Higher rate of hospitalization associated with occupational asthma
For the first time, Canadian researchers have shown that workers with occupational asthma are at higher risk for hospitalization, mostly from respiratory disease and asthma, than are other employees who suffered musculoskeletal injury. Using data from 1980 to 1993 from the Ontario Workers Compensation Board, investigators studied 844 workers with occupational asthma,1,556 musculoskeletal injury victims, and 402 asthma patients from an outpatient clinic. They found the rate for hospitalization for all causes was slightly over 39 percent for occupational asthma patients, while it slightly exceeded 29 percent for injury claimants, with asthma clinic patients at 47 percent. The asthma clinic patients were admitted to the hospital for respiratory disease nearly twice as often as those with occupational asthma. The study appears in the July American Journal of Respiratory and Critical Care Medicine.
High rate of clinically silent acid reflux uncovered in asthma
Sixteen of 26 asthma patients, without gastrointestinal reflux symptoms, showed abnormal esophageal acid levels when tested over a 24-hour period. (Acid reflux is a backflow of stomach contents upwards into the esophagus.) The researchers said that the high prevalence (62 percent) in these patients with clinically silent reflux showed that the problem may be commonly associated with asthma. Research has disclosed that identifying and treating reflux, regardless of symptoms, improved asthma control. The 30 clinic patient controls with reflux symptoms had more severe asthma that did those with no symptoms, but the latter had higher amounts of acid in the esophagus. The investigators commented that the role of acid reflux in asthma is very complex and not understood at this time. Their research appears in the July issue of the American Journal of Respiratory and Critical Care Medicine.
Diesel exhaust particles cause airway inflammation
In the first published study of the isolated effects of controlled exposure to tiny diesel exhaust particles in humans, researchers found inhalation of particulate matter caused an inflammatory response in the volunteers. They measured increases in neutrophils (large white blood cells that ingest antigens) in the sputum of eight of the 10 subjects, plus an increased level of hemoprotein, and higher exhaled carbon monoxide levels indicating oxidant stress, following a two-hour exposure to the tiny particles in a test chamber. The participants had no changes in cardiovascular parameters or in lung function. Although the study volunteers did not complain of any adverse effects or symptoms from the exposure, the investigators believe the study gives direct evidence of the important role for diesel exhaust particles in provoking inflammatory response. The research appears in the July issue of the American Journal of Respiratory and Critical Care Medicine.
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Journal
American Journal of Respiratory and Critical Care Medicine