For people exposed to World Trade Center site, lung function improves with time

Led by Dr Joan Reibman of New York University School of Medicine, the researchers analyzed the results of repeated lung function tests in 946 individuals exposed to the WTC site during and/or after the attacks. The patients were followed up at the Bellevue Hospital Center WTC Environmental Health Center.

At first evaluation, the patients had a "restrictive" pattern of lung function abnormalities typical of WTC exposure. About 86 percent had breathing-related symptoms after being exposed to the WTC attacks and/or cleanup. The analysis included an average of three lung function tests (spirometry) performed up to six years apart.

The results showed a pattern of improvement on repeated spirometry tests. Two key measures reflecting the ability to exhale air from the lungs -- forced vital capacity and forced expiratory volume in one second -- increased by an average of one percent per year or more.

Groups with different exposure characteristics had different patterns of improvement. Rescue and recovery workers had greater improvement in lung function, while local workers (people who worked near the WTC site) had the least improvement. Despite the gains, however, lung function measures remained below normal in all groups, of WTC-exposed patients. Heavy smokers -- who accounted for about one-fifth of the patients -- had no long-term improvement in lung function.

"These data demonstrate spirometry improvement in select populations suggesting reversibility in airway injury and reinforcing the importance of continued treatment," the researchers write. They suggest that similar long-term evaluation and follow-up may be needed for people exposed to other environmental disasters.