Interaction of atopy and smoking on respiratory effects of occupational dust exposure: a general population-based study.
BACKGROUND
For individual exposures, effect modification by atopy or smoking has been reported on the occurrence of occupational airway disease. It is unclear if effect modification can be studied in a general population by an aggregated exposure measure. Assess relationship between airway obstruction and occupational exposure using a job-exposure-matrix (JEM) classifying jobs into 3 broad types of exposure, and test for effect modification by atopy, and smoking.


METHODS
Data from 1,906 subjects were analyzed, all participants of the European Community Respiratory Health Survey. Job titles were categorized by an a priori constructed job exposure matrix into three classes of exposure to respectively organic dust, mineral dust, and gases/ fumes. Relationships were assessed for 'current wheeze', bronchial hyperresponsiveness (BHR), 'current asthma' (wheeze+BHR), and 'chronic bronchitis' (morning phlegm or morning cough), and lung function.


RESULTS
Subjects with organic dust exposure in their work environment more frequently had 'current asthma' (OR 1.48, 95% C.I. 0.95;2.30), and a lower FEV1 (-59 mL, 95% C.I. -114;-4). The relationship was only present in asthmatic workers, and their risk was four-fold greater than in subjects with either atopy or exposure alone. Mineral dust exposure was associated with 'chronic bronchitis' (OR 2.22, 95% C.I. 1.16;4.23) and a lower FEV1/FVC ratio (-1.1%, 95% C.I. -1.8;-0.3). We observed an excess risk in smokers, greater than the separate effects of smoking or mineral dust exposure together.


CONCLUSIONS
Occupational exposure to organic dust is associated with an increased risk of asthma, particularly in atopics. Chronic bronchitis occurs more frequently among individuals exposed to mineral dust, and smoking doubles this risk.
de Meer
Gea
G
Institute for Risk Assessment Science, Div, Environmental & Occupational Health, Utrecht University, P,O, Box 80176, 3508 TD Utrecht, The Netherlands. G.demeer@iras.uu.nl
Kerkhof
Marjan
M
Kromhout
Hans
H
Schouten
Jan P
JP
Heederik
Dick
D
D000328:Adult; D000368:Aged; D000395:Air Pollutants, Occupational / Q000009:adverse effects* / Q000145:classification; D000402:Airway Obstruction / Q000209:etiology; D001249:Asthma / Q000453:epidemiology / Q000209:etiology; D029481:Bronchitis, Chronic / Q000453:epidemiology / Q000209:etiology; D003876:Dermatitis, Atopic / Q000209:etiology; D004391:Dust / Q000032:analysis*; D005060:Europe / Q000453:epidemiology; D005260:Female; D005740:Gases / Q000009:adverse effects / Q000032:analysis; D006306:Health Surveys; D006801:Humans; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects* / Q000032:analysis / Q000706:statistics & numerical data; D012129:Respiratory Function Tests; D012130:Respiratory Hypersensitivity / Q000453:epidemiology / Q000209:etiology*; D012135:Respiratory Sounds / Q000209:etiology; D012307:Risk Factors; D012882:Skin Tests / Q000379:methods; D012907:Smoking / Q000009:adverse effects* / Q000453:epidemiology; D011795:Surveys and Questionnaires
D000395:Air Pollutants, Occupational; D004391:Dust; D005740:Gases