title: Air pollution exposure and telomere length in highly exposed subjects in Beijing, China: a repeated-measure study.
abstract: BACKGROUND
  Ambient particulate matter (PM) exposure has been associated with short- and long-term effects on cardiovascular disease (CVD). Telomere length (TL) is a biomarker of CVD risk that is modified by inflammation and oxidative stress, two key pathways for PM effects. Whether PM exposure modifies TL is largely unexplored.
  
  
  OBJECTIVE
  To investigate effects of PM on blood TL in a highly-exposed population.
  
  
  METHODS
  We measured blood TL in 120 blood samples from truck drivers and 120 blood samples from office workers in Beijing, China. We measured personal PM(2.5) and Elemental Carbon (EC, a tracer of traffic particles) using light-weight monitors. Ambient PM(10) was obtained from local monitoring stations. We used covariate-adjusted regression models to estimate percent changes in TL per an interquartile-range increase in exposure.
  
  
  RESULTS
  Covariate-adjusted TL was higher in drivers (mean=0.87, 95%CI: 0.74; 1.03) than in office workers (mean=0.79, 95%CI: 0.67; 0.93; p=0.001). In all participants combined, TL increased in association with personal PM(2.5) (+5.2%, 95%CI: 1.5; 9.1; p=0.007), personal EC (+4.9%, 95%CI: 1.2; 8.8; p=0.01), and ambient PM(10) (+7.7%, 95%CI: 3.7; 11.9; p<0.001) on examination days. In contrast, average ambient PM(10) over the 14 days before the examinations was significantly associated with shorter TL (-9.9%, 95%CI: -17.6; -1.5; p=0.02).
  
  
  CONCLUSIONS
  Short-term exposure to ambient PM is associated with increased blood TL, consistent with TL roles during acute inflammatory responses. Longer exposures may shorten TL as expected after prolonged pro-oxidant exposures. The observed TL alterations may participate in the biological pathways of short- and long-term PM effects.
authors.affiliation: Department of Preventive Medicine, Feinberg School of Medicine, Northwestern University, 680 N Lake Shore Drive, Chicago, IL 60611, USA. l-hou@northwestern.edu
authors.forename: Lifang
authors.initials: L
authors.lastname: Hou
authors.forename: Sheng
authors.initials: S
authors.lastname: Wang
authors.forename: Chang
authors.initials: C
authors.lastname: Dou
authors.forename: Xiao
authors.initials: X
authors.lastname: Zhang
authors.forename: Yue
authors.initials: Y
authors.lastname: Yu
authors.forename: Yinan
authors.initials: Y
authors.lastname: Zheng
authors.forename: Umakanth
authors.initials: U
authors.lastname: Avula
authors.forename: Mirjam
authors.initials: M
authors.lastname: Hoxha
authors.forename: Anaité
authors.initials: A
authors.lastname: Díaz
authors.forename: John
authors.initials: J
authors.lastname: McCracken
authors.forename: Francesco
authors.initials: F
authors.lastname: Barretta
authors.forename: Barbara
authors.initials: B
authors.lastname: Marinelli
authors.forename: Pier Alberto
authors.initials: PA
authors.lastname: Bertazzi
authors.forename: Joel
authors.initials: J
authors.lastname: Schwartz
authors.forename: Andrea A
authors.initials: AA
authors.lastname: Baccarelli
mesh_terms: D000328:Adult; D000397:Air Pollution / Q000706:statistics & numerical data*; D015415:Biomarkers / Q000097:blood; D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000378:metabolism; D002681:China; D005260:Female; D006801:Humans; D019570:Inhalation Exposure / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D052638:Particulate Matter / Q000032:analysis; D017382:Reactive Oxygen Species / Q000378:metabolism; D016615:Telomere / Q000502:physiology*; D059506:Telomere Shortening / Q000502:physiology*
chemical_list: D015415:Biomarkers; D052638:Particulate Matter; D017382:Reactive Oxygen Species