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Table 5 Associations between air pollutants and preterm births by season of conception#, Sydney, 1998–2000

From: Impact of ambient air pollution on gestational age is modified by season in Sydney, Australia

 

Autumn n = 31 008

Winter n = 31 097

Spring n = 31 563

Summer n = 30 446

 

OR

95% CI

OR

95% CI

OR

95% CI

OR

95% CI

PM10 24-hour average

1.462**

1.267–1.688

1.343**

1.190–1.516

1.119

0.973–1.288

0.913**

0.889–0.937

PM2.5 24-hour average

1.080

0.912–1.281

1.426**

1.264–1.608

1.156

0.972–1.375

0.879**

0.839–0.922

O3 1-hour maximum

1.012

0.987–1.037

0.989

0.972–1.007

1.093**

1.019–1.071

1.031**

1.023–1.040

NO21 hour maximum

1.045

0.963–1.134

1.153**

1.066–1.247

1.002

0.933–1.077

0.957**

0.938–0.976

CO 8 hour maximum

0.114**

0.086–0.152

0.134**

0.062–0.281

0.584

0.283–1.462

0.633**

0.535–0.750

SO2 1-hour maximum

6.489**

4.365–9.648

1.323**

1.027–1.704

1.287

0.955–1.734

0.826**

0.759–0.898

  1. #Analysis for the first trimester of pregnancy; OR estimates adjusted for: maternal age, maternal smoking during pregnancy, indigenous status, SES, gestational age at first antenatal visit and parity. OR is for a one unit increase in air pollutant concentration; *p < 0.05; **p < 0.01