title: Mortality and hospital admission rates for unintentional nonfire-related carbon monoxide poisoning across Canada: a trend analysis.
abstract: BACKGROUND
  The epidemiology of mortality and morbidity from carbon monoxide poisoning in Canada has received little attention. Our objective was to evaluate trends in mortality and hospital admission rates for unintentional nonfire-related carbon monoxide poisoning across Canada.
  
  
  METHODS
  Age- and sex-standardized mortality (1981-2009) and hospital admission (1995-2010) rates by age group, sex and site of carbon monoxide exposure were calculated for each province and for all of Canada. We quantified the long-term trends by calculating the average annual percent change. Multivariable Poisson regression was used to estimate incidence rate ratios (IRRs) of carbon monoxide poisoning across age groups, sex and month of occurrence.
  
  
  RESULTS
  In Canada, there were 1808 unintentional nonfire-related carbon monoxide poisoning deaths between 1981 and 2009 and 1984 admissions to hospital between 1995 and 2010. Average annual decreases of 3.46% (95% confidence interval [CI] -4.59% to -2.31%) and 5.83% (95% CI -7.79% to -3.83%) were observed for mortality and hospital admission rates, respectively. Mortality (IRR 5.31, 95% CI 4.57 to 6.17) and hospital admission (IRR 2.77, 95% CI 2.51 to 3.03) rates were elevated in males compared with females. Decreased trends in the rates were observed for all sites of carbon monoxide exposure, but the magnitude of this decrease was lowest in residential environments. Deaths and admissions to hospital were most frequent from September to April, with peaks in December and January.
  
  
  CONCLUSIONS
  Mortality and hospital admission rates for unintentional nonfire-related carbon monoxide poisoning in Canada have declined steadily. Continued efforts should focus on reducing carbon monoxide poisoning during the cooler months and in residential environments.
authors.affiliation: Air Health Science Division, Health Canada, Ottawa, Ont. ; Interdisciplinary School of Health Sciences, University of Ottawa, Ottawa, Ont.
authors.forename: Eric
authors.initials: E
authors.lastname: Lavigne
authors.affiliation: Air Health Science Division, Health Canada, Ottawa, Ont. ; McGill University, Department of Epidemiology, Biostatistics and Occupational Health, Montréal, Que.
authors.forename: Scott
authors.initials: S
authors.lastname: Weichenthal
authors.affiliation: Air Health Science Division, Health Canada, Ottawa, Ont.
authors.forename: Joan
authors.initials: J
authors.lastname: Wong
authors.affiliation: Population Studies Division, Health Canada, Ottawa, Ont.
authors.forename: Marc
authors.initials: M
authors.lastname: Smith-Doiron
authors.affiliation: Air Health Science Division, Health Canada, Ottawa, Ont.
authors.forename: Rose
authors.initials: R
authors.lastname: Dugandzic
authors.affiliation: British Columbia Centre for Disease Control, Vancouver, BC.
authors.forename: Tom
authors.initials: T
authors.lastname: Kosatsky