Risks of exposure to occupational asthmogens in atopic and nonatopic asthma: a case-control study in Taiwan.
BACKGROUND
Asthma is often work-related and can be classified as atopic or nonatopic on the basis of its pathogenesis. Few studies have reported an association between exposure to occupational asthmogens and asthma with and without atopy.


OBJECTIVE
We investigated, in adults with asthma, whether occupational exposure to asthmogens influenced the risk of having atopic or nonatopic asthma, and their level of lung function.


METHODS
We recruited 504 hospital-based adults with current asthma, 504 community-based control subjects, and 504 hospital-based control subjects in southern Taiwan. Asthma with atopy was defined as having asthma in combination with an increase in total IgE (≥100 U/ml) or a positive Phadiatop test (≥0.35 Pharmacia arbitrary unit/L) (Pharmacia ImmunoCAP; Pharmacia, Uppsala, Sweden). Occupational exposure to asthmogens was assessed with an asthma-specific job exposure matrix.


RESULTS
We found a significant association between atopic asthma and exposure to high molecular weight asthmogens (adjusted odds ratio [AOR], 4.0; 95% confidence interval [CI], 1.8-8.9). Nonatopic asthma was significantly associated with exposure to low molecular weight asthmogens (AOR, 2.6; 95% CI, 1.6-4.3), including industrial cleaning agents and metal sensitizers. Agriculture was associated with both atopic and nonatopic asthma (AOR, 7.8; 95% CI, 2.8-21.8; and AOR, 4.1; 95% CI, 1.3-13.0, respectively). The ratio of FEV₁ to FVC in the high-risk group was significantly lower than in the no-risk group (P = 0.026) in currently employed patients with asthma.


CONCLUSIONS
In adults with asthma, occupational exposure to high and low molecular weight asthmogens appears to produce differential risks for atopic and nonatopic asthma.
Wang
Tsu-Nai
TN
Department of Public Health, Kaohsiung Medical University, Taiwan.
Lin
Meng-Chih
MC
Wu
Chao-Chien
CC
Leung
Sum-Yee
SY
Huang
Ming-Shyan
MS
Chuang
Hung-Yi
HY
Lee
Chien-Hung
CH
Wu
Deng-Chyang
DC
Ho
Pei-Shan
PS
Ko
Albert Min-Shan
AM
Chang
Po-Ya
PY
Ko
Ying-Chin
YC
D000293:Adolescent; D000328:Adult; D000368:Aged; D000395:Air Pollutants, Occupational / Q000009:adverse effects*; D001249:Asthma / Q000453:epidemiology*; D016022:Case-Control Studies; D015984:Causality; D003876:Dermatitis, Atopic / Q000453:epidemiology; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D008875:Middle Aged; D008970:Molecular Weight; D009784:Occupational Diseases / Q000453:epidemiology* / Q000209:etiology; D016273:Occupational Exposure / Q000009:adverse effects* / Q000706:statistics & numerical data; D016017:Odds Ratio; D012307:Risk Factors; D013624:Taiwan / Q000453:epidemiology; D055815:Young Adult
D000395:Air Pollutants, Occupational