Work-related Asthma

Note: This publication has been superseded by


The wealth of published articles on occupational asthma (OA) can make assessing the state of prevention research challenging. This primer describes and summarizes current literature, and highlights some of the areas where work is still needed.

OA is defined as a reversible, generalized airway narrowing as a result of exposure to airborne dust, gases, vapors, or fumes in the work environment.(1) A recent Statement of the American Thoracic Society estimated that approximately 15% of asthma in the adult population is attributable to occupational exposure,(2) although other estimates have ranged from 5% to 37%.(3), (4) A substantial amount of information exists on particular agents or conditions known to cause OA, for which relevant preventive measures have taken place. Recent reviews of OA in the literature have cited hallmark studies that document successful intervention efforts, most notably for health care workers using natural rubber latex (NRL) gloves, laboratory animal handlers, and workers in the detergent industry.(5),(6) In addition, the recent reviews sound the call for more studies that better evaluate the effectiveness of OA prevention efforts.

Prevention is not a single entity, and it is often divided into three categories: primary, secondary, and tertiary prevention.

“Primary prevention is [the] protection of health by personal and communal efforts, such as enhancing nutritional status, immunizing against communicable diseases, and eliminating environmental risks, such as contaminated water supplies.” (7)
Stage: susceptibility (8)

“Secondary prevention is [the] set of measures available to individuals and communities for the early detection and prompt intervention to control disease and minimize disability, e.g., by the use of screening programs.” (7)
Stage: early disease, i.e. pre-clinical and clinical stages (8)

“Tertiary prevention consists of measures aimed at softening the impact of long-term disease and disability by eliminating or reducing impairment, disability and handicap; minimizing suffering; and maximizing potential years or useful life” (7)
Stage: advanced disease or disability (8)

Primary prevention of OA means eliminating or controlling the exposure of interest. For OA, primary prevention may include the use of measures such as pre-employment screening, designed to minimize the proportion of susceptible people among workers. (9;10) While elimination of the sensitizing agent is the ideal intervention, reduction of exposure to the agent, use of personal protective equipment (e.g., respirators), and limiting the number of people exposed to the agent should be considered if elimination is not possible.

Secondary prevention aims to reduce disease prevalence by shortening the duration of disease. (11) Routine medical screening for the initial symptoms and signs of asthma in workers is one component of secondary prevention used to guide early intervention that effectively slows or stops disease progression. Many workers will react to minute quantities of the offending agent once they become sensitized. It is generally accepted then that early identification of OA and removing the worker from exposure will result in a good outcome, provided that the worker has had symptoms for less than 1 year and has relatively normal pulmonary function values.(10) However, other occupational options and economic costs for the worker must also be considered. Finally, tertiary prevention aims at the maximum possible prevention of permanent damage. Pharmaceutical treatment including inhaled corticosteroids and bronchodilators are common measures for tertiary prevention.

Page last reviewed: March 5, 2014