RETRO: "Retrospective analysis of chamber studies data"

A cooperation project between Helmholtz Zentrum München – Institute of Epidemiology II and U.S. Environmental Protection Agency (Environmental Public Health Division, Chapel Hill, North Carolina)

Study objective:
The primary hypothesis of the study is: Increases in ambient air pollutants lead to altered cardiac autonomic balance in young and healthy subjects and in subjects with metabolic syndrome or mild asthma.
The secondary hypotheses are: Exposure of these subjects to ambient air pollutants results in changes in blood parameters of inflammation and coagulation as well as in an altered lung function.

Specific aims:
Determine the association between fine particulate matter (PM2.5) and ozone and changes in health effect parameters which provide information about responses by the cardiac and autonomic nervous system as well as by lung function and hematologic system. These include changes in:

  • heart rate variability, complexity of ectopic heart beats, T wave measures and measures of repolarization
  • serum levels of pro-inflammatory proteins, coagulation proteins and acute phase reactants
  • peripheral blood red cell and white cell indices
  • parameters of lung function assessed by spirometry

Study design:

Combination of existing chamber studies using only the repeated health measurements pre and 24h post air exposure in the chamber.

Study population:
Healthy and young participants as well as participants with metabolic syndrome or mild asthma from different studies.

Study area:
Chapel-Hill/Durham/Raleigh area, North Carolina, USA;
Clinical exam site: Environmental Public Health Division (EPHD) of Environmental Protection Agency (EPA) in Chapel Hill, North Carolina, USA.

Study methods:
Exposure assessment:

  • Daily 24-hour concentrations of official ambient PM2.5 mass network data (particles with aerodynamique diameter < 2.5 µm) are obtained from an official monitoring station located approximately 44 km (27 miles) east of the EPHD.
  • 1-hour concentrations of ozone are obtained from an official monitoring station located approximately 44 km (27 miles) east of the EPHD.
  • Daily 24-hour concentrations (midnight – midnight) of air temperature and relative humidity are obtained from the measurement station located at the Chapel Hill Williams Airport.

Health outcome:
Health assessment via clinical examinations include:

  • Interview
  • Short- and long-term ECG
  • Blood withdrawal
  • Spirometry

Statistical methods:

Mixed models with random patient intercept.

Study period:
2012 - ongoing

Current status:
Data management ongoing. More data of other chamber studies will be included in the future.

Environmental Protection Agency – Human Studies Division: Robert B. Devlin (PI);
University of North Carolina, School of Medicine, Chapel Hill, North Carolina: Alan
Hinderliter (Co-PI) and John Buse (Co-PI).

The study is funded by a contract between the U.S. Environmental Protection Agency (EPA) and Dr. Alexandra Schneider for data management, analysis and manuscript preparation.

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