Table 1

Characteristics of the study cohort

Study subjects, n=399Subgroup with at least four lung function data points, n=218
Male subjects, % (n)61.2 (244)62.84 (137)
Mean age in years (SEM)50.12 (0.17)51.09 (0.70)
Current smokers, % (n)8.7 (35)7.80 (17)
Mean pack-year exposure (SEM)16.89 (0.24)15.73 (0.32)
Index cases, % (n)74.1 (296)79.6 (174)
Currently working, % (n)67.3 (268)70.8 (154)
Level of occupational risk in those still working, % (n)

High: 10.5 (28)

Low: 20.4 (55)

Zero: 69.1 (185)

High: 18.2 (28)

Low: 32.5 (50)

Zero: 49.4 (76)

Mean FEV1, %predicted (SEM)51.28 (0.50)57.41 (0.73)
Mean KCO, %predicted (SEM)73.31 (0.45)68.47 (0.57)
Chronic bronchitis, % (n)35.4 (141)38.2 (83)
Mean decline of FEV1 in ml/year (SEM)−32.66 (2.06)−34.84 (3.12)
Mean decline of KCO in (mmol/min/kPa/l)/year (SEM)−0.03 (0.004)−0.02 (0.007)
Exacerbations per year1.00 (0.33)1.00 (0.33)
  • Data are expressed as mean (SEM) for quantitative variables and are expressed as % of the cohort (n) for qualitative variables.