title: Air pollution, ethnicity and telomere length in east London schoolchildren: An observational study.
abstract: Short telomeres are associated with chronic disease and early mortality. Recent studies in adults suggest an association between telomere length and exposure to particulate matter, and that ethnicity may modify the relationship. However associations in children are unknown.
  
  
  
  We examined associations between air pollution and telomere length in an ethnically diverse group of children exposed to high levels of traffic derived pollutants, particularly diesel exhaust, and to environmental tobacco smoke.
  
  
  
  Oral DNA from 333 children (8-9years) participating in a study on air quality and respiratory health in 23 inner city London schools was analysed for relative telomere length using monochrome multiplex qPCR. Annual, weekly and daily exposures to nitrogen oxides and particulate matter were obtained from urban dispersion models (2008-10) and tobacco smoke by urinary cotinine. Ethnicity was assessed by self-report and continental ancestry by analysis of 28 random genomic markers. We used linear mixed effects models to examine associations with telomere length.
  
  
  
  Telomere length increased with increasing annual exposure to NOx(model coefficient 0.003, [0.001, 0.005], p<0.001), NO2(0.009 [0.004, 0.015], p<0.001), PM2.5(0.041, [0.020, 0.063], p<0.001) and PM10(0.096, [0.044, 0.149], p<0.001). There was no association with environmental tobacco smoke. Telomere length was increased in children reporting black ethnicity (22% [95% CI 10%, 36%], p<0.001) CONCLUSIONS: Pollution exposure is associated with longer telomeres in children and genetic ancestry is an important determinant of telomere length. Further studies should investigate both short and long-term associations between pollutant exposure and telomeres in childhood and assess underlying mechanisms.
authors: Asthma UK Centre for Applied Asthma Research, Centre for Primary Care and Public Health, Blizard Institute, Queen Mary University of London, London, United Kingdom. Electronic address: r.walton@qmul.ac.uk.
authors: Robert T
authors: RT
authors: Walton
authors: MRC-PHE Centre for Environment and Health and NIHR HPRU in Health Impact of Environmental Hazards, King's College London, London, United Kingdom.
authors: Ian S
authors: IS
authors: Mudway
authors: Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom.
authors: Isobel
authors: I
authors: Dundas
authors: Asthma UK Centre for Applied Asthma Research, Centre for Primary Care and Public Health, Blizard Institute, Queen Mary University of London, London, United Kingdom.
authors: Nadine
authors: N
authors: Marlin
authors: Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom.
authors: Lee C
authors: LC
authors: Koh
authors: MRC-PHE Centre for Environment and Health and NIHR HPRU in Health Impact of Environmental Hazards, King's College London, London, United Kingdom.
authors: Layla
authors: L
authors: Aitlhadj
authors: Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom.
authors: Tom
authors: T
authors: Vulliamy
authors: MRC-PHE Centre for Environment and Health and NIHR HPRU in Health Impact of Environmental Hazards, King's College London, London, United Kingdom.
authors: Jeenath B
authors: JB
authors: Jamaludin
authors: MRC-PHE Centre for Environment and Health and NIHR HPRU in Health Impact of Environmental Hazards, King's College London, London, United Kingdom.
authors: Helen E
authors: HE
authors: Wood
authors: MRC-PHE Centre for Environment and Health and NIHR HPRU in Health Impact of Environmental Hazards, King's College London, London, United Kingdom.
authors: Ben M
authors: BM
authors: Barratt
authors: MRC-PHE Centre for Environment and Health and NIHR HPRU in Health Impact of Environmental Hazards, King's College London, London, United Kingdom.
authors: Sean
authors: S
authors: Beevers
authors: MRC-PHE Centre for Environment and Health and NIHR HPRU in Health Impact of Environmental Hazards, King's College London, London, United Kingdom.
authors: David
authors: D
authors: Dajnak
authors: Usher Institute of Population Health Sciences and Informatics, The University of Edinburgh, Medical School Doorway 3, Teviot Place, Edinburgh, United Kingdom.
authors: Aziz
authors: A
authors: Sheikh
authors: MRC-PHE Centre for Environment and Health and NIHR HPRU in Health Impact of Environmental Hazards, King's College London, London, United Kingdom.
authors: Frank J
authors: FJ
authors: Kelly
authors: Asthma UK Centre for Applied Asthma Research, Centre for Primary Care and Public Health, Blizard Institute, Queen Mary University of London, London, United Kingdom.
authors: Chris J
authors: CJ
authors: Griffiths
authors: Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, United Kingdom.
authors: Jonathan
authors: J
authors: Grigg
mesh_terms: D000393:Air Pollutants / Q000032:analysis / Q000633:toxicity; D000397:Air Pollution / Q000009:adverse effects* / Q000032:analysis; D002648:Child; D005006:Ethnicity / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D016014:Linear Models; D008131:London; D008297:Male; D009589:Nitrogen Oxides / Q000009:adverse effects; D052638:Particulate Matter / Q000009:adverse effects; D016615:Telomere / Q000187:drug effects*; D059505:Telomere Homeostasis / Q000187:drug effects* / Q000235:genetics; D014028:Tobacco Smoke Pollution / Q000009:adverse effects / Q000032:analysis; D001335:Vehicle Emissions / Q000032:analysis / Q000633:toxicity*
chemical_list: D000393:Air Pollutants; D009589:Nitrogen Oxides; D052638:Particulate Matter; D014028:Tobacco Smoke Pollution; D001335:Vehicle Emissions
keywords: Air pollution; Ethnicity; Lung function; Nitrogen oxides; Particulate matter; Telomeres