title: Ambient Temperature and the Risk of Renal Colic: A Population-Based Study of the Impact of Demographics and Comorbidity.
abstract: To examine the impact of ambient temperature on the incidence of emergency department (ED) admissions for acute renal colic and the potential influence demographics and comorbid conditions may have on this.
  
  
  
  We conducted a population-based time series analysis using linked healthcare databases in Ontario, Canada, which included all residents, aged ≥19 years, who were admitted to an ED from April 2002 to December 2013. The primary outcome was daily number of renal colic emergency department admissions. A distributed lag nonlinear model with 21 days of lag was applied to estimate the cumulative effect of temperature on colic admissions. We estimated risks for cold and heat, defined as temperatures below and above the optimal temperature, which corresponded to the point with minimum risk of colic admissions. We conducted stratified analyses using selected demographics and comorbidities.
  
  
  
  During the study period, 423,396 patients presented to an ED with colic. There was a significantly increased risk of colic as ambient temperature increased (rate ratio [RR] = 1.30, 95% confidence interval [CI]: 1.20, 1.42). Subgroup analysis demonstrated an increased risk associated with heat for both genders; however, this risk was more pronounced in males with extreme heat (RR = 1.64 vs 1.22, p = 0.006). In contrast to other age groups, there was an increased risk for those in their 40s (RR = 1.42), 50s (RR = 1.54), and 60s (RR = 1.31) (p = 0.02).
  
  
  
  Increasing ambient temperature was associated with increased risk of ED visits for colic, particularly in males and those aged 40 to 69 years.
authors.affiliation: 1 Division of Urology, Department of Surgery, St. Michael's Hospital, University of Toronto , Toronto, Ontario, Canada .|2 Institute for Clinical Evaluative Sciences , Toronto, Ontario, Canada .
authors.forename: Michael
authors.initials: M
authors.lastname: Ordon
authors.affiliation: 2 Institute for Clinical Evaluative Sciences , Toronto, Ontario, Canada .|3 Division of Urology, Department of Surgery, St. Joseph's Health Care, Western University , London, Ontario, Canada .|4 Department of Epidemiology and Biostatistics, Schulich School of Medicine and Dentistry, Western University , London, Ontario, Canada .
authors.forename: Blayne
authors.initials: B
authors.lastname: Welk
authors.affiliation: 5 Public Health Ontario , Toronto, Ontario, Canada .
authors.forename: Qiongsi
authors.initials: Q
authors.lastname: Li
authors.affiliation: 5 Public Health Ontario , Toronto, Ontario, Canada .
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
authors.affiliation: 6 Air Health Science Division, Health Canada , Ottawa, Ontario, Canada .|7 School of Epidemiology, Public Health and Preventive Medicine, University of Ottawa , Ontario, Canada .
authors.forename: Eric
authors.initials: E
authors.lastname: Lavigne
authors.affiliation: 8 Climate Change and Health Office, Health Canada , Ottawa, Ontario, Canada .
authors.forename: Abderrahmane
authors.initials: A
authors.lastname: Yagouti
authors.affiliation: 5 Public Health Ontario , Toronto, Ontario, Canada .|9 Dalla Lana School of Public Health, University of Toronto , Toronto, Ontario, Canada .
authors.forename: Ray
authors.initials: R
authors.lastname: Copes
authors.affiliation: 10 Population Studies Division, Health Canada , Ottawa, Ontario, Canada .
authors.forename: Sabit
authors.initials: S
authors.lastname: Cakmak
authors.affiliation: 2 Institute for Clinical Evaluative Sciences , Toronto, Ontario, Canada .|5 Public Health Ontario , Toronto, Ontario, Canada .|9 Dalla Lana School of Public Health, University of Toronto , Toronto, Ontario, Canada .
authors.forename: Hong
authors.initials: H
authors.lastname: Chen
mesh_terms: D000328:Adult; D000368:Aged; D003080:Cold Temperature; D015897:Comorbidity; D016208:Databases, Factual; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D005260:Female; D006760:Hospitalization; D006358:Hot Temperature; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009864:Ontario / Q000453:epidemiology; D010343:Patient Admission; D056844:Renal Colic / Q000453:epidemiology*; D012307:Risk Factors; D013696:Temperature; D055815:Young Adult
keywords: comorbidity; demography; nephrolithiasis; renal colic; temperature