Occupational asthma is defined as a variable airway narrowing related to exposure in the working environment to airborne dusts, gases, vapors, or fumes. Occupational asthma affects a diverse group of people ranging from bakers to chemical workers. Research has identified more than 200 causal agents such as organophosphates, formalin, diisocyanates, platinum salts, and wood dusts.
Limited work has been performed on how much adult asthma can be attributed to work. A study from Japan found that in 15 percent of adult asthmatics, their asthma was caused by their occupation. However, the Japanese industries associated with occupational asthma are different from those found in the United States. For example, in Japan, occupational asthma was reported in the sericulture (silk production) industry and the manufacture of Maiko, which is used in the production of some Japanese foods. A survey of patients receiving Social Security disability for asthma in the United States also attributed 15 percent of asthma to work exposures. Patients in this study were considered to have occupational asthma if they felt that the cause of their asthma was related to the workplace. Data were not available to evaluate the patients self-reported assessment of cause. Finally, a national committee of pulmonary experts estimated that 2 percent of asthma in adults was caused by work exposures. A study was not conducted to derive this estimate.
There are approximately 11,000 adults discharged each year from Michigan hospitals with the diagnosis of asthma. Adult asthmatics discharged from three hospitals were interviewed to provide an estimate of how much asthma could be attributed to work exposures.
The patients in this study were discharged from one of three Michigan hospitals in 1990 with a primary diagnosis of asthma. The three hospitals were contacted in the spring of 1991 and asked to identify patients with a primary discharge diagnosis of ICD-493. The hospitals complied by sending the following data: name of patient, age of patient, gender, address, and phone number. Three large urban hospitals geographically separated were selected. These hospitals are hospital A (294 beds) in Detroit, hospital В (540 beds) in Flint, and hospital С (285 beds) in Lansing.