Asthma severity and exposure to occupational asthmogens.
BACKGROUND
Severe asthma is a public health problem with limited information regarding preventable causes. Although occupational exposures have been implicated as important risk factors for asthma and asthma exacerbations, associations between occupational exposures and asthma severity have not been reported.


OBJECTIVE
To examine associations between occupational exposures and asthma severity.


METHODS
The Epidemiological Study on the Genetics and Environment of Asthma combines a case-control study with a family study of relatives of patients with asthma. Adult patients (n = 148) were recruited in chest clinics and control subjects without asthma (n = 228) were population-based. Occupational exposures to nonasthmogenic irritants and asthmogens (classified as "any asthmogen" including three broad groups: high-molecular-weight agents, low-molecular-weight agents, and mixed environments) were assessed by an asthma-specific job exposure matrix. Asthma severity was defined from an 8-grade clinical score (frequency of attacks, persistent symptoms, and hospitalization). Patients with severe (score >or= 2) and mild asthma were compared with control subjects using nominal logistic regression.


RESULTS
Significant associations were observed between severe adult-onset asthma and exposure to any occupational asthmogen (odds ratio [OR], 4.0; 95% confidence interval [CI], 2.0-8.1), high-molecular-weight agents (OR, 3.7; CI, 1.3-11.1), low-molecular-weight agents (OR, 4.4; CI, 1.9-10.1), including industrial cleaning agents (OR, 7.2; CI, 1.3-39.9), and mixed environments (OR, 7.5; CI, 2.4-23.5). No significant associations were found between nonasthmogenic irritants and asthma severity, nor between asthmogens and childhood-onset asthma or mild adult-onset asthma.


CONCLUSIONS
Our results suggested a strong deleterious role of occupational asthmogens in severe asthma. Clinicians should consider occupational exposures in patients with moderate to severe asthma.
Le Moual
Nicole
N
INSERM U472, 16 avenue Paul Vaillant Couturier, 94807 Villejuif Cedex, France. lemoual@vjf.inserm.fr
Siroux
Valérie
V
Pin
Isabelle
I
Kauffmann
Francine
F
Kennedy
Susan M
SM
D000328:Adult; D000395:Air Pollutants, Occupational / Q000009:adverse effects*; D001249:Asthma / Q000139:chemically induced* / Q000175:diagnosis / Q000453:epidemiology; D016022:Case-Control Studies; D003902:Detergents / Q000009:adverse effects; D005260:Female; D006801:Humans; D008297:Male; D008970:Molecular Weight; D009784:Occupational Diseases / Q000139:chemically induced* / Q000175:diagnosis / Q000453:epidemiology; D016273:Occupational Exposure / Q000009:adverse effects; D012307:Risk Factors; D012720:Severity of Illness Index
D000395:Air Pollutants, Occupational; D003902:Detergents