title: Sickness response symptoms among healthy volunteers after controlled exposures to diesel exhaust and psychological stress.
abstract: BACKGROUND
  Interactions between acute exposures to environmental chemical contaminants and psychological stress may be important in situations where they are likely to co-occur, ranging in intensity from daily urban living to participation in war. Modification of symptomatic responses by stress may play a role in medically unexplained symptoms attributed to low-level chemical exposures.
  
  
  OBJECTIVE
  We hypothesized that the combination of exposure to diesel exhaust (DE) and acute psychological stress would cause sickness responses in healthy volunteers. Moreover, these responses would be greater in individuals with self-reported prior chemical odor intolerance.
  
  
  METHODS
  One hundred adult subjects underwent 1-hr exposures to diluted DE and clean air control. Half of the subjects performed a public-speaking stressor task during the exposures. Subjects completed questionnaires to determine their Chemical Odor Intolerance Index score. Plasma cortisol, end-tidal carbon dioxide, and the severity of 35 symptoms were measured at time points before and after the exposures.
  
  
  RESULTS
  Subjects exposed to DE demonstrated small but statistically significant increases in severity for several symptom categories, including sickness response and upper respiratory, central nervous system, and total symptoms. The psychological stressor did not increase symptom severity independently or via interaction with DE. Subjects with prior self-reported chemical intolerance had more severe sickness response symptoms from DE.
  
  
  CONCLUSIONS
  These results suggest that exposure to DE can cause acute sickness response symptoms and that these symptoms are also associated with increased levels of self-reported chemical intolerance. The results did not confirm our hypothesis that an acute stressor would increase sickness response symptom severity during the exposure.
authors.affiliation: University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, Environmental and Occupational Health Sciences Institute, Piscataway, New Jersey 08854, USA. laumbach@eohsi.rutgers.edu
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Laumbach
authors.forename: Howard M
authors.initials: HM
authors.lastname: Kipen
authors.forename: Kathie
authors.initials: K
authors.lastname: Kelly-McNeil
authors.forename: Junfeng
authors.initials: J
authors.lastname: Zhang
authors.forename: Lin
authors.initials: L
authors.lastname: Zhang
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Lioy
authors.forename: Pamela
authors.initials: P
authors.lastname: Ohman-Strickland
authors.forename: Jing
authors.initials: J
authors.lastname: Gong
authors.forename: Alexander
authors.initials: A
authors.lastname: Kusnecov
authors.forename: Nancy
authors.initials: N
authors.lastname: Fiedler
mesh_terms: D000328:Adult; D000393:Air Pollutants / Q000032:analysis / Q000633:toxicity*; D002248:Carbon Monoxide / Q000032:analysis / Q000633:toxicity; D004781:Environmental Exposure; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D009515:New Jersey; D009569:Nitric Oxide / Q000032:analysis / Q000633:toxicity; D009585:Nitrogen Dioxide / Q000032:analysis / Q000633:toxicity; D009812:Odorants / Q000032:analysis; D052638:Particulate Matter / Q000032:analysis / Q000633:toxicity; D011569:Psychiatric Status Rating Scales; D013315:Stress, Psychological; D011795:Surveys and Questionnaires; D001335:Vehicle Emissions / Q000032:analysis / Q000633:toxicity*; D055815:Young Adult
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D001335:Vehicle Emissions; D009569:Nitric Oxide; D002248:Carbon Monoxide; D009585:Nitrogen Dioxide