title: An internet-based health survey on the co-morbidities of choroideremia patients.
abstract: OBJECTIVE
  To examine the prevalence of systemic and ocular disease among choroideremia patients and carriers.
  
  
  METHODS
  A cross-sectional analysis was performed on responses from affected males with choroideremia, female carriers, and unaffected brothers to an Internet-based survey made available from September 2009 to November 2010. Affected males were classified into two groups, those with or without functional vision. Carrier females were classified into those with and without symptoms. Comparisons were made between these groups.
  
  
  RESULTS
  There was a higher prevalence of dry eye in our respondents than the North American population. The prevalence of dry eye, cataract, hypertension, diabetes, psychological problems and hypercholesterolemia were higher in choroideremia males without functional vision compared to those with functional vision. Likewise, statin intake was more prevalent among the affected males without functional vision than those with functional vision. After age adjustment, any differences between the two subgroups of male patients (with and without functional vision) were not significant.
  
  
  CONCLUSIONS
  Age plays an important role in determining the onset of severe visual impairment with loss of functional vision in male subjects affected by choroideremia. Although Internet surveys have limitations such as the use of self-reported diagnoses and the possibility that the responses may not be representative of the population as a whole, this study shows that such surveys can provide data quickly and easily, and for rare diseases such as choroideremia, with relatively large numbers of responses.
authors.affiliation: Department of Ophthalmology, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Zhou
authors.forename: Ekekiel
authors.initials: E
authors.lastname: Weis
authors.forename: Ming
authors.initials: M
authors.lastname: Ye
authors.forename: Shelly
authors.initials: S
authors.lastname: Benjaminy
authors.forename: Ian M
authors.initials: IM
authors.lastname: MacDonald
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002170:Canada / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D015794:Choroideremia / Q000453:epidemiology* / Q000235:genetics; D015897:Comorbidity; D003430:Cross-Sectional Studies; D005128:Eye Diseases / Q000453:epidemiology*; D005260:Female; D006306:Health Surveys / Q000379:methods; D006579:Heterozygote; D006801:Humans; D020407:Internet; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011795:Surveys and Questionnaires; D014481:United States / Q000453:epidemiology; D055815:Young Adult