Ascertaining the risk of chronic obstructive pulmonary disease in relation to occupation using a case-control design

Occup Med (Lond). 2003 May;53(3):165-72. doi: 10.1093/occmed/kqg041.


Background: Recent community surveys have reported a risk of chronic obstructive pulmonary disease (COPD) in occupations involving exposure to organic dust and gas/vapour. Aims Our aim was to confirm these results using a case-control design on 131 COPD cases (FEV(1) < 80% of predicted value, minimally reversible with bronchodilators) and 298 controls, selected from registers for patients admitted to our Institute of Occupational Medicine.

Methods: Surrogates of past exposure were occupation, exposure assigned by a job-exposure matrix, and years spent in a given occupation. The odds ratio (OR) and 95% confidence interval (CI) for COPD were calculated using logistic regression models with office workers as the reference.

Results: Age-smoking-adjusted ORs (and CIs) were: 15.1 (3.2-71.6) in farmers; 7.2 (1.3-41.1) in cotton workers; 6.4 (1.6-25.5) in welders; 4.7 (1.3-16.4) in painters; 12.1 (1.3-108) in foundry workers; 6.50 (1.14-37.0) in refractory brick workers; and 3.1 (1.0-9.5) in construction workers. In farmers, cotton workers, welders and painters, the adjusted ORs significantly increased (by 6-9%) for each extra year of work, while in other occupations any such increase was of borderline significance. Adjusted ORs were 3.80 (1.21-12.0), 5.83 (1.82-18.6) and 8.86 (2.29-34.3) in workers exposed to high levels of mineral dust, gas/vapour/fume and biological dust, respectively. Consistent risk estimates were obtained for farmers, textile workers, painters and welders.

Conclusions: Our findings confirm previous epidemiological evidence and are supported by recent observations that cigarette smoke, cotton and organic farm dust contain the same powerful pro-inflammatory agents, and that organic dust and irritant gas induce bronchitis by triggering the same effector molecules as cigarette smoke.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Case-Control Studies
  • Dust*
  • Female
  • Gases / adverse effects*
  • Humans
  • Italy / epidemiology
  • Logistic Models
  • Male
  • Occupational Diseases / epidemiology
  • Occupational Diseases / etiology*
  • Occupational Exposure / adverse effects*
  • Odds Ratio
  • Pulmonary Disease, Chronic Obstructive / epidemiology
  • Pulmonary Disease, Chronic Obstructive / etiology*
  • Risk Factors
  • Smoking / adverse effects


  • Dust
  • Gases