title: Breaks and maintenance work in the water distribution systems and gastrointestinal illness: a cohort study.
abstract: BACKGROUND
  During maintenance work or breaks on the water distribution system, water pressure occasionally will be reduced. This may lead to intrusion of polluted water-either at the place of repair or through cracks or leaks elsewhere in the distribution system. The objective of this study was to assess whether breaks or maintenance work in the water distribution system with presumed loss of water pressure was associated with an increased risk of gastrointestinal illness among recipients.
  
  
  METHODS
  We conducted a cohort study among recipients of water from seven waterworks in Norway during 2003-04. One week after an episode of mains breaks or maintenance work on the water distribution system, the exposed and unexposed households were interviewed about gastrointestinal illness in the week following the episode.
  
  
  RESULTS
  During the 1-week period after the episode, 12.7% of the exposed households reported gastrointestinal illness in the household, compared with 8.0% in the unexposed households [risk ratio (RR) 1.58, 95% confidence interval (CI): 1.1, 2.3]. The risk was highest in households with higher average water consumption. The attributable fraction among the exposed households was 37% in the week following exposure.
  
  
  CONCLUSIONS
  Our results show that breaks and maintenance work in the water distribution systems caused an increased risk of gastrointestinal illness among water recipients. Better data on the occurrence of low-pressure episodes and improved registration of mains breaks and maintenance work on the water distribution network are needed in order to assess the public health burden of contamination of drinking water within the distribution network.
authors: Division of Infectious Disease Control, Norwegian Institute of Public Health, Oslo, Norway. kany@fhi.no
authors: Karin
authors: K
authors: Nygård
authors: Erik
authors: E
authors: Wahl
authors: Truls
authors: T
authors: Krogh
authors: Odd Atle
authors: OA
authors: Tveit
authors: Erik
authors: E
authors: Bøhleng
authors: Aage
authors: A
authors: Tverdal
authors: Preben
authors: P
authors: Aavitsland
mesh_terms: D016022:Case-Control Studies; D015331:Cohort Studies; D005759:Gastroenteritis / Q000209:etiology*; D006801:Humans; D016015:Logistic Models; D008283:Maintenance; D009664:Norway; D018570:Risk Assessment / Q000379:methods; D012499:Sanitation; D014876:Water Pollution / Q000009:adverse effects*; D014881:Water Supply