title: Short-term fluctuations in personal black carbon exposure are associated with rapid changes in carotid arterial stiffening.
abstract: BACKGROUND
  Vascular changes may underpin the association between airborne black carbon (BC) and cardiovascular events. Accurate assessment of personal exposure is a major challenge in epidemiological research. BC concentrations are strongly related to time-activity patterns, which is particularly relevant when investigating short-term effects. We investigated associations between arterial stiffness and personal short-term BC exposure.
  
  
  METHODS
  This panel study included 54 healthy adults (92% women, mean age 40.7years). BC exposure was monitored individually with a micro-aethalometer during one workweek. Functional and structural properties of the carotid artery were examined ultrasonographically on two separate days. The effect of different short-term personal BC exposure windows (1, 2, 4, 6, 8, 24 and 48h before the ultrasound examination) on carotid artery stiffness was estimated using mixed models while adjusting for other known correlates of arterial stiffness.
  
  
  RESULTS
  Median personal BC exposures within the same day ranged from 599.8 to 728.9ng/m(3) and were associated with carotid arterial stiffness measures. Young's elastic modulus and pulse wave velocity, both measures of stiffness, were positively associated with BC exposure, while the distensibility and compliance coefficient, measures of elasticity, were negatively associated with BC exposure. The strongest associations were observed with BC exposure 8h before the clinical examination. For each 100ng/m(3) increase in exposure within this time window, Young's elastic modulus increased by 2.38% (95% CI: 0.81 to 3.97; P=0.0033), while the distensibility coefficient decreased by 2.27% (95% CI: -3.62 to -0.92; P=0.0008).
  
  
  CONCLUSIONS
  Short-term elevations in personal BC exposure, even within hours, are associated with increased arterial stiffness. This response may reflect a pathway by which air pollution triggers cardiovascular events.
authors.affiliation: Centre for Environmental Sciences, Hasselt University (UHasselt), Diepenbeek, Belgium; Environmental Risk and Health, Flemish Institute for Technological Research (VITO), Mol, Belgium.
authors.forename: Eline B
authors.initials: EB
authors.lastname: Provost
authors.affiliation: Centre for Environmental Sciences, Hasselt University (UHasselt), Diepenbeek, Belgium; Environmental Risk and Health, Flemish Institute for Technological Research (VITO), Mol, Belgium.
authors.forename: Tijs
authors.initials: T
authors.lastname: Louwies
authors.affiliation: Centre for Environmental Sciences, Hasselt University (UHasselt), Diepenbeek, Belgium.
authors.forename: Bianca
authors.initials: B
authors.lastname: Cox
authors.affiliation: Centre for Environmental Sciences, Hasselt University (UHasselt), Diepenbeek, Belgium; Department of Internal Medicine, Maastricht University Medical Centre (MUMC+), Maastricht, The Netherlands.
authors.forename: Jos
authors.initials: J
authors.lastname: Op 't Roodt
authors.affiliation: Interuniversity Institute for Biostatistics and statistical Bioinformatics, Hasselt University (UHasselt), Diepenbeek, Belgium.
authors.forename: Francesca
authors.initials: F
authors.lastname: Solmi
authors.affiliation: Centre for Environmental Sciences, Hasselt University (UHasselt), Diepenbeek, Belgium; Environmental Risk and Health, Flemish Institute for Technological Research (VITO), Mol, Belgium.
authors.forename: Evi
authors.initials: E
authors.lastname: Dons
authors.affiliation: Centre for Environmental Sciences, Hasselt University (UHasselt), Diepenbeek, Belgium; School for Mobility, Hasselt University (UHasselt), Diepenbeek, Belgium.
authors.forename: Luc
authors.initials: L
authors.lastname: Int Panis
authors.affiliation: Centre for Environmental Sciences, Hasselt University (UHasselt), Diepenbeek, Belgium; Environmental Risk and Health, Flemish Institute for Technological Research (VITO), Mol, Belgium. Electronic address: patrick.deboever@vito.be.
authors.forename: Patrick
authors.initials: P
authors.lastname: De Boever
authors.affiliation: Centre for Environmental Sciences, Hasselt University (UHasselt), Diepenbeek, Belgium; Department of Public Health & Primary Care, Leuven University (KU Leuven), Leuven, Belgium.
authors.forename: Tim S
authors.initials: TS
authors.lastname: Nawrot
mesh_terms: D000328:Adult; D000393:Air Pollutants / Q000032:analysis*; D001530:Belgium; D002339:Carotid Arteries / Q000187:drug effects*; D055119:Elastic Modulus; D004781:Environmental Exposure; D004784:Environmental Monitoring; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D063177:Pulse Wave Analysis; D053260:Soot / Q000032:analysis*; D059289:Vascular Stiffness / Q000187:drug effects*; D055815:Young Adult
chemical_list: D000393:Air Pollutants; D053260:Soot
keywords: Air pollution exposure; Arterial stiffness; Black carbon; Carotid artery; Epidemiology