Multipollutant Mixtures

This report contains two studies, by Drs. Annette Peters and Douglas Dockery. Dr. Peters and her colleagues evaluated the association between nonfatal myocardial infarction (MI) and exposure to particulate matter just prior to the event. She asked 691 patients in hospitals in Augsburg, Germany who survived an MI to provide hourly details about their activities 4 days before MI onset. The investigators used a case-crossover analysis to determine whether exposure to pollutants was associated with onset of MI. Dr. Dockery and colleagues assessed the correlation between short-term increases in ambient concentrations of particulate matter and the risk of possibly life-threatening arrhythmias in patients with implanted cardioverter defibrillators (ICDs). The investigators studied 195 patients from Boston, MA who had either single or dual-chamber ICD's and used logistic regression models to determine whether exposure to air pollutants was associated with arrhythmias.

Dr. Navidi and colleagues at the University of Southern California discussed the development of three sophisticated statistical methods that would improve the estimates of the health effects of air pollution obtained from epidemiologic studies. First, they took a standard case-crossover design and introduced a bidirectional element where control data were obtained both before and after the health event of interest.

High doses of inhaled diesel engine exhaust produce lung tumors in laboratory animals and may cause cancer in humans. Nitropyrenes are products of diesel engine exhaust and can be activated by the body\'s metabolism to form highly reactive products that interact with DNA to form DNA adducts. The adducts can interfere with the normal processes of DNA replication and can lead to genetic mutations that may result in carcinogenesis. Dr.

This document contains two reports by Drs. McCool and Samet and their colleagues who were funded to develop and test methods for measuring ventilation in freely mobile subjects at home or at work. Drs. Dennis McCool and Domyung Paek at the Memorial Hospital in Rhode Island measured ventilation with a body surface displacement (BSD) model. Each subject wore wide elastic bands containing coated wire coils around the chest and abdomen and had special magnets affixed to the breastbone and navel, which yielded data about their breathing patterns, breath frequency, and ventilation. In the second study, Dr. Jonathan Samet and colleagues at Johns Hopkins University wanted to develop methods for estimating ventilation from heart rate for future epidemiologic studies. They used the Heartwatch, a portable, commercial device combining a small transmitter worn on the subject's chest with a wristwatch-style receiver that records heart rate.