1. Occupational exposures and risk of chronic obstructive pulmonary disease (COPD)
Kjell Torén
Section of Occupational and environmental medicine
University of Gothenburg and Sahlgrenska University Hospital
Gothenburg
SWEDEN

3. Kjuus et al, 1981 Hospital-based case-control study
36 cases with emphysema
72 controls matched for smoking and age
Air pollution at workplace>10 år
Relative risk 4.1 ( )

4. Welding

5. Miners

6. Other early studies
Fletcher C. AMA Arch Ind Health 1958;18:
”Men who work in dusty trades, especially coal miners, have a higher prevalence of symptoms of bronchitis and emphysema….”

8. Oxman AD et al.
Occupational dust exposure and chronic obstructive pulmonary disease. A systematic overview of the evidence.
Am Rev Respir Dis 1993;148:38-48

9. Oxman, AD et al, 1993
Smoking miners who had worked more then 30 yrs in a dusty work-place showed a three-fold increased risk to developd emphysema compared to those smoking miners not working in a dusty environment.

10. Oxman, AD et al, 1993
Few cohorts
Heavily exposed
But – changed our thinking about occupation and COPD

12. To elucidate whether different definitions of COPD affect the risk estimates
To investigate the relation between occupational exposures
and CT-confirmed emphysema

13. General population based study
Gothenburg, Sweden
1,050 subjects aged 50 to 64 years
Spirometry before and after bronchodilation
Local reference values for LLN
Extensive questionnaires
Logistic regression modeling

14. Definitions
Airway obstruction; FEV1/VC<0.7 (before bronchodilation)
COPD (GOLD); FEV1/VC<0.7 (after bronchodilation)
COPD (LLN); FEV1/VC<below LLN (after bronchodilation)
Physician-diagnosed COPD; Have you ever had COPD diagnosed by a physician?

15. The extent of emphysema was visually estimated on a four point scale (absent, mild, moderate or severe) in the three zones of each lung.
All subjects with mild emphysema in any zone were categorized as having emphysema.
Chronic bronchitis; Have you had longstanding cough with phlegm? and If so, did any period last at least three months? and If so have you had such periods at least two years in a row?

16. Occupational exposure based on three items; “Have you ever been exposed at your workplace for vapor, gas, dust or fumes?”; “Have you in your work been exposed to diesel exhaust?” and “Have you in your work been exposed to welding fumes or metal fumes?”
Two exposure groups were defined;
1. VGDF; Exposure to vapor, gases, dusts or fumes.
2. Welding/diesel; Exposure to either VGDF or welding/metal fumes or diesel exhaust

17. Current VGDF Welding/ smoking diesel
Airway obstruction
(n=212)
COPD (GOLD)
(n=173)
COPD(LLN)
(n=164)
Emphysema
(n=98)

18. Current VGDF Welding/ smoking diesel
Physician-diagnosed
COPD
(n=25)
Chronic bronchitis
(n=76)

19. Conclusions;
No difference in riskestimates between the GOLD or LLN approach
Higher risks when using prebronchodilatory values
High risk when using physician-diagnosed COPD.
Bias?
Matter of specificity?
CT-defined emphysema was associated with increased risk due to occupational exposures