title: Effects of ambient air pollution on functional status in patients with chronic congestive heart failure: a repeated-measures study.
abstract: BACKGROUND
  Studies using administrative data report a positive association between ambient air pollution and the risk of hospitalization for congestive heart failure (HF). Circulating levels of B-type natriuretic peptide (BNP) are directly associated with cardiac hemodynamics and symptom severity in patients with HF and, therefore, serves as a marker of functional status. We tested the hypothesis that BNP levels would be positively associated with short-term changes in ambient pollution levels among 28 patients with chronic stable HF and impaired systolic function.
  
  
  METHODS
  BNP was measured in whole blood at 0, 6, and 12 weeks. We used linear mixed models to evaluate the association between fine particulate matter (PM2.5), carbon monoxide, sulfur dioxide, nitrogen dioxide, ozone, and black carbon and log(BNP). Lags of 0 to 3 days were considered in separate models. We calculated the intraclass correlation coefficient and within-subject coefficient of variation as measures of reproducibility.
  
  
  RESULTS
  We found no association between any pollutant and measures of BNP at any lag. For example, a 10 microg/m3 increase in PM2.5 was associated with a 0.8% (95% CI: -16.4, 21.5; p = 0.94) increase in BNP on the same day. The within-subject coefficient of variation was 45% on the natural scale and 9% on the log scale.
  
  
  CONCLUSIONS
  These results suggest that serial BNP measurements are unlikely to be useful in a longitudinal study of air pollution-related acute health effects. The magnitude of expected ambient air pollution health effects appears small in relation to the considerable within-person variability in BNP levels in this population.
authors.affiliation: Cardiovascular Epidemiology Research Unit, Department of Medicine, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA 02215, USA. gwelleni@bidmc.harvard.edu
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Wellenius
authors.forename: Gloria Y
authors.initials: GY
authors.lastname: Yeh
authors.forename: Brent A
authors.initials: BA
authors.lastname: Coull
authors.forename: Helen H
authors.initials: HH
authors.lastname: Suh
authors.forename: Russell S
authors.initials: RS
authors.lastname: Phillips
authors.forename: Murray A
authors.initials: MA
authors.lastname: Mittleman
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000393:Air Pollutants / Q000009:adverse effects*; D015415:Biomarkers / Q000097:blood; D005260:Female; D006333:Heart Failure / Q000097:blood* / Q000503:physiopathology; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood*; D052638:Particulate Matter / Q000009:adverse effects*; D012189:Retrospective Studies; D013318:Stroke Volume / Q000502:physiology
chemical_list: D000393:Air Pollutants; D015415:Biomarkers; D052638:Particulate Matter; D020097:Natriuretic Peptide, Brain