title: The incidence and prevalence of comorbid gastrointestinal, musculoskeletal, ocular, pulmonary, and renal disorders in multiple sclerosis: a systematic review.
abstract: BACKGROUND
  As new disease-modifying therapies emerge a better knowledge of the risk of comorbid disease in multiple sclerosis (MS) is needed.
  
  
  OBJECTIVE
  To estimate the incidence and prevalence of comorbid gastrointestinal, musculoskeletal, ocular, pulmonary, and renal disorders in MS.
  
  
  METHODS
  We systematically reviewed the world literature by searching PUBMED, EMBASE, SCOPUS, the Web of Knowledge, and reference lists of retrieved articles. For selected articles, one reviewer abstracted data using a standardized form. The abstraction was verified by a second reviewer. The quality of all selected studies was assessed. For population-based studies we quantitatively assessed studies using the I² statistic, and conducted random effects meta-analyses.
  
  
  RESULTS
  Study designs were heterogeneous with respect to populations, case definitions, and methods of ascertainment. Incidence of the studied comorbidities was rarely reported. Irritable bowel syndrome and chronic lung disease had a prevalence of more than 10% in the MS population. Irritable bowel syndrome, fibromyalgia, cataracts and glaucoma were more common than expected in the MS population.
  
  
  CONCLUSIONS
  Although they have been the subject of less study than other comorbidities, irritable bowel syndrome, arthritis, and chronic lung disease are common in the MS population and occur more often than expected when compared to the general population.
authors.affiliation: Department of Internal Medicine, University of Manitoba, Winnipeg, Canada/Department of Community Health Sciences, University of Manitoba, Winnipeg, Canada rmarrie@hsc.mb.ca.
authors.forename: Ruth Ann
authors.initials: RA
authors.lastname: Marrie
authors.affiliation: Department of Internal Medicine, University of Manitoba, Winnipeg, Canada.
authors.forename: Nadia
authors.initials: N
authors.lastname: Reider
authors.affiliation: Department of Neurology and Neurotherapeutics, University of Texas Southwestern, Dallas, TX, USA.
authors.forename: Olaf
authors.initials: O
authors.lastname: Stuve
authors.affiliation: Department of Basic Medical Sciences, Neurosciences and Sense Organs, University of Bari, Italy.
authors.forename: Maria
authors.initials: M
authors.lastname: Trojano
authors.affiliation: Department of Neurology, Copenhagen University Hospital Rigshospitalet, Denmark.
authors.forename: Per Soelberg
authors.initials: PS
authors.lastname: Sorensen
authors.affiliation: Department of Biostatistics, University of Alabama at Birmingham, USA.
authors.forename: Gary R
authors.initials: GR
authors.lastname: Cutter
authors.affiliation: Scientific and Clinical Review Associates, LLC, Salisbury, CT, USA.
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Reingold
authors.affiliation: Mellen Center for MS Treatment and Research, Cleveland Clinic, Cleveland, OH, USA.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Cohen
mesh_terms: D015897:Comorbidity; D005128:Eye Diseases / Q000453:epidemiology*; D005767:Gastrointestinal Diseases / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D007674:Kidney Diseases / Q000453:epidemiology*; D008171:Lung Diseases / Q000453:epidemiology*; D009103:Multiple Sclerosis / Q000453:epidemiology*; D009140:Musculoskeletal Diseases / Q000453:epidemiology*; D015995:Prevalence
keywords: Multiple sclerosis; cataracts; comorbidity; gastrointestinal; glaucoma; incidence; lung; prevalence; systematic review