title: Effects of profession on urinary PAH metabolite levels in the US population.
abstract: OBJECTIVE
  Although exposure to polycyclic aromatic hydrocarbons (PAHs) is common in both environmental and occupational settings, few studies have compared PAH exposure among people with different professions. The purpose of this study was to investigate the variations in recent PAH exposure among different occupational groups over time using national representative samples.
  
  
  METHODS
  The study population consisted of 4162 participants from the 2001 to 2008 National Health and Nutrition Examination Survey, who had both urinary PAH metabolites and occupational information. Four corresponding monohydroxy-PAH urine metabolites: naphthalene (NAP), fluorene (FLUO), phenanthrene (PHEN), and pyrene (PYR) among seven broad occupational groups were analyzed using weighted linear regression models, adjusting for creatinine levels, sociodemographic factors, smoking status, and sampling season.
  
  
  RESULTS
  The overall geometric mean concentrations of NAP, FLUO, PHEN, and PYR were 6927, 477, 335, and 87 ng/L, respectively. All four PAH metabolites were elevated in the "extractive, construction, and repair (ECR)" group, with 21-42 % higher concentrations than those in the reference group of "management." Similar trends were seen in the "operators, fabricators, and laborers (OFL)" group for FLUO, PHEN, and PYR. In addition, both "service" and "support" groups had elevated FLUO. Significant (p < 0.001) upward temporal trends were seen in NAP and PYR, with an approximately 6-17 % annual increase, and FLUO and PHEN remained relatively stable. Race and socioeconomic status show independent effects on PAH exposure.
  
  
  CONCLUSIONS
  Heterogeneous distributions of urinary PAH metabolites among people with different job categories exist at the population level. The upward temporal trends in NAP and PYR warrant reduction in PAH exposure, especially among those with OFL and ECR occupations.
authors.affiliation: Department of Population Health, Hofstra North Shore-LIJ School of Medicine, 175 Community Drive, Great Neck, NY, 11021, USA. bliu@nshs.edu.
authors.forename: Bian
authors.initials: B
authors.lastname: Liu
authors.affiliation: School of Public Health, University of Memphis, Memphis, TN, 38152, USA.
authors.forename: Chunrong
authors.initials: C
authors.lastname: Jia
mesh_terms: D000293:Adolescent; D000328:Adult; D003430:Cross-Sectional Studies; D005260:Female; D005449:Fluorenes / Q000652:urine; D006801:Humans; D016014:Linear Models; D008297:Male; D009281:Naphthalenes / Q000652:urine; D016273:Occupational Exposure / Q000032:analysis*; D009790:Occupations / Q000706:statistics & numerical data*; D010616:Phenanthrenes / Q000652:urine; D011084:Polycyclic Aromatic Hydrocarbons / Q000652:urine*; D011721:Pyrenes / Q000652:urine; D044469:Racial Groups / Q000706:statistics & numerical data; D012959:Socioeconomic Factors; D013997:Time Factors; D014481:United States / Q000453:epidemiology; D055815:Young Adult
chemical_list: D005449:Fluorenes; D009281:Naphthalenes; D010616:Phenanthrenes; D011084:Polycyclic Aromatic Hydrocarbons; D011721:Pyrenes; C031721:naphthalene; C041509:fluorene; C031181:phenanthrene; C030984:pyrene
keywords: NHANES; Naphthalene; Occupation; PAHs; Pyrene