Table 3 Distribution of parameters of cooking history and cooking fuel use among cases and controls.

Cooking history

   Ever cooked

0.18

0.59

Yes

108 (70.6)

100 (65.4)

105 (68.6)

No

45 (29.4)

53 (34.6)

48 (31.4)

   Frequency

0.56

1.00

Regular

87 (80.6)

84 (84.0)

83 (79.0)

Occasional

21 (19.4)

16 (16.0)

22 (21.0)

   Place

0.22

0.16

Living house

33 (30.6)

21 (21.0)

20 (19.0)

Separate house

75 (69.4)

79 (79.0)

85 (81.0)

   Duration

0.10

0.003

≤26 yr

53 (49.1)

48 (48.0)

65 (61.9)

>26 yr

55 (50.9)

52 (52.0)

40 (38.1)

Wood/dry leaves

   Ever used

0.05

0.45

Used

106 (69.3)

95 (62.1)

102 (66.7)

Never used

47 (30.7)

58 (37.9)

51 (33.3)

   Age at 1^st exposure

0.15

0.42

Never exposed

47 (30.7)

58 (37.9)

51 (33.3)

Exposed at ≤15 years

56 (36.6)

45 (29.4)

60 (39.2)

Exposed at <15 years

50 (32.7)

50 (32.7)

42 (27.5)

   Frequency of use

0.12

0.63

Never used

47 (30.7)

58 (37.9)

51 (33.3)

Used≤14 times/week

98 (64.1)

85 (55.6)

90 (58.8)

Used>14 times/week

8 (5.2)

10 (6.5)

12 (7.8)

   Intensity of use

0.09

0.44

Never used

47 (30.7)

58 (37.9)

51 (33.3)

Used≤20 hr/week

64 (41.8)

50 (32.7)

56 (36.6)

Used>20 hr/week

42 (27.5)

45(29.4)

46 (30.1)

   Duration of use

0.15

0.02

Never used

47 (30.7)

58 (37.9)

51 (33.3)

Used ≤26yr

52 (34)

43 (28.1)

61 (39.9)

Used >26yr

54 (35.3)

52 (34.0)

41 (26.8)

   Life time exposure

0.15

0.74

Never used

47 (30.7)

58 (37.9)

51 (33.3)

Used≤25000 hr

55 (35.9)

44 (28.8)

52 (34.0)

Used>25000 hr

51 (33.3)

51 (33.3)

50 (32.7)

Rice straw

   Ever used

0.05

0.27

Used

29 (19.0)

18 (11.8)

22 (14.4)

Never used

124 (81.0)

135 (88.2)

131 (85.6)

   Age at 1^st exposure

0.03

0.22

Never exposed

124 (81.0)

135 (88.2)

131 (85.6)

Exposed at ≤15 years

11 (7.2)

11 (7.2)

13 (6.5)

Exposed at <15 years

18 (11.8)

7 (4.6)

9 (7.8)

   Frequency of use

0.14

0.19

Never used

124 (81.0)

135 (88.2)

131 (85.6)

Used≤14 times/week

25 (16.3)

18 (11.8)

21 (13.7)

Used>14 times/week

4 (2.6)

0 (0.0)

1 (0.7)

   Intensity of use

0.15

0.28

Never used

124 (81)

135 (88.2)

131 (85.6)

Used≤20 hr/week

16 (10.5)

10 (6.5)

12 (7.8)

Used>20 hr/week

13 (8.5)

8 (5.2)

10 (6.5)

   Duration of use

0.07

0.42

Never used

124 (81)

135 (88.2)

131 (85.6)

Used ≤26yr

12 (7.8)

10 (6.5)

11 (7.2)

Used >26yr

17 (11.1)

8 (5.2)

11 (7.2)

   Life time exposure

0.15

0.55

Never used

124 (81)

135 (88.2)

131 (85.6)

Used≤24000 hr

12 (7.8)

7 (4.6)

9 (5.9)

Used>24000 hr

17 (11.1)

11 (7.2)

13 (8.5)

Cow dung

   Ever used

0.20

0.08

Used

26 (17.0)

34 (22.2)

37 (24.2)

Never used

127 (83.0)

119 (77.8)

116 (75.8)

   Age at 1^st exposure

0.45

0.13

Never exposed

127 (83.0)

119 (77.8)

116 (75.8)

Exposed at ≤14 years

14 (9.2)

18 (11.8)

25 (16.3)

Exposed at <14 years

12 (7.8)

16 (10.5)

12 (7.8)

   Frequency of use

0.28

0.16

Never used

127 (83.0)

119 (77.8)

116 (75.8)

Used≤14 times/week

24 (15.7)

34 (22.2)

34 (22.2)

Used>14 times/week

2 (1.3)

0 (0.0)

3 (2.0)

   Intensity of use

0.42

0.22

Never used

127 (83.0)

119 (77.8)

116 (75.8)

Used≤20 hr/week

11 (7.2)

16 (10.5)

15 (9.8)

Used>20 hr/week

15 (9.8)

18 (11.8)

22 (14.4)

   Duration of use

0.44

0.12

Never used

127 (83.0)

119 (77.8)

116 (75.8)

Used ≤26yr

10 (6.5)

14 (9.2)

19 (12.4)

Used >26yr

16 (10.5)

20 (13.1)

18 (11.8)

   Life time exposure

0.45

0.19

Never used

127 (83.0)

119 (77.8)

116 (75.8)

Used≤31500 hr

12 (7.8)

16 10.5)

20 (13.1)

Used>31500 hr

14 (9.2)

18 (11.8)

17 (11.1)