title: Joint symptoms after a large waterborne gastroenteritis outbreak--a controlled, population-based questionnaire study.
abstract: OBJECTIVE
  Waterborne outbreaks offer an opportunity to study joint symptoms after a simultaneous exposure. In November 2007, a gastroenteritis outbreak due to faecal contamination of tap water took place in a Finnish town. The purpose of this study was to evaluate the occurrence of joint symptoms after the outbreak.
  
  
  METHODS
  The authors conducted a controlled, population-based questionnaire survey to study the occurrence of joint symptoms within 8 weeks after the exposure. The survey covered three areas: contaminated and uncontaminated parts of the town and a control town. A total of 1000 residents were randomly selected from each area, and the joint symptoms were first analysed separately and thereafter categorized as arthritis-like if joint swelling, redness, warmth or pain in movement was reported.
  
  
  RESULTS
  A total of 2123 responses could be evaluated. The overall prevalence of joint symptoms was 13.9% in the contaminated group, 4.3% in the uncontaminated group and 1.5% among the control group, and the frequency of arthritis-like symptoms in the groups was 6.7, 2.1 and 0.5%, respectively. Gastrointestinal symptoms predicted joint complaints, diarrhoea and blood in faeces being the most significant. Residing in the contaminated area was associated with any joint symptom [odds ratio (OR) = 4.0, 95% CI 1.8, 9.0] and joint pain (OR = 7.3, 95% CI 2.1, 24.8) without preceding gastroenteritis.
  
  
  CONCLUSIONS
  The frequency of joint symptoms was high in the contaminated group and also increased in the uncontaminated group. Furthermore, the risk of joint symptoms was increased in the contaminated group even without gastroenteritis.
authors: Department of Internal Medicine, Tampere University Hospital, Finland. janne.laine@pshp.fi
authors: Janne
authors: J
authors: Laine
authors: Terhi
authors: T
authors: Uotila
authors: Jaakko
authors: J
authors: Antonen
authors: Markku
authors: M
authors: Korpela
authors: Eila
authors: E
authors: Kujansuu
authors: Jukka
authors: J
authors: Lumio
authors: Elisa
authors: E
authors: Huovinen
authors: Jukka
authors: J
authors: Mustonen
authors: Petri
authors: P
authors: Ruutu
authors: Mikko J
authors: MJ
authors: Virtanen
authors: Markku
authors: M
authors: Kuusi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001424:Bacterial Infections / Q000453:epidemiology* / Q000382:microbiology; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D003967:Diarrhea / Q000453:epidemiology / Q000382:microbiology; D004196:Disease Outbreaks; D005243:Feces / Q000382:microbiology; D005260:Female; D005387:Finland / Q000453:epidemiology; D005759:Gastroenteritis / Q000453:epidemiology* / Q000382:microbiology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007592:Joint Diseases / Q000453:epidemiology* / Q000382:microbiology; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D011795:Surveys and Questionnaires; D014871:Water Microbiology; D014881:Water Supply / Q000592:standards; D055815:Young Adult