When several demographic and clinical variables (including age, sex, race, atopy, and chronic rhinitis) were controlled, the analysis found that high ECAT exposure significantly correlated with poor asthma control, as measured by a questionnaire, and a high number of exacerbations. No such link existed for patients who had lower ECAT exposures.
In addition, high ECAT exposure and poor asthma control were linked only in patients with a body mass index of at least 30 kg/m2, Dr. Epstein said. Obese patients had a fivefold increased rate of poor asthma control, compared with leaner patients.
The results reported by Dr. Vastardi focused on 17 patients with asthma, 25 patients with seasonal rhinoconjunctivitis, and 3 patients with both conditions who were patients at Lutheran Medical Center in Brooklyn. All patients were at least 18 years old, and all lived within 2 miles of a busy, elevated interstate highway in Brooklyn. The study also included 17 healthy adults without asthma or rhinoconjunctivitis who lived in the same area. The average age of all participants was about 40 years, and about 60% were women.
The 45 patients lived an average of 0.28 miles from the highway, compared with an average of 0.57 miles among the controls, a statistically significant difference, Dr. Vastardi reported. A more focused analysis showed that the 17 patients who had only asthma lived an average of about 0.1 miles from the highway, whereas the 25 patients who had only seasonal rhinoconjunctivitis lived an average of about 0.4 miles from the highway, a distance that was not significantly different from the controls.
"Our results indicate that proximity to a heavily trafficked highway correlated with the presence of asthma in adults, but not with seasonal allergy," she said. The results suggest that vehicle emissions "increase the risk for developing inflammatory lung disease" in adults.
Dr. Epstein and Dr. Vastardi said that they had no disclosures.