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Table 3 Meta-analyzed relative risk estimates of allergy medication fills and allergic rhinitis physician visits (first visit in calendar year) on days designated as – (i) ‘high’ pollen level based on same day imputed values, (ii) ‘high’ pollen based on 7-day average of imputed values; (iii) ‘high’ pollen based on same day non-imputed values of pollen (with missing pollen observations), (iv) days with pollen concentrations >=75th percentile of the pollen distribution during the study period. ’High’ pollen level is defined by pollen concentrations (grains/m3) – 250 < Tree < 1500; 50 < grass < 100, 100 < weed < 250. Relative risk estimates derived from models with weekly ILI index, air pollution measures (daily PM2.5 and Ozone) and meteorological factors (daily maximum temperature, total precipitation, and average wind speed) as covariates

From: Short term physician visits and medication prescriptions for allergic disease associated with seasonal tree, grass, and weed pollen exposure across the United States

Allergy medication fills
  Tree pollen Grass pollen Weed pollen
Pollen measure RR 95% CI   RR 95% CI   RR 95% CI  
Same day (imputed) 1.11 1.09 1.14 1.03 0.99 1.07 1.08 1.06 1.10
7 day average (imputed) 1.16 1.13 1.18 1.03 0.98 1.08 1.11 1.08 1.15
Same day (non-imputed) 1.10 1.08 1.13 1.05 1.02 1.08 1.09 1.07 1.11
Days in top quartile of pollen 1.11 1.09 1.14 1.03 0.99 1.07 1.06 1.04 1.08
Physician visit for allergic rhinitis
  Tree pollen Grass pollen Weed pollen
Pollen measure RR 95% CI RR 95% CI RR 95% CI
Same day (imputed) 1.20 1.10 1.31 1.29 1.15 1.42 1.31 1.15 1.47
7 day average (imputed) 1.31 1.13 1.49 1.35 1.19 1.51 1.48 1.28 1.67
Same day (non-imputed) 1.20 1.10 1.30 1.33 1.19 1.47 1.28 1.12 1.43
Days in top quartile of pollen 1.14 1.06 1.23 1.28 1.16 1.41 1.24 1.10 1.38