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Table 4 Associations of an interquartile-range increase in SPM (24–48 hours), ozone (72–96 hours), and SO 2 (0–24 hours) prior to emergency call with health outcomes in each subgroup of patients

From: Hourly differences in air pollution and risk of respiratory disease in the elderly: a time-stratified case-crossover study

 

Respiratory disease

Pneumonia and influenza

 

SPM (24–48 hours)

Ozone (72–96 hours)

SO2(0–24 hours)

 

OR (95% CI)a

p b

OR (95% CI)a

p b

OR (95% CI)a

p b

Age (year)

      

≥75

1.06 (1.02,1.10)

0.33

1.13 (1.03, 1.24)

0.93

1.08 (1.01, 1.16)

0.25

<75

1.01 (0.93,1.10)

 

1.14 (0.94,1.38)

 

0.99 (0.85,1.14)

 

Sex

      

Men

1.07 (1.02,1.12)

0.25

1.07 (0.95,1.19)

0.12

1.04 (0.95,1.13)

0.30

Women

1.02 (0.97,1.08)

 

1.22 (1.07,1.39)

 

1.10 (1.01,1.21)

 

Onset

      

8 am to 7 pm

1.05 (1.00,1.09)

0.69

1.12 (1.01,1.24)

0.79

1.07 (0.99,1.15)

1.00

8 pm to 7 am

1.06 (0.99,1.14)

 

1.15 (0.98,1.35)

 

1.07 (0.94,1.21)

 

Past history

      

Hypertension

      

Yes

1.08 (0.95,1.23)

0.63

1.28 (0.95,1.74)

0.37

1.25 (1.00,1.56)

0.13

No

1.05 (1.01,1.09)

 

1.11 (1.01,1.22)

 

1.05 (0.98,1.12)

 

Coronary heart disease

      

Yes

1.17 (0.94,1.46)

0.35

1.37 (0.85,2.23)

0.41

1.09 (0.77,1.53)

0.90

No

1.05 (1.01,1.09)

 

1.12 (1.02,1.22)

 

1.06 (1.00,1.14)

 

Cerebrovascular disease

      

Yes

1.03 (0.93,1.14)

0.61

1.01 (0.81,1.25)

0.28

0.94 (0.81,1.09)

0.08

No

1.06 (1.01,1.10)

 

1.15 (1.04,1.26)

 

1.09 (1.02,1.17)

 

Diabetes mellitus

      

Yes

0.99 (0.84,1.18)

0.50

0.85 (0.58,1.24)

0.14

0.98 (0.78,1.23)

0.46

No

1.05 (1.02,1.10)

 

1.14 (1.04,1.25)

 

1.07 (1.00,1.14)

 

Respiratory disease

      

Yes

1.01 (0.94,1.09)

0.24

1.15 (0.96,1.37)

0.80

0.92 (0.79,1.08)

0.04

No

1.07 (1.02,1.11)

 

1.12 (1.01,1.23)

 

1.09 (1.02,1.17)

 
  1. aAdjusted for ambient temperature (df = 6), relative humidity (df = 3), and weekly numbers of reported influenza cases aged ≥60. Interquartile ranges are 20.6 μg/m3 for SPM, 2.3 ppb for SO2, and 25.8 ppb for ozone.
  2. b p value for interaction.
  3. CI, Confidence interval; SO 2 , Sulfate dioxide; SPM, Suspended particulate matter.