Table 1

Demographics

ReferentsTFWP values
Participantsn=69 (%)n=69 (%)
Age
 Overall mean±SD50.0±13.241.0±12.26.0x10−5*
Gender (%)
 Male69 (100)69 (100)
Ethnic group (%)
 Caucasian69 (100)69 (100)
Smoking history (%)‡0.003†
 Never-smoker28 (41)17 (25)
 Former-smoker (less than a year)1 (2)6 (9)
 Former-smoker (more than a year)19 (28)11 (16)
 Daily-smoker8 (12)24 (35)
 Party-smoker11 (16)11 (16)
BMI (SD)§27.5 (3.7)27.2 (3.9)
Respirator mask (%)¶0.001†
 Yes, often1 (1)5 (7)
 Yes, rarely26 (38)43 (62)
 No42 (61)20 (29)
Respiratory diseases (%)**††
Chronic bronchitis3 (4)1 (1)
Chronic obstructive lung disease1 (1)0 (0)
  • *Student’s t-test.

  • †Pearson χ2.

  • ‡Two cases (4%) from the referent group were missing data on smoking status.

  • §Eight cases (12%) from the referent group and two cases (3%) from the TFW group were missing data on BMI.

  • ¶One case (1%) from the TFW group was missing data on use of respirators.

  • **One case (1%) from the referent group and four cases (6%) from the TFW group were missing data on chronic bronchitis.

  • ††Five cases (7%) from the referent group and two cases from the TFW group were missing data on chronic obstructive lung disease.

  • BMI, body mass index; TFW, tunnel finishing worker.