Table 6 Conditional logistic regression models for lifetime exposure to cooking fuels.

All subjects

Wood or dry leaves ever used

47

109

1 (ref)

1 (ref)

0.15

Used ≤25000 hours

55

96

1.67 (0.89, 3.15)

1.93 (0.95, 3.91)

Used >25000 hours

51

101

1.71 (0.71. 4.11)

2.40 (0.85, 6.79

Trend

1.52 (0.93, 2.49)

0.10

Rice straw

Never used

124

266

1 (ref)

1 (ref)

0.07

Used ≤24000 hours

12

16

1.60 (0.73, 3.51)

1.87 (0.74, 4.68)

Used >24000 hours

17

24

1.61 (0.79, 3.31)

2.18 (0.98, 4.86)

Trend

1.53 (1.06, 2.24)

0.02

Cow dung

Never used

127

235

1 (ref)

1 (ref)

0.02

Used≤1500 hours

12

36

0.57 (0.28, 1.17)

0.43 (0.20, 0.92)

Used >31500 hours

14

35

0.66 (0.33, 1.34)

0.44 (0.20, 0.99)

Ever used/never used

0.42 (0.23, 0.79)

0.005

Females

Wood or dry leaves

Used ≤25000 hours

30

60

1 (ref)

1 (ref)

0.56

Used >25000 hours

50

100

1.00 (0.53. 1.89)

1.27 (0.56, 2.87)

Rice straw

Never used

54

123

1 (ref)

1 (ref)

0.09

Used ≤24000 hours

9

13

1.46 (0.61, 3.51)

1.75 (1.62, 5.00)

Used >24000 hours

17

24

1.61 (0.78, 3.29)

2.21 (0.98, 4.94)

Trend

1.52 (1.04, 2.22)

0.03

Cow dung

Never used

55

90

1 (ref)

1 (ref)

0.03

Used≤31500 hours

11

35

0.53 (0.25, 1.11)

0.42 (0.19, 0.93)

Used >31500 hours

14

35

0.65 (0.32, 1.32)

0.43 (0.22, 0.81)

Ever used/never used

0.43 (0.22, 0.81)

0.007