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Table 3 Odds ratios (ORs) and confidence intervals (CIs) for ischemic stroke risk in relation to residential modelled outdoor annual mean concentration of NOX.

From: Long-term exposure to air pollution and hospital admissions for ischemic stroke. A register-based case-control study using modelled NOxas exposure proxy

 

First-phase analysis

Second-phase analysis

Two-phase analysis

   

Partly adjusteda

   

Partly adjustedb

 

Fully adjustedc

   

NOX

μg/m3

Cases

N(%)

Controls

N(%)

ORd

CI

Cases

N(%)

Controls

N(%)

ORe

CI

ORf

CI

ORg

CIh

0–<10

1667 (34)

197371 (35)

1

 

1492 (34)

1784 (38)

1

 

1

 

1

 

10–<20

1944 (40)

221981 (40)

1.03

0.97–1.10

1699 (39)

1923 (41)

1.07

0.91–1.25

1.00

0.85–1.2

0.97

0.90–1.05

20–<30

1065 (22)

110001 (20)

1.05

0.97–1.14

981 (22)

867 (18)

1.10

0.87–1.39

1.00

0.79–1.3

0.95

0.86–1.06

30–<60i

228 (5)

27559 (5)

0.91

0.79–1.05

203 (5)

142 (3)

1.28

0.90–1.82

1.20

0.85–1.76

0.87

0.73–1.03

  1. Partly adjusted first- and second-phase estimates, fully adjusted second-phase estimates and two-phase estimates: The two-phase estimates were calculated according to formula 1.
  2. a Adjusted for birth year category, sex, birth country and marital status.
  3. b Adjusted for a and for geographical area.
  4. c Adjusted for a, b and for smoking, diabetes and medication for hypertension.
  5. d The partly adjusted first-phase OR for an increase of 10 μg/m3 in NOx was OR1;Partl_adj= 0.99 (0.95–1.02), p for trend = 0.44.
  6. e The partly adjusted second-phase OR for an increase of 10 μg/m3 in NOx was OR2;Partly_adj= 1.09 (0.95–1.26), p for trend p = 0.21.
  7. f The fully adjusted second-phase OR for an increase of 10 μg/m3 in NOx was OR2;Fully_adjj= 1.07 (0.93–1.24), p = 0.33
  8. g The two-phase OR for an increase of 10 μg/m3 in NOx was OR1+2 = 0.97.
  9. h The widths of the two-phase CIs are likely slightly overestimated, due to dependence between the three combined estimates that we did not take into account.
  10. iMedian level of NOx in the category 30–<60 μg/m3 is 33.0 μg/m3 (10th–90th percentile: 30.4–40.5)