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Table 1 Characteristics of lung cancer cases and controls

From: Lung cancer risk and pollution in an industrial region of Northern Spain: a hospital-based case-control study

Characteristic Cases (n = 626)
n (%)
Controls (n = 626)
n (%)
P a
Sex    
   Male 541 (86.4) 541 (86.4)  
   Female 85 (13.6) 85 (13.6) 1.000
Age (yrs), mean (SD) 64.48 (10.96) 63.61 (11.21) 0.161
   median (IQR) 65.00 (17.00) 64.00 (18.00) 0.172
Hospital areab    
   Gijon (Cabueñes Hospital) 355 (56.7) 355 (56.7)  
   Aviles (San Agustin Hospital) 176 (28.1) 176 (28.1)  
   Oviedo (General Hospital) 58 (9.3) 58 (9.3)  
   Mieres (Alvarez-Buylla Hospital) 37 (5.9) 37 (5.9) 1.000
Smoking Status    
   Never 47 (7.5) 182 (29.1)  
   Ever 579 (92.5) 444 (70.9) <0.001
Former 181 (31.3) 227 (51.1)  
Current 398 (68.7) 217 (48.9) <0.001
PYc, mean (SD) 62.01 (35.34) 38.27 (31.96) <0.001
   median (IQR) 55.00 (40.75) 32.00 (35.86) <0.001
Smoking    
   Never 47 (7.6) 182 (29.6)  
   Former < 38 PY 62 (10.0) 151 (24.6)  
   Current < 38 PY 72 (11.7) 102 (16.6)  
   Former ≥ 38 PY 117 (18.9) 70 (11.4)  
   Current ≥ 38 PY 320 (51.8) 109 (17.8) <0.001
Family history of cancer    
   None 338 (56.2) 371 (59.8)  
   Other cancers 190 (31.6) 204 (32.9)  
   Lung cancer 73 (12.2) 45 (7.3) 0.015
Histologic type    
   Squamous cell carcinoma 242 (39.4)   
   Adenocarcinoma 182 (29.6)   
   Small cell carcinoma 109 (17.7)   
   Large cell carcinoma 18 (2.9)   
   Non-differentiated 42 (6.8)   
   Others 14 (2.3)   
   Clinical diagnosis 8 (1.3)   
   Missing 11   
Worker in high-risk occupation    
   Never 220 (35.4) 245 (39.3)  
   Ever 401 (64.6) 379 (60.7) 0.162
Time in high-risk occupationd, mean (SD) 26.31 (14.59) 24.24 (13.95) 0.045
   Median (IQR) 29.00 (25.00) 26.00 (23.00) 0.036
Population living in their last-residence    
   for more than 5 years 547 (88.90) 552 (89.30) 0.903
   for more than 10 years 492 (80.00) 495 (80.10) 0.977
  1. aTwo-sided χ2 test, and Mann-Whitney test where appropriate
  2. bHospital area refers to each hospital's health catchment area
  3. cPack-years for ever-smokers
  4. dTime (in years) for ever-workers