Health Care Workers Incur Occupational Risk for Asthma

Key Point

Occupational exposures among health care workers are important contributors to asthma risk.

Occupational asthma is a well-known peril in several professions, including construction, farming, and those in which isocyanate chemicals are used. Health care workers may also be at increased risk for asthma due to chronic exposure to respiratory irritants, but this hazard has not been thoroughly studied. Researchers reporting in the April 1 American Journal of Respiratory and Critical Care Medicine have therefore performed a large cross-sectional survey of industry-specific asthma prevalence and risk factors in health care settings, as well as symptoms related to bronchial hyperresponsiveness.

In the study population of 3,650 Texas health care workers with active professional licenses, the investigators found a twofold-increased risk of asthma with onset after respondent entry into a health care profession involving instrument cleaning and disinfection, use of general cleaning products on indoor building surfaces, use of powdered latex gloves, or administration of aerosolized medications. Significant associations also were observed between symptoms of bronchial hyperresponsiveness and use of surface cleaners, adhesives, or solvents during patient care; administration of aerosolized medications; and history of acute exposure to a chemical or gas at work.

“We have confirmed associations between asthma and occupational exposures reported previously in health care settings, and we have identified new relationships that should be studied further,” principal study author George L. Delclos, MD, told Pulmonary Reviews. The findings for bronchial hyperresponsiveness in particular were new, noted Dr. Delclos, Associate Professor of Epidemiology and Occupational Medicine at the University of Texas School of Public Health in Houston.

A total of 3,650 completed questionnaires were returned from 941 nurses, 879 respiratory therapists, 968 occupational therapists, and 862 physicians. The questionnaire was developed and validated by Dr. Delclos and coworkers, as reported in an article published last year, for the assessment of asthma symptoms and occupational exposures in health care workers.

In the current survey population, the overall weighted prevalences of asthma and bronchial hyperresponsiveness symptoms were 6.6 and 27.2%, respectively. Specifically, asthma prevalence was 4.2% for physicians, 7.3% for nurses, 5.6% for respiratory therapists, and 4.5% for occupational therapists. The prevalence of bronchial hyperresponsiveness was 18.0% for physicians, 29.2% for nurses, 30.3% for respiratory therapists, and 33.7% for occupational therapists.

In a univariate analysis, factors that raised asthma risk were increasing age, female sex, obesity, atopy, increasing professional seniority, instrument cleaning, use of cleaning products on building surfaces, use of powdered latex gloves from 1992 to 2000 (during which time the use of such gloves markedly increased), administration of aerosolized medications, and application of adhesives/vapors/gases in patient care. “Significant inverse associations were observed for use of adhesives on surfaces and miscellaneous use of adhesives/solvents/gases,” reported the authors.

Most of the variables associated with asthma showed similar associations with bron­chial hyperresponsiveness–related symptoms. “Smoking was not associated with either outcome,” the authors observed.

In a multivariate analysis adjusted for professional seniority, race/ethnicity, obesity, and atopy, factors significantly associated with asthma included instrument cleaning (odds ratio [OR], 2.22), use of cleaning products on building surfaces (OR, 2.02), use of powdered latex gloves between 1992 and 2002 (OR, 2.17), and administration of aerosolized medications (OR, 1.72). As was true in the univariate analysis, there was an inverse association between asthma and miscellaneous use of adhesives/solvents/gases.

Variables that increased the risk of bronchial hyperresponsiveness symptoms were use of cleaning products on building surfaces (OR, 1.63), administration of aerosolized medications (OR, 1.40), use of adhesives/solvents/gases in patient care (OR, 1.65), and exposure to a chemical spill at work (OR, 2.02). “Health care settings present an opportunity for exposure to several respiratory irritants and sensitizers, and our findings indicate that the contribution of occupational exposures to asthma in [health care workers] is not trivial,” concluded the authors.           

—Timothy Begany

Reference
Delclos GL, Arif AA, Aday L, et al. Validation of an asthma questionnaire for use in healthcare workers. Occup Environ Med. 2006;63:173–179.
Delclos GL, Gimeno D, Arif AA, et al. Occupational risk factors and asthma among health care professionals. Am J Respir Crit Care Med. 2007;175:667-675.

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