Table 7 Geographical stratification. Chronic bronchitis symptoms in the city of Malmö and the area outside.

n

Chronic b. symptoms

OR ^a

n

Chronic b. symptoms

OR ^a

Heavy traffic

No

1767

150(8.5%)

1.00

4178

246(5.9%)

1.00

Yes

1877

140(7.5%)

0.91(0.71–1.16)

1343

92(6.9%)

1.20(0.94–1.54)

Heaviest road within <100 m

no heavy road

586

43(7.3%)

1.00

3124

179(5.7%)

1.00

<2 cars/min

1021

89(8.7%)

1.21(0.83–1.77)

1193

68(5.7%)

1.00(0.75–1.34)

2–5 cars/min

837

66(7.9%)

1.10(0.73–1.64)

961

69(7.2%)

1.30(0.98–1.74)

6–10 cars/min

663

47(7.1%)

0.94(0.61–1.45)

212

19(9.0%)

1.63(0.99–2.69)

>10 cars/min

537

45(8.4%)

1.22(0.78–1.89)

31

3

-

NO_x (μg/m³)

0–8

13

0

-

1824

109(6.0%)

1.00

8–11

46

4

-

1792

113(6.3%)

1.04(0.79–1.37)

11–14

562

35(6.2%)

1.00

1268

84(6.6%)

1.17(0.87–1.57)

14–19

1325

96(7.2%)

1.13(0.76–1.70)

510

26(5.1%)

0.88(0.57–1.37)

>19

1698

155(9.1%)

1.57(1.06–2.30)

127

6(4.7%)

0.86(0.37–2.01)

p-trend

0.017

p-trend

0.541