incidence, prevalence, and temporal trends.
abstract: OBJECTIVE
  We aimed to estimate the incidence and prevalence of chronic lung disease (CLD), including asthma and chronic obstructive pulmonary disease, in the MS population versus a matched cohort from the general population.
  
  
  METHODS
  We used population-based administrative data from four Canadian provinces to identify 44,452 persons with MS and 220,849 age-, sex- and geographically-matched controls aged 20 years and older. We employed a validated case definition to estimate the incidence and prevalence of CLD over the period 1995-2005, and used Poisson regression to assess temporal trends.
  
  
  RESULTS
  In 2005, the crude incidence of CLD per 100,000 persons was 806 (95%CI: 701-911) in the MS population, and 757 in the matched population (95%CI: 712-803). In 2005, the crude prevalence of CLD was 13.5% (95%CI: 13.1-14.0%) in the MS population, and 12.4% (95%CI: 12.3-12.6%) in the matched population. Among persons aged 20-44 years, the average annual incidence of CLD was higher in the MS population than in the matched population (RR 1.15; 95%CI: 1.02-1.30), but did not differ between populations for those aged ≥45 years. The incidence of CLD was stable, but the prevalence of CLD increased 60% over the study period.
  
  
  CONCLUSIONS
  CLD is relatively common in the MS population. The incidence of CLD has been stable over time, but the prevalence of CLD has increased. Among persons aged 20-44 years, CLD is more common in the MS population than in a matched population. Given the prevalence of CLD in the MS population, further attention to the effects of CLD on outcomes in MS and approaches to mitigating those effects are warranted.
authors.affiliation: Department of Internal Medicine, University of Manitoba, Winnipeg, Canada; Department of Community Health Sciences, University of Manitoba, Winnipeg, Canada. Electronic address: rmarrie@hsc.mb.ca.
authors.forename: Ruth Ann
authors.initials: RA
authors.lastname: Marrie
authors.affiliation: Department of Community Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, Canada.
authors.forename: Scott
authors.initials: S
authors.lastname: Patten
authors.affiliation: Department of Medicine (Neurology) and Centre for Brain Health, University of British Columbia, Vancouver, Canada.
authors.forename: Helen
authors.initials: H
authors.lastname: Tremlett
authors.affiliation: Department of Community Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, Canada; Surveillance and Assessment Branch, Alberta Ministry of Health, Edmonton, Canada; School of Public Health, University of Alberta, Edmonton, Canada.
authors.forename: Lawrence W
authors.initials: LW
authors.lastname: Svenson
authors.affiliation: Department of Epidemiology and Biostatistics and Occupational Health, McGill University, Montreal, Canada.
authors.forename: Christina
authors.initials: C
authors.lastname: Wolfson
authors.affiliation: Department of Community Health Sciences, University of Manitoba, Winnipeg, Canada; Public Health, Manitoba Health Healthy Living and Seniors, Winnipeg, Canada.
authors.forename: B Nancy
authors.initials: BN
authors.lastname: Yu
authors.affiliation: Department of Community Health Sciences, University of Manitoba, Winnipeg, Canada.
authors.forename: Lawrence
authors.initials: L
authors.lastname: Elliott
authors.affiliation: Faculty of Nursing, University of Alberta, Canada.
authors.forename: Joanne
authors.initials: J
authors.lastname: Profetto-McGrath
authors.affiliation: Faculty of Rehabilitation Medicine, University of Alberta, Canada.
authors.forename: Sharon
authors.initials: S
authors.lastname: Warren
authors.affiliation: Department of Community Health Sciences, University of Manitoba, Winnipeg, Canada.
authors.forename: Stella
authors.initials: S
authors.lastname: Leung
authors.affiliation: Department of Community Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, Canada; Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Canada.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Jette
authors.affiliation: Department of Medicine, Dalhousie University, Halifax, Canada; Nova Scotia Health Authority, Canada.
authors.forename: Virender
authors.initials: V
authors.lastname: Bhan
authors.affiliation: Nova Scotia Health Authority, Canada; Departments of Psychiatry, Psychology & Neuroscience, and Medicine, Dalhousie University, Halifax, Canada.
authors.forename: John D
authors.initials: JD
authors.lastname: Fisk
mesh_terms: D000328:Adult; D002170:Canada / Q000453:epidemiology; D002908:Chronic Disease; D015331:Cohort Studies; D005260:Female; D006801:Humans; D015994:Incidence; D008171:Lung Diseases / Q000150:complications* / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D009103:Multiple Sclerosis / Q000150:complications* / Q000453:epidemiology*; D015995:Prevalence; D055815:Young Adult
keywords: Administrative data; Chronic lung disease; Cohort studies; Incidence; Multiple sclerosis; Prevalence