title: Extreme Precipitation and Emergency Room Visits for Gastrointestinal Illness in Areas with and without Combined Sewer Systems: An Analysis of Massachusetts Data, 2003-2007.
abstract: BACKGROUND
  Combined sewer overflows (CSOs) occur in combined sewer systems when sewage and stormwater runoff are released into water bodies, potentially contaminating water sources. CSOs are often caused by heavy precipitation and are expected to increase with increasing extreme precipitation associated with climate change.
  
  
  OBJECTIVE
  The aim of this study was to assess whether the association between heavy rainfall and rate of emergency room (ER) visits for gastrointestinal (GI) illness differed in the presence of CSOs.
  
  
  METHODS
  For the study period 2003-2007, time series of daily rate of ER visits for GI illness and meteorological data were organized for three exposure regions: a) CSOs impacting drinking water sources, b) CSOs impacting recreational waters, c) no CSOs. A distributed lag Poisson regression assessed cumulative effects for an 8-day lag period following heavy (≥ 90th and ≥ 95th percentile) and extreme (≥ 99th percentile) precipitation events, controlling for temperature and long-term time trends.
  
  
  RESULTS
  The association between extreme rainfall and rate of ER visits for GI illness differed among regions. Only the region with drinking water exposed to CSOs demonstrated a significant increased cumulative risk for rate (CRR) of ER visits for GI for all ages in the 8-day period following extreme rainfall: CRR: 1.13 (95% CI: 1.00, 1.28) compared with no rainfall.
  
  
  CONCLUSIONS
  The rate of ER visits for GI illness was associated with extreme precipitation in the area with CSO discharges to a drinking water source. Our findings suggest an increased risk for GI illness among consumers whose drinking water source may be impacted by CSOs after extreme precipitation.
  
  
  BACKGROUND
  Jagai JS, Li Q, Wang S, Messier KP, Wade TJ, Hilborn ED. 2015. Extreme precipitation and emergency room visits for gastrointestinal illness in areas with and without combined sewer systems: an analysis of Massachusetts data, 2003-2007. Environ Health Perspect 123:873-879; http://dx.doi.org/10.1289/ehp.1408971.
authors: Division of Environmental and Occupational Health Sciences, School of Public Health, University of Illinois, Chicago, Illinois, USA.
authors: Jyotsna S
authors: JS
authors: Jagai
authors: Quanlin
authors: Q
authors: Li
authors: Shiliang
authors: S
authors: Wang
authors: Kyle P
authors: KP
authors: Messier
authors: Timothy J
authors: TJ
authors: Wade
authors: Elizabeth D
authors: ED
authors: Hilborn
mesh_terms: D060766:Drinking Water / Q000009:adverse effects; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005767:Gastrointestinal Diseases / Q000453:epidemiology* / Q000209:etiology; D006801:Humans; D008404:Massachusetts / Q000453:epidemiology; D011891:Rain; D011998:Recreation; D062065:Wastewater / Q000633:toxicity*; D014881:Water Supply
chemical_list: D060766:Drinking Water; D062065:Wastewater