Table 1

Characteristics of the study population by case–control status and sex

Study participants’ characteristicsMale n (%)P value*Female n (%)P value*
Cases
501 (17.3)
Controls
2398 (82.7)
Cases
157 (12.7)
Controls
1079 (87.3)
Age categories, yearsN (%)N (%)<0.001N (%)N0.070
 <4012 (2.4)204 (8.5)8 (5.1)114 (10.6)
 40–4416 (3.2)95 (3.9)6 (3.8)73 (6.8)
 45–4938 (7.6)222 (9.2)14 (8.9)108 (10.0)
 50–5458 (11.6)325 (13.5)22 (14.0)149 (13.8)
 55–59106 (21.1)423 (17.6)24 (15.3)173 (16.0)
 60–64103 (20.6)430 (17.9)22 (14.0)184 (17.0)
 65–6977 (15.4)331 (13.8)32 (20.4)147 (13.6)
 70–7446 (9.2)206 (8.6)15 (9.5)83 (7.7)
 75–7927 (5.4)99 (4.1)7 (4.5)26 (2.4)
 80–8417 (3.4)47 (1.2)3 (1.2)15 (1.4)
 85+1 (0.2)16 (0.7)4 (2.5)7 (0.6)
Cigarette smoking status<0.0010.216
 Never smokers103 (20.6)1442 (60.1)146 (93.0)1036 (96.0)
 Current smokers212 (42.3)440 (18.4)5 (3.2)18 (1.7)
 Former smokers186 (37.1)515 (21.5)6 (3.8)25 (2.3)
Intensity of smoking (pack/year) in ever smokers<0.0010.026
 <1055 (11)359 (15.0)4 (2.5)27 (2.5)
 10–2048 (9.6)167 (7.0)4 (2.5)5 (0.5)
 >20295 (58.9)430 (17.9)3 (1.9)11 (1.0)
Opium consumption status (times/day)<0.001<0.001
 Never213 (42.5)1970 (82.1)133 (84.7)1056 (97.8)
 <1/day103 (20.6)295 (12.3)5 (3.2)19 (1.8)
 1–2/day120 (23.9)99 (4.1)11 (7.0)2 (0.2)
 >2/day65 (13.0)34 (1.4)8 (5.1)2 (0.2)
Waterpipe smoking0.024<0.001
 Never455 (90.8)2245 (93.6)127 (80.9)993 (92.0)
 Ever46 (9.2)153 (6.4)30 (19.1)86 (8.0)
Environmental tobacco smoke0.047<0.001
 Never317 (63.3)1752 (73.1)88 (56.1)693 (64.2)
 Ever184 (36.7)646 (26.9)69 (43.9)386 (35.8)
Respiratory disease history<0.001<0.001
 Never451 (90.0)2259 (94.2)131 (83.4)1026 (95.1)
 Ever50 (10.0)139 (5.8)26 (16.6)53 (4.9)
Histopathology classification
 Epithelial tumours
  Adenocarcinoma168 (33.5)81 (51.6)
  Squamous cell carcinoma148 (29.5)28 (17.8)
  Neuroendocrine tumours99 (19.7)15 (9.5)
  Other epithelial neoplasm57 (11.4)21 (13.4)
 Non-epithelial tumours15 (3.0)7 (4.5)
 Missing14 (2.8)5 (3.2)
The longest occupation held (major groups of ISCO-68)<0.0010.6
 0/1: Professional, technical and related workers31 (6.2)266 (11.1)7 (4.5)53 (4.9)
 2: Administrative and managerial workers4 (0.8)61 (2.5)2 (1.3)10 (0.9)
 3: Clerical and related workers27 (5.4)212 (8.8)2 (1.3)16 (1.4)
 4: Sales workers38 (7.6)181 (7.5)0 (0.0)11 (1.0)
 5: Service workers22 (4.4)125 (5.2)0 (0.0)32 (3.0)
 6: Agricultural, animal husbandry and forest140 (27.9)541 (22.6)8 (5.1)58 (5.4)
 7: Craft and related trades workers29 (5.6)147 (6.1)6 (3.8)39 (3.6)
 8: Plant and machine operators48 (9.6)172 (7.2)0 (0.0)1 (0.1)
 9: Elementary occupations152 (30.3)554 (23.1)1 (0.6)4 (0.4)
 X: Military force9 (1.8)130 (5.4)
 X1: Housewives131 (83.4)849 (78.7)
 Missing, students, jobless1 (0.2)9 (04)0 (0.0)6 (0.5)
  • *P value calculated using the χ2 test.

  • –, no data; ISCO-68, International Standard Classification of Occupations.