Table 1

Characteristic of the population

Study characteristicsn (%)*95% CI
Age, years (mean, SD) (n=1334)44.8 (0.8)44.7 to 44.9
Sex, % (n=1335)
 Men684 (51.6)48.5 to 54.9
 Women651 (48.3)45.0 to 51.5
Smoking history (n=1330)
 Never, n (%)566 (45.3)42.1 to 48.6
 Past, n (%)
 Pack-years, median (IQR) (n=1292)
394 (29.6)
7.5 (2–17)
26.7 to 32.6
 Current, n (%)
 Pack-years, median (IQR) (n=1292)
370 (25.1)
21 (10–30)
22.4 to 27.9
Currently employed, n (%) (n=1332)1136 (87.4)85.2 to 89.3
Fixed airflow obstruction (AO)
 Fixed AO-GOLD (n=1335)113 (6.0)4.8 to 7.6
  Stage I: FEV1/FVC <0.7 and FEV≥80%62 (3.7)2.7 to 5.1
  Stage II: FEV1/FVC <0.7 and FEV<80%51 (2.3)1.7 to 3.2
 Fixed AO-LLN (n=1335)112 (6.0)4.8 to 7.5
 Chronic bronchitis (n=1322)246 (8.7)7.6 to 9.9
Respiratory symptoms
 Chronic cough (n=1316)185 (8.8)7.4 to 10.3
 Chronic phlegm (n=1317)171 (6.8)5.8 to 8.1
 Dyspnoea (n=1334)227 (12.1)10.4 to 14.1
  • *The estimated prevalences were calculated using inverse-probability-of-inclusion weights to adjust for the enriched sample of the fifth decade follow-up survey.

  • AO, airflow obstruction; GOLD, Global Obstructive Lung Disease; LLN, lower limit of normal.