Air pollution and ST-segment depression in elderly subjects

Environ Health Perspect. 2005 Jul;113(7):883-7. doi: 10.1289/ehp.7737.


Increased levels of daily ambient particle pollution have been associated with increased risk of cardiovascular morbidity. Black carbon (BC) is a measure of the traffic-related component of particles. We investigated associations between ambient pollution and ST-segment levels in a repeated-measures study including 269 observations on 24 active Boston residents 61-88 years of age, each observed up to 12 times from June through September 1999. The protocol involved continuous Holter electrocardiogram monitoring including 5 min of rest, 5 min of standing, 5 min of exercise outdoors, 5 min of recovery, and 20 cycles of paced breathing. Pollution-associated ST-depression was estimated for a 10th- to 90th-percentile change in BC. We calculated the average ST-segment level, referenced to the P-R isoelectric values, for each portion of the protocol. The mean BC level in the previous 12 hr, and the BC level 5 hr before testing, predicted ST-segment depression in most portions of the protocol, but the effect was strongest in the postexercise periods. During postexercise rest, an elevated BC level was associated with -0.1 mm ST-segment depression (p = 0.02 for 12-hr mean BC; p = 0.001 for 5-hr BC) in continuous models. Elevated BC also predicted increased risk of ST-segment depression > or = 0.5 mm among those with at least one episode of that level of ST-segment depression. Carbon monoxide was not a confounder of this association. ST-segment depression, possibly representing myocardial ischemia or inflammation, is associated with increased exposure to particles whose predominant source is traffic.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Aged
  • Aged, 80 and over
  • Air Pollutants / adverse effects
  • Air Pollutants / analysis
  • Air Pollution / adverse effects*
  • Carbon / adverse effects*
  • Carbon / analysis
  • Carbon Monoxide / adverse effects
  • Carbon Monoxide / analysis
  • Dust / analysis
  • Electrocardiography, Ambulatory*
  • Environmental Monitoring
  • Exercise Test*
  • Female
  • Heart Rate
  • Humans
  • Male
  • Vehicle Emissions / adverse effects*


  • Air Pollutants
  • Dust
  • Vehicle Emissions
  • Carbon
  • Carbon Monoxide