title: Even low levels of ambient air pollutants are associated with increased emergency department visits for hypertension.
abstract: BACKGROUND
  Numerous studies have reported associations between air pollution and cardiovascular diseases. While several studies illustrate that exposures to air pollutants can elevate blood pressure, few have evaluated the clinical relevance of this relationship. Hence, we aimed to explore the associations between daily concentrations of several air pollutants and emergency department visits for hypertension.
  
  
  METHODS
  Odds ratios (ORs) for emergency department visits for hypertension in Edmonton, Canada, from April 1992 to March 2002 were associated with pollutant levels (CO, NO(2), SO(2), O(3), and particulate matter [PM] < 10 microns [PM(10)] and < 2.5 microns [PM(2.5)] in aerodynamic diameter, respectively) by means of a case-crossover technique with time-stratified strategy to define controls. The analysis was performed for all (N = 5365), male (N = 2069), and female (N = 3296) patients and for six air pollutants lagged by 0 to 9 days. ORs and their 95% confidence intervals (CIs) were reported for an increase in an interquartile range (IQR) for each pollutant.
  
  
  RESULTS
  We observed associations for all patients and levels of NO(2) (IQR = 12.8 parts per billion; OR, 1.06; 95% CI, 1.00-1.12), SO(2) (IQR = 2.3 parts per billion; OR, 1.04; 95% CI, 1.00-1.08), and PM(10) (IQR = 15.0 μg/m(3); OR, 1.06; 95% CI, 1.01-1.11) for lag day 3, as well as for PM(10) (IQR = 15.0 μg/m(3); OR, 1.06; 95% CI, 1.01-1.11) and PM(2.5) (IQR = 6.2 μg/m(3); OR, 1.07; 95% CI, 1.01-1.11) for lag day 6.
  
  
  CONCLUSIONS
  These findings support the contention that ambient pollution can produce clinically meaningful increases in blood pressure.
authors.affiliation: Population Studies Division, Health Canada, Ottawa, Ontario, Canada. mietek.szyszkowicz@hc-sc.gc.ca
authors.forename: Mieczysław
authors.initials: M
authors.lastname: Szyszkowicz
authors.forename: Brian H
authors.initials: BH
authors.lastname: Rowe
authors.forename: Robert D
authors.initials: RD
authors.lastname: Brook
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000393:Air Pollutants / Q000009:adverse effects*; D001795:Blood Pressure Determination; D002170:Canada; D016001:Confidence Intervals; D003430:Cross-Sectional Studies; D016208:Databases, Factual; D004630:Emergencies; D004636:Emergency Service, Hospital / Q000706:statistics & numerical data*; D004781:Environmental Exposure / Q000009:adverse effects*; D004784:Environmental Monitoring; D062665:Epidemiological Monitoring; D005260:Female; D006801:Humans; D006973:Hypertension / Q000453:epidemiology* / Q000209:etiology / Q000503:physiopathology*; D015994:Incidence; D016015:Logistic Models; D008297:Male; D008452:Maximum Allowable Concentration; D008875:Middle Aged; D009585:Nitrogen Dioxide / Q000032:analysis; D016017:Odds Ratio; D052638:Particulate Matter / Q000032:analysis; D018570:Risk Assessment; D012621:Seasons; D055815:Young Adult
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D009585:Nitrogen Dioxide