Occupational exposure to inhalative irritants and methacholine responsiveness.
OBJECTIVE
Occupational exposures to inhalative irritants have been associated with an increased reporting of respiratory symptoms in previous studies. Methacholine responsiveness represents a continuous measure of airway responsiveness. As such, it may be less subject to recall bias and more sensitive to detecting effects of occupational exposure on airways. Such effects may be stronger among atopic persons. The objective of the study was to examine the relationship between self-reports of occupational exposure to dusts, gases, vapors, aerosols, and fumes and methacholine responsiveness.


METHODS
A sample was studied of never smokers (N=3044) chosen randomly from 8 areas in Switzerland. Atopy was defined as any positive skin test to 8 inhalative allergens. Nonspecific bronchial reactivity was tested using methacholine chloride and quantified by calculating the slope of the dose-response.


RESULTS
The methacholine slopes were 19% [95% confidence interval (95% CI) 6-32] higher for never smokers with exposure to dusts, fumes, vapors, gases, or aerosols than for the unexposed group. When only atopic never smokers were examined. the increase was larger (37%, 95% CI 7-75), and for persons with >2 positive skin prick tests the effect was still higher (42%, 95% CI -1.5-104). Exposure to vapors and aerosols was strongly associated with increased methacholine slopes among the atopic subjects.


CONCLUSIONS
Occupational exposure, particularly to dusts and fumes, was associated with increased bronchial reactivity in never smokers in this study. The magnitude of the effect was larger among atopic subjects.
Leuenberger
P
P
Department of Internal Medicine, University Hospital Lausanne, Switzerland. philippe.leuenberger@chuv.hosped.ch
Schindler
C
C
Schwartz
J
J
Ackermann-Liebrich
U
U
Tara
D
D
Perruchoud
A P
AP
Wüthrich
B
B
Zellweger
J P
JP
Blaser
K
K
Bolognini
G
G
Bongard
J P
JP
Brändli
O
O
Domenighetti
G
G
Elsasser
S
S
Grizé
L
L
Karrer
W
W
Keller
R
R
Künzli
N
N
Medici
T
T
Schöni
M H
MH
Solari
G
G
Tschopp
J M
JM
Villiger
B
B
Zemp
E
E
D000293:Adolescent; D000328:Adult; D000395:Air Pollutants, Occupational / Q000009:adverse effects; D016535:Bronchial Hyperreactivity / Q000175:diagnosis* / Q000453:epidemiology / Q000276:immunology; D001985:Bronchial Provocation Tests; D016085:Bronchoconstrictor Agents; D016001:Confidence Intervals; D004784:Environmental Monitoring / Q000379:methods* / Q000706:statistics & numerical data; D062665:Epidemiological Monitoring; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D015994:Incidence; D007509:Irritants / Q000009:adverse effects* / Q000276:immunology; D008297:Male; D016210:Methacholine Chloride; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects*; D010328:Patch Tests; D010358:Patient Participation; D012016:Reference Values; D012307:Risk Factors; D012494:Sampling Studies; D012907:Smoking / Q000009:adverse effects / Q000453:epidemiology; D013557:Switzerland / Q000453:epidemiology
D000395:Air Pollutants, Occupational; D016085:Bronchoconstrictor Agents; D007509:Irritants; D016210:Methacholine Chloride