title: Brachial artery responses to ambient pollution, temperature, and humidity in people with type 2 diabetes: a repeated-measures study.
abstract: BACKGROUND
  Extreme weather and air pollution are associated with increased cardiovascular risk in people with diabetes.
  
  
  OBJECTIVE
  In a population with diabetes, we conducted a novel assessment of vascular brachial artery responses both to ambient pollution and to weather (temperature and water vapor pressure, a measure of humidity).
  
  
  METHODS
  Sixty-four 49- to 85-year-old Boston residents with type 2 diabetes completed up to five study visits (279 repeated measures). Brachial artery diameter (BAD) was measured by ultrasound before and after brachial artery occlusion [i.e., flow-mediated dilation (FMD)] and before and after nitroglycerin-mediated dilation (NMD). Ambient concentrations of fine particulate mass (PM2.5), black carbon (BC), organic carbon (OC), elemental carbon, particle number, and sulfate were measured at our monitoring site; ambient concentrations of carbon monoxide, nitrogen dioxide, and ozone were obtained from state monitors. Particle exposure in the home and during each trip to the clinic (home/trip exposure) was measured continuously and as a 5-day integrated sample. We used linear models with fixed effects for participants, adjusting for date, season, temperature, and water vapor pressure on the day of each visit, to estimate associations between our outcomes and interquartile range increases in exposure.
  
  
  RESULTS
  Baseline BAD was negatively associated with particle pollution, including home/trip-integrated BC (-0.02 mm; 95% CI: -0.04, -0.003, for a 0.28 μg/m3 increase in BC), OC (-0.08 mm; 95% CI: -0.14, -0.03, for a 1.61 μg/m3 increase) as well as PM2.5, 5-day average ambient PM2.5, and BC. BAD was positively associated with ambient temperature and water vapor pressure. However, exposures were not consistently associated with FMD or NMD.
  
  
  CONCLUSIONS
  Brachial artery diameter, a predictor of cardiovascular risk, decreased in association with particle pollution and increased in association with ambient temperature in our study population of adults with type 2 diabetes.
  
  
  BACKGROUND
  Zanobetti A, Luttmann-Gibson H, Horton ES, Cohen A, Coull BA, Hoffmann B, Schwartz JD, Mittleman MA, Li Y, Stone PH, de Souza C, Lamparello B, Koutrakis P, Gold DR. 2014. Brachial artery responses to ambient pollution, temperature, and humidity in people with type 2 diabetes: a repeated-measures study. Environ Health Perspect 122:242-248; http://dx.doi.org/10.1289/ehp.1206136.
authors.affiliation: Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, USA.
authors.forename: Antonella
authors.initials: A
authors.lastname: Zanobetti
authors.forename: Heike
authors.initials: H
authors.lastname: Luttmann-Gibson
authors.forename: Edward S
authors.initials: ES
authors.lastname: Horton
authors.forename: Allison
authors.initials: A
authors.lastname: Cohen
authors.forename: Brent A
authors.initials: BA
authors.lastname: Coull
authors.forename: Barbara
authors.initials: B
authors.lastname: Hoffmann
authors.forename: Joel D
authors.initials: JD
authors.lastname: Schwartz
authors.forename: Murray A
authors.initials: MA
authors.lastname: Mittleman
authors.forename: Yongsheng
authors.initials: Y
authors.lastname: Li
authors.forename: Peter H
authors.initials: PH
authors.lastname: Stone
authors.forename: Celine
authors.initials: C
authors.lastname: de Souza
authors.forename: Brooke
authors.initials: B
authors.lastname: Lamparello
authors.forename: Petros
authors.initials: P
authors.lastname: Koutrakis
authors.forename: Diane R
authors.initials: DR
authors.lastname: Gold
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000393:Air Pollutants / Q000633:toxicity*; D001794:Blood Pressure / Q000187:drug effects*; D001900:Boston; D001916:Brachial Artery / Q000187:drug effects / Q000502:physiology*; D003924:Diabetes Mellitus, Type 2 / Q000503:physiopathology*; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D006813:Humidity; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D012621:Seasons; D013696:Temperature; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology*
chemical_list: D000393:Air Pollutants