title: Intervention to lower household wood smoke exposure in Guatemala reduces ST-segment depression on electrocardiograms.
abstract: BACKGROUND
  A large body of evidence suggests that fine particulate matter (PM) air pollution is a cause of cardiovascular disease, but little is known in particular about the cardiovascular effects of indoor air pollution from household use of solid fuels in developing countries. RESPIRE (Randomized Exposure Study of Pollution Indoors and Respiratory Effects) was a randomized trial of a chimney woodstove that reduces wood smoke exposure.
  
  
  OBJECTIVE
  We tested the hypotheses that the stove intervention, compared with open fire use, would reduce ST-segment depression and increase heart rate variability (HRV).
  
  
  METHODS
  We used two complementary study designs: a) between-groups comparisons based on randomized stove assignment, and b) before-and-after comparisons within control subjects who used open fires during the trial and received chimney stoves after the trial. Electrocardiogram sessions that lasted 20 hr were repeated up to three times among 49 intervention and 70 control women 38-84 years of age, and 55 control subjects were also assessed after receiving stoves. HRV and ST-segment values were assessed for each 30-min period. ST-segment depression was defined as an average value below -1.00 mm. Personal fine PM [aerodynamic diameter ≤ 2.5 μm (PM₂.₅] exposures were measured for 24 hr before each electrocardiogram.
  
  
  RESULTS
  PM₂.₅ exposure means were 266 and 102 μg/m³ during the trial period in the control and intervention groups, respectively. During the trial, the stove intervention was associated with an odds ratio of 0.26 (95% confidence interval, 0.08-0.90) for ST-segment depression. We found similar associations with the before-and-after comparison. The intervention was not significantly associated with HRV.
  
  
  CONCLUSIONS
  The stove intervention was associated with reduced occurrence of nonspecific ST-segment depression, suggesting that household wood smoke exposures affect ventricular repolarization and potentially cardiovascular health.
authors.affiliation: Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts, USA. jmccrack@hsph.harvard.edu
authors.forename: John
authors.initials: J
authors.lastname: McCracken
authors.forename: Kirk R
authors.initials: KR
authors.lastname: Smith
authors.forename: Peter
authors.initials: P
authors.lastname: Stone
authors.forename: Anaité
authors.initials: A
authors.lastname: Díaz
authors.forename: Byron
authors.initials: B
authors.lastname: Arana
authors.forename: Joel
authors.initials: J
authors.lastname: Schwartz
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000393:Air Pollutants / Q000032:analysis / Q000633:toxicity*; D016902:Air Pollution, Indoor / Q000517:prevention & control*; D001145:Arrhythmias, Cardiac / Q000139:chemically induced / Q000453:epidemiology* / Q000517:prevention & control*; D003296:Cooking / Q000295:instrumentation*; D015716:Electrocardiography, Ambulatory; D005260:Female; D006166:Guatemala / Q000453:epidemiology; D006339:Heart Rate; D006801:Humans; D019570:Inhalation Exposure / Q000517:prevention & control*; D008875:Middle Aged; D052638:Particulate Matter / Q000032:analysis / Q000633:toxicity; D012906:Smoke / Q000009:adverse effects / Q000517:prevention & control; D014934:Wood / Q000633:toxicity
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D012906:Smoke