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Table 1 Distribution of demographic and risk factor characteristics for all participants in analytic sample by smoking status

From: A case-only study of gene-environment interaction between genetic susceptibility variants in NOD2 and cigarette smoking in Crohn's disease aetiology

 

Ever Smokers

Never Smokers

 

Smokers at Diagnosis

Non-Smokers at Diagnosis

 

Total Sample

Characteristic

n

%

n

%

p-value

n

%

n

%

p-value

n

%

Total Participants n = 1636

945

57.8%

691

42.2%

 

522

40.7%

761

59.3%

 

1636

100.0%

Sex

    

0.09

    

0.02

  

   Men

281

29.7%

233

33.7%

 

144

27.6%

258

33.9%

 

514

31.4%

   Women

664

70.3%

458

66.3%

 

378

72.4%

503

66.1%

 

1122

68.6%

Age at Inclusion--Mean

(Standard Deviation)

40.8

± 10.9

36.3

± 12.9

2 × 10 -13

41.1

± 10.6

38.8

± 13.5

6 × 10 -4

38.9

± 12.0

Age at Diagnosis--Mean

(Standard Deviation)

27.4

± 10.1

24.1

± 10.1

7 × 10 -11

27.3

± 9.5

26.0

± 11.4

0.03

26

± 10.3

Family History

    

0.17

    

0.43

  

   Yes

229

24.2%

196

28.4%

 

75

14.4%

128

16.8%

 

425

26.0%

   No

463

49.0%

320

46.3%

 

295

56.5%

408

53.6%

 

783

47.9%

   Unknown

253

26.8%

175

25.3%

 

152

29.1%

225

29.6%

 

428

26.2%

Combined Allele Analysis

    

1 × 10 -4

    

0.001

  

   Wild Type

549

58.1%

336

48.6%

 

311

59.6%

384

50.5%

 

885

54.1%

   Carrier of ≥ 1 risk allele

396

41.9%

355

51.4%

 

211

40.4%

377

49.5%

 

751

45.9%

R702W Polymorphism

    

0.12

    

0.34

  

   Wild Type (C/C)

776

82.1%

540

78.1%

 

429

82.2%

608

79.9%

 

1316

80.4%

   Heterozygote for risk allele (C/T)

153

16.2%

134

19.4%

 

85

16.3%

133

17.5%

 

287

17.5%

   Homozygote for risk allele (T/T)

16

1.7%

17

2.5%

 

8

1.5%

20

2.6%

 

33

2.0%

G908R Polymorphism

    

0.93

    

0.12

  

   Wild Type (G/G)

858

90.8%

626

90.6%

 

475

91.0%

689

90.5%

 

1484

90.7%

   Heterozygote for risk allele (G/C)

84

8.9%

62

9.0%

 

47

9.0%

66

8.7%

 

146

8.9%

   Homozygote for risk allele (C/C)

3

0.3%

3

0.4%

 

0

0.0%

6

0.8%

 

6

0.4%

1007fs Polymorphism

    

1 × 10 -4

    

7 × 10 -6

  

   Wild Type (-/-)

735

77.8%

477

69.0%

 

420

80.5%

524

68.9%

 

1212

74.1%

   Heterozygote for risk allele (-/C)

174

18.4%

166

24.0%

 

88

16.9%

187

24.6%

 

340

20.8%

   Homozygote for risk allele (C/C)

36

3.8%

48

6.9%

 

14

2.7%

50

6.6%

 

84

5.1%