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Table 2 Selected characteristics of participants

From: Body mass index and lung cancer risk: a pooled analysis based on nested case-control studies from four cohort studies

Characteristic

Cases (n = 4172)

N (%)

Controls (n = 8471)

N (%)

P value (X2)

Sex

0.37

 Men

3043 (72.9)

6135 (72.4)

 

 Women

1129 (27.1)

2336 (27.6)

 

Age

<.0001

  < 45

76 (1.8)

197 (2.3)

 

 45–49

211 (5.1)

980 (11.6)

 

 50–54

602 (14.4)

1720 (20.3)

 

 55–59

1010 (24.2)

2165 (25.5)

 

 60–64

1216 (29.2)

2024 (23.9)

 

 65–69

731 (17.5)

1070 (12.6)

 

  ≥ 70

326 (7.8)

324 (3.8)

 

BMI (kg/m2) a

<.0001

 Underweight

250 (5.9)

408 (4.8)

 

 Normal weight

2150 (51.5)

4276 (50.5)

 

 Overweight

112 (26.7)

2746 (32.4)

 

 Obese

373 (8.9)

934 (11.0)

 

 Missing

287 (6.9)

107 (1.3)

 

Education

<.0001

 None

529 (12.7)

699 (8.3)

 

 Primary

1515 (36.3)

2518 (29.7)

 

 Middle/Vocational

851 (20.4)

2109 (24.9)

 

 Secondary

457 (11.0)

1060 (12.5)

 

 Postsecondary/Technical

312 (7.5)

665 (7.9)

 

 University

381 (9.1)

1164 (13.7)

 

 Unknown/not specified

26 (0.6)

51 (0.6)

 

 Missing

101 (2.4)

205 (2.4)

 

Smoking status

<.0001

 Never

571 (13.7)

3144 (37.1)

 

 Former

694 (16.6)

1735 (20.5)

 

 Current

2892 (69.3)

3556 (42.0)

 

 Missing b

15 (0.36)

36 (0.4)

 

Pack-years of smoking

<.0001

 0

571 (13.7)

3144 (37.1)

 

  < 20

547 (13.1)

1562 (18.4)

 

 20–29

554 (13.3)

850 (10.0)

 

 30–39

691 (16.6)

891 (10.5)

 

 40–49

817 (19.6)

829 (9.8)

 

  ≥ 50

831 (19.9)

892 (10.5)

 

 Missing

161 (3.9)

303 (3.6)

 

Age at diagnosis of lung cancer, y

 Mean (SD)

68.0 (8.1)

–

 

 Median (range)

68.2 (38.1–91.0)

  

Time elapsed, y

 Mean (SD)

8.3 (5.4) c

13.3 (5.1) d

 

 Median (range)

7.3 (0–27)

13.0 (0–28)

 

Histological Type

 Adenocarcinoma

1182 (42.6)

  

 Squamous cell carcinoma

897 (32.6)

  

 Large cell carcinoma

221 (7.9)

  

 Small cell carcinoma

473 (17.1)

  
  1. aUnderweight (BMI < 18.5), normal weight (18.5 ≤ BMI < 25), overweight (25 ≤ BMI < 30) and obese (BMI ≥ 30)
  2. bSubjects who had missing cigarettes smoked per day and duration of smoking
  3. cPeriod between enrollment and diagnosis
  4. dPeriod between enrollment and last follow-up/observation