title: Does ambient CO have protective effect for COPD patient?
abstract: BACKGROUND
  Existing studies found paradoxical effects of carbon monoxide (CO) on human health. Carbon monoxide (CO), at high concentrations, is a well-known toxicant, but recent studies suggest that CO at low concentrations may have protective health effects under certain conditions.
  
  
  OBJECTIVE
  To investigate the acute effect of ambient CO on hospital admission for chronic obstructive pulmonary disease (COPD) in Shanghai, China.
  
  
  METHODS
  Daily data on COPD admissions and CO concentrations between 2006 and 2008 were collected. We applied over-dispersed generalized additive Poisson models, adjusted for weather conditions, day of the week and public holidays, long-term and seasonal trends.
  
  
  RESULTS
  During the study period, the average CO concentration was 1.3mg/m(3), well below the international health-based standard. Negative associations were found between ambient CO concentration and daily COPD hospitalization. An interquartile range increase (0.6 mg/m(3)) in CO concentration at lag 3 day corresponded to -2.97% (95% confidence interval: -4.63%, -1.31%) change in COPD hospitalization. The negative associations were robust after adjustment for co-pollutants (PM10, NO2 and SO2). The protective effect of CO appeared to be more evident in the cool season.
  
  
  CONCLUSIONS
  Short-term exposure to CO at low ambient concentration may be associated with reduced risk of COPD hospitalization. Our results may contribute to a comprehensive understanding on the health effects of ambient CO.
authors.affiliation: School of Public Health, Key Lab of Public Health Safety of the Ministry of Education, & Key Lab of Health Technology Assessment of the Ministry of Health, Fudan University, Shanghai, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Cai
authors.affiliation: School of Public Health, Key Lab of Public Health Safety of the Ministry of Education, & Key Lab of Health Technology Assessment of the Ministry of Health, Fudan University, Shanghai, China; Global Health Institute, Fudan University, Shanghai, China; Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Fudan University, Shanghai, China.
authors.forename: Renjie
authors.initials: R
authors.lastname: Chen
authors.affiliation: School of Public Health, Key Lab of Public Health Safety of the Ministry of Education, & Key Lab of Health Technology Assessment of the Ministry of Health, Fudan University, Shanghai, China.
authors.forename: Weibing
authors.initials: W
authors.lastname: Wang
authors.affiliation: Department of Epidemiology, College of Public Health and Health Professions and College of Medicine, University of Florida, Gainesville, FL, USA.
authors.forename: Xiaohui
authors.initials: X
authors.lastname: Xu
authors.affiliation: Department of Epidemiology, College of Public Health and Health Professions and College of Medicine, University of Florida, Gainesville, FL, USA.
authors.forename: Sandie
authors.initials: S
authors.lastname: Ha
authors.affiliation: School of Public Health, Key Lab of Public Health Safety of the Ministry of Education, & Key Lab of Health Technology Assessment of the Ministry of Health, Fudan University, Shanghai, China; Global Health Institute, Fudan University, Shanghai, China; Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention (LAP3), Fudan University, Shanghai, China. Electronic address: haidongkan@gmail.com.
authors.forename: Haidong
authors.initials: H
authors.lastname: Kan
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002248:Carbon Monoxide / Q000032:analysis*; D002681:China; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000517:prevention & control*; D055815:Young Adult
chemical_list: D002248:Carbon Monoxide
keywords: Carbon monoxide; Chronic obstructive pulmonary disease; Time-series models