Skip to main content

Advertisement

Table 5 Relative risks of pediatric asthma HAs (5–14 years) per 10-ppb increase in daily 8-h maximum O3 concentrations, stratified by time period, with adjustments for pollen and respiratory infections, in Dallas, Houston, and Austin, Texas from 2003 to 2011

From: Ambient ozone and asthma hospital admissions in Texas: a time-series analysis

O3 concentrations Model 1a Model 2b Model 3c
Full year Full year August–September October–July
Same day 1.023
(1.004–1.043)
1.023
(1.004–1.043)
1.036
(1.007–1.066)
1.017
(0.995–1.039)
Pinteraction = 0.24
Lag 1 day 1.022
(1.004–1.040)
1.021
(1.003–1.040)
1.025
(0.997–1.054)
1.020
(0.999–1.041)
Pinteraction = 0.75
Lag 2 day 1.016
(0.998–1.034)
1.016
(0.998–1.034)
1.040
(1.012–1.069)
1.006
(0.986–1.026)
Pinteraction = 0.03
Lag 0–3 days 1.031
(1.005–1.058)
1.031
(1.005–1.057)
1.053
(1.015–1.093)
1.020
(0.991–1.050)
Pinteraction = 0.12
  1. HA hospital admission, ppb parts per billion, SD standard deviation, O 3 ozone
  2. aModel 1 adjusted for cubic splines of calendar time (8 d.f. per year), cubic splines of same-day temperature (3 d.f.), cubic splines of the average of lag 1 through 3 day temperature (3 d.f.), cubic splines of same-day dew point (3 d.f.), cubic splines of the average of lag 1 through 3 day dew point (3 d.f.), day of the week, public holidays, total pollen counts (lag 0–2 days, categorical), and total respiratory infection HAs (lag 0–2 days, cubic splines with 3 d.f.)
  3. bModel 2 was Model 1 with additional adjustment for the start of school year (indicator variable for August/September)
  4. cModel 3 was Model 1 with additional adjustment for the start of school year (indicator variable for August/September) and the interaction between the start of school year and ambient O3 concentrations