Table 1 Characteristics of selected lung cancer cases and frequency matched controls: Yunnan, China 1992-1998

Age

0.914

 40–49

3

(1.6)

4

(1.8)

 50–59

58

(31.7)

71

(32.7)

 60–69

104

(56.8)

125

(57.6)

 70–79

18

(9.8)

17

(7.8)

Education level^a

0.043

 None

82

(44.8)

87

(40.1)

 K–5

89

(48.6)

98

(45.2)

 6–8

9

(4.9)

15

(6.9)

 9–12

2

(1.1)

5

(2.3)

 College

1

(0.5)

12

(5.5)

Body Mass Index (BMI) (kg/m²)

0.230

 Underweight (<18.5)

18

(9.8)

36

(16.6)

 Normal (18.5–24.99)

138

(75.4)

150

(69.1)

 Overweight (25–29.99)

24

(13.1)

29

(13.4)

 Obese (≥30)

3

(1.6)

2

(0.9)

Ever smoked tobacco^b

177

(96.7)

197

(90.8)

0.016

Pack-years, median (IQR^c)

36

(24–54)

32

(19–49)

0.132

Arsenic^d, median (IQR^c)

10745

(6695–15347)

9420

(4888–16802)

0.057

Radon^e, median (IQR^c)

498

(277–783)

417

(171–681)

0.132

Family history of lung cancer^f

3

(1.6)

6

(2.8)

0.449

Any prior lung disease^g

88

(48.1)

98

(45.2)

0.559

 Asthma or hay fever

25

(13.7)

24

(11.1)

0.429

 Tuberculosis (self-report)

8

(4.4)

14

(6.5)

0.363

 Chronic bronchitis

72

(39.3)

78

(35.9)

0.484

 Silicosis

20

(10.9)

18

(8.3)

0.371

Lung cancer histology

NA

 Squamous cell carcinoma

72

(39.3)

0

(−)

 Adenocarcinoma

31

(16.9)

0

(−)

 Small cell carcinoma

25

(13.7)

0

(−)

 Mixed

19

(10.4)

0

(−)

 Other

2

(1.1)

0

(−)

 Not obtained

34

(18.6)

0

(−)

Lung cancer site

NA

 Main bronchus

15

(8.2)

0

(−)

 Upper lobe bronchus or lung

76

(41.5)

0

(−)

 Middle lobe lung

19

(10.4)

0

(−)

 Lower lobe bronchus or lung

60

(32.8)

0

(−)

 Other parts of bronchus or lung

3

(1.6)

0

(−)

 Bronchus and lung NOS

10

(5.5)

0

(−)