The Burden of Work-related Asthma in Michigan, 1988-2018

Abstract

Rationale: Exposure to a variety of substances in the workplace can cause new-onset asthma or aggravate preexisting asthma, both of which are considered work-related asthma (WRA). Understanding trends in the nature and causes of WRA can assist in the diagnosis and management of adult patients with asthma.Objective: To describe trends over 31 years of WRA surveillance in Michigan.Methods: Michigan law requires reporting of all known or suspected cases of occupational disease. WRA was confirmed by review of a standardized telephone interview and patient medical records. Enforcement inspections at the workplaces of the WRA cases included air monitoring and evaluation for asthma and asthma symptoms among coworkers.Results: The Michigan surveillance program identified 3,634 WRA cases from 1988 to 2018, including nine deaths. The cumulative incidence rate of WRA decreased from 3.5 to 2.0 cases per 100,000 workers. Cases most frequently worked in manufacturing (56%), health care (12%), and education (4%). The cumulative incidence rate of WRA decreased in each of those three industries, while increasing in retail trade and accommodations and food services. The most common exposures to known asthma inducers were to cleaning agents and isocyanates; the percentage exposed to cleaning agents increased from 5% to 20%, and the percentage exposed to isocyanates decreased from 20% to 7%. Fifty-one percent had not applied for workers' compensation benefits. Only 5% of the 571 workplaces where air sampling was performed were above the allowable exposure limit. Fifteen percent (1,622 of 10,493) of coworkers of the index cases reported onset of asthma since beginning to work at the facility or being bothered at work by daily or weekly chest tightness, shortness of breath, or wheezing.Conclusions: The industries and exposures where Michigan adults develop WRA have changed during the past 31 years. The identification of WRA cases, including WRA deaths, underscores the need for continued vigilance to monitor changes in where and how workers are exposed to asthma-causing agents, physician consideration of workplace exposures in new-onset or worsening adult asthma, and adoption of workplace standards that reduce exposure and require workplace medical monitoring to prevent and reduce the morbidity and mortality of WRA.

Keywords: asthma-causing agents; epidemiology; surveillance; work-related asthma; workplace.