title: The effect of high ambient temperature on emergency room visits.
abstract: BACKGROUND
  The association between temperature and mortality has been widely researched, although the association between temperature and morbidity has been less studied. We examined the association between mean daily apparent temperature and emergency room (ER) visits in California.
  
  
  METHODS
  We used a time-stratified case-crossover design, restricting our data to the warm seasons of 2005-2008 in 16 climate zones. The study population included cases residing within 10 km of meteorologic monitors. Conditional logistic regression models with apparent temperature were applied by climate zone; these models were then combined in meta-analyses to estimate overall effects. Our analyses considered the effects by disease subgroup, race/ethnic group, age group, and potential confounding by air pollutants.
  
  
  RESULTS
  More than 1.2 million ER visits were included. Positive associations were found for same-day apparent temperature and ischemic heart disease (% excess risk per 10°F = 1.7 [95% confidence interval = 0.2 to 3.3]), ischemic stroke (2.8 [0.9 to 4.7]), cardiac dysrhythmia (2.8 [0.9 to 4.9]), hypotension (12.7 [8.3 to 17.4]), diabetes (4.3 [2.8 to 5.9]), intestinal infection (6.1 [3.3 to 9.0]), dehydration (25.6 [21.9 to 29.4]), acute renal failure (15.9 [12.7 to 19.3]), and heat illness (393.3 [331.2 to 464.5]). Negative associations were found for aneurysm, hemorrhagic stroke, and hypertension. Most of these estimates remained relatively unchanged after adjusting for air pollutants. Risks often varied by age or racial/ethnic group.
  
  
  CONCLUSIONS
  Increased temperatures were found to have same-day effects on ER admission for several outcomes. Age and race/ethnicity seemed to modify some of these impacts.
authors.affiliation: California Office of Environmental Health Hazard Assessment, Air Pollution Epidemiology Section, Oakland, CA 94612, USA. Rupa.Basu@oehha.ca.gov
authors.forename: Rupa
authors.initials: R
authors.lastname: Basu
authors.forename: Dharshani
authors.initials: D
authors.lastname: Pearson
authors.forename: Brian
authors.initials: B
authors.lastname: Malig
authors.forename: Rachel
authors.initials: R
authors.lastname: Broadwin
authors.forename: Rochelle
authors.initials: R
authors.lastname: Green
mesh_terms: D000328:Adult; D000393:Air Pollutants / Q000032:analysis; D002140:California / Q000453:epidemiology; D002318:Cardiovascular Diseases / Q000453:epidemiology*; D015984:Causality; D002980:Climate; D015897:Comorbidity; D018592:Cross-Over Studies; D003681:Dehydration / Q000453:epidemiology; D003920:Diabetes Mellitus / Q000453:epidemiology; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D004784:Environmental Monitoring / Q000706:statistics & numerical data; D005260:Female; D005759:Gastroenteritis / Q000453:epidemiology; D018883:Heat Stroke / Q000453:epidemiology; D006358:Hot Temperature; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D012140:Respiratory Tract Diseases / Q000453:epidemiology*; D018570:Risk Assessment; D012621:Seasons; D055815:Young Adult
chemical_list: D000393:Air Pollutants