Exposure to substances in the workplace and new-onset asthma: an international prospective population-based study (ECRHS-II).
BACKGROUND
The role of exposure to substances in the workplace in new-onset asthma is not well characterised in population-based studies. We therefore aimed to estimate the relative and attributable risks of new-onset asthma in relation to occupations, work-related exposures, and inhalation accidents.


METHODS
We studied prospectively 6837 participants from 13 countries who previously took part in the European Community Respiratory Health Survey (1990-95) and did not report respiratory symptoms or a history of asthma at the time of the first study. Asthma was assessed by methacholine challenge test and by questionnaire data on asthma symptoms. Exposures were defined by high-risk occupations, an asthma-specific job exposure matrix with additional expert judgment, and through self-report of acute inhalation events. Relative risks for new onset asthma were calculated with log-binomial models adjusted for age, sex, smoking, and study centre.


RESULTS
A significant excess asthma risk was seen after exposure to substances known to cause occupational asthma (Relative risk=1.6, 95% CI 1.1-2.3, p=0.017). Risks were highest for asthma defined by bronchial hyper-reactivity in addition to symptoms (2.4, 1.3-4.6, p=0.008). Of common occupations, a significant excess risk of asthma was seen for nursing (2.2, 1.3-4.0, p=0.007). Asthma risk was also increased in participants who reported an acute symptomatic inhalation event such as fire, mixing cleaning products, or chemical spills (RR=3.3, 95% CI 1.0-11.1, p=0.051). The population-attributable risk for adult asthma due to occupational exposures ranged from 10% to 25%, equivalent to an incidence of new-onset occupational asthma of 250-300 cases per million people per year.


CONCLUSIONS
Occupational exposures account for a substantial proportion of adult asthma incidence. The increased risk of asthma after inhalation accidents suggests that workers who have such accidents should be monitored closely.
Centre for Research in Environmental Epidemiology, Municipal Institute of Medical Research, Barcelona, Spain. kogevinas@imim.es
Manolis
M
Kogevinas
Jan-Paul
JP
Zock
Debbie
D
Jarvis
Hans
H
Kromhout
Linnéa
L
Lillienberg
Estel
E
Plana
Katja
K
Radon
Kjell
K
Torén
Ada
A
Alliksoo
Geza
G
Benke
Paul D
PD
Blanc
Anna
A
Dahlman-Hoglund
Angelo
A
D'Errico
Michel
M
Héry
Susan
S
Kennedy
Nino
N
Kunzli
Bénédicte
B
Leynaert
Maria C
MC
Mirabelli
Nerea
N
Muniozguren
Dan
D
Norbäck
Mario
M
Olivieri
Félix
F
Payo
Simona
S
Villani
Marc
M
van Sprundel
Isabel
I
Urrutia
Gunilla
G
Wieslander
Jordi
J
Sunyer
Josep M
JM
Antó
D000328:Adult; D001249:Asthma / Q000175:diagnosis / Q000209:etiology*; D016085:Bronchoconstrictor Agents; D005260:Female; D006801:Humans; D008297:Male; D016210:Methacholine Chloride; D016273:Occupational Exposure / Q000009:adverse effects*; D009790:Occupations; D011159:Population Surveillance / Q000379:methods*; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects
D016085:Bronchoconstrictor Agents; D016210:Methacholine Chloride