title: Impaired lung function and lung cancer incidence in a cohort of Swedish construction workers.
abstract: BACKGROUND
  Although impaired lung function in general has been associated with an increased risk of lung cancer, past studies typically have not attempted to investigate separately the obstructive and restrictive components of respiratory impairment. To deal with this question further, data from a large (n = 176 997) cohort of male Swedish construction workers, for whom spirometry measurements before follow-up were available, were analysed.
  
  
  METHODS
  Cancer incidence for 1971-2001 was obtained through linkage with the national cancer registry. Using a modification of the Global Initiative for Chronic Obstructive Lung Disease criteria for chronic obstructive pulmonary disease (COPD), subjects were classified into five categories of lung function: normal, mild COPD, moderate COPD, severe COPD and restrictive lung disease (RLD). Rate ratios (RR) and 95% confidence intervals (CI) for lung cancer across lung function categories were calculated using Poisson regression, adjusted for age and smoking. Other end points (histological types of lung cancer, non-lung tobacco-related cancers, other cancers, total mortality) were also investigated.
  
  
  RESULTS
  834 incident cases of lung cancer were identified. Increased rates of lung cancer were observed for both COPD (mild: RR 1.5, 95% CI 1.2 to 1.9; moderate/severe: RR 2.2, 95% CI 1.8 to 2.7) and RLD (RR 2.0, 95% CI 1.6 to 2.5) relative to normal lung function. These associations did not meaningfully change on applying follow-up lag times of 5, 10 and 15 years after spirometry. When analysed by histological type, associations with both COPD and RLD were stronger for squamous cell carcinoma and small cell carcinoma, and weaker for adenocarcinoma. Both COPD and RLD were associated with increased rates of total mortality.
  
  
  CONCLUSIONS
  Obstructive and restrictive impairments in lung function are associated with increased lung cancer risk.
authors.affiliation: Division of Cancer Epidemiology and Genetics, National Cancer Institute, EPS 8121, 6120 Executive Blvd, Bethesda, MD 20892-7240, USA. purduem@mail.nih.gov
authors.forename: Mark P
authors.initials: MP
authors.lastname: Purdue
authors.forename: Laura
authors.initials: L
authors.lastname: Gold
authors.forename: Bengt
authors.initials: B
authors.lastname: Järvholm
authors.forename: Michael C R
authors.initials: MC
authors.lastname: Alavanja
authors.forename: Mary H
authors.initials: MH
authors.lastname: Ward
authors.forename: Roel
authors.initials: R
authors.lastname: Vermeulen
mesh_terms: D000328:Adult; D000368:Aged; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008175:Lung Neoplasms / Q000453:epidemiology* / Q000209:etiology / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications / Q000453:epidemiology* / Q000503:physiopathology; D012129:Respiratory Function Tests; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects; D013147:Spirometry / Q000379:methods; D013548:Sweden / Q000453:epidemiology