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Table 2 Associations between smoking variables and lung cancer

From: Risk of lung cancer among women in relation to lifetime history of tobacco smoking: a population-based case-control study in France (the WELCA study)

 

Cases N = 716 (%)

Controls N = 757 (%)

OR (95%CI) a

p trend

SMOKING STATUS b

 Never smokers

142 (19.8)

341 (45.1)

Ref

 

 Former smokers

201 (28.1)

246 (32.5)

2.15 (1.62; 2.84)

 

 Current smokers

373 (52.1)

170 (22.5)

5.22 (3.96; 6.89)

 

INTENSITY, cigarettes/day

mean (SD)*

18.5 (8.9)

12.5 (9.2)

  

 Never smokers

142 (19.8)

341 (45.1)

Ref

 

  < 10

80 (11.2)

175 (23.2)

1.11 (0.79; 1.56)

 

 10–19

286 (39.9)

150 (19.8)

4.69 (3.52; 6.26)

 

 20–29

148 (20.7)

72 (9.5)

5.40 (3.78; 7.70)

 

  ≥ 30

60 (8.4)

18 (2.4)

9.63 (5.37; 17.24)

<  0.001

Per 10 cigarettes/day

 

2.27 (2.02; 2.56)

 

DURATION OF TOBACCO SMOKING, years

mean (SD)*

36.5 (11.6)

26.4 (14.8)

  

 Never smokers

142 (19.8)

341 (45.1)

Ref

 

  < 20

62 (8.7)

150 (19.8)

1.07 (0.74; 1.55)

 

 20–29

74 (10.3)

76 (10.1)

2.19 (1.49; 3.23)

 

 30–39

184 (25.7)

94 (12.4)

4.80 (3.46; 6.65)

 

  ≥ 40

254 (35.5)

95 (12.6)

7.43 (5.36; 10.30)

<  0.001

Per 10 years

 

1.59 (1.49; 1.70)

 

PACK-YEARS

mean (SD)*

35.4 (21.0)

18.5 (17.5)

  

 Never smokers

142 (19.8)

341 (45.1)

Ref

 

  < 10

57 (8)

173 (22.9)

0.81 (0.56; 1.17)

 

 10–19

83 (11.6)

86 (11.4)

2.40 (1.66; 3.48)

 

 20–29

106 (14.8)

58 (7.7)

4.37 (2.97; 6.44)

 

  ≥ 30

328 (45.8)

98 (13.0)

9.16 (6.68; 12.54)

<  0.001

Per 10 pack-years

  

1.65 (1.54; 1.76)

 

TIME SINCE TOBACCO SMOKING CESSATION, years

mean (SD)*

11.7 (10.7)

24.0 (14.6)

  

 Never smokers

142 (19.8)

341 (45.1)

Ref

 

 Current smokers

373 (52.1)

170 (22.5)

5.30 (4.02; 7.00)

 

 2–9

84 (11.7)

45 (5.9)

4.78 (3.14; 7.27)

 

 10–19

65 (9.1)

58 (7.7)

2.78 (1.84; 4.20)

 

  ≥ 20

52 (7.3)

143 (18.9)

0.97 (0.66; 1.42)

<  0.001

Per 1 year (among ever smokers)

  

0.94 (0.93; 0.96)

 

CSI c

mean (SD)*

1.6 (0.6)

1.0 (0.7)

  

 Never smokers

142 (19.8)

341 (45.1)

Ref

 

  <  0.69

67 (9.4)

181 (23.9)

0.98 (0.69; 1.39)

 

 0.69–1.45

130 (18.2)

116 (15.3)

2.71 (1.95; 3.75)

 

 1.46–1.95

173 (24.2)

74 (9.8)

5.69 (4.02; 8.04)

 

  ≥ 1.96

204 (28.5)

44 (5.8)

12.64 (8.50; 18.80)

<  0.001

Per 1 CSI unit

  

3.13 (2.71; 3.61)

 
  1. Abbreviations: CI confidence interval; CSI comprehensive smoking index; OR odds ratio; SD standard deviation
  2. * Mean and SD were calculated among ever smokers using the Student test
  3. a ORs were adjusted for age (continuous), area of residence, education, and BMI 2 years before the interview (continuous)
  4. b Ever smoker correspond to a person who have smoked at least 100 cigarettes throughout life; former smoker correspond to a person who have stopped smoking for at least 2 years before the interview (or before the diagnosis for cases)
  5. c Quartiles among controls and cases