Table 4.
Interactions between Air Pollution and Airway-to-Lung Ratio on FEV1 and Chronic Obstructive Pulmonary Disease Prevalence
| Difference in FEV1 (ml), β (95% CI) |
|||||
|---|---|---|---|---|---|
| All Participants | Highest Quartile of Airway-to-Lung Ratio | Lowest Quartile of Airway-to-Lung Ratio | Difference between Highest and Lowest Quartile | P Value Interaction* | |
| PM2.5 (per IQR increase = 2.4 μg/m3) |
−107.0 (−175.9 to −38.0) | −70.8 (−160.5 to 18.9) | −180.5 (−273.9 to −87.2) | −109.8 (−209.0 to −10.5) | 0.030 |
| NO2 (per IQR increase = 9.2 ppb) |
−149.5 (−234.7 to −64.2) | −185.0 (−306.5 to −63.4) | −145.3 (−254.8 to −35.7) | 39.7 (−89.9 to 169.4) | 0.548 |
| Difference in COPD OR (95% CI) |
|||||
|---|---|---|---|---|---|
| All Participants | Highest Quartile of Airway-to-Lung Ratio | Lowest Quartile of Airway-To-Lung Ratio | Relative Difference between Highest and Lowest Quartile | P Value Interaction* | |
| PM2.5 (per IQR increase = 2.4 μg/m3) |
1.22 (0.89 to 1.69) | 0.96 (0.62 to 1.48) | 1.79 (1.11 to 2.88) | 1.87 (1.12 to 3.13) | 0.015 |
| NO2 (per IQR increase = 9.2 ppb) |
1.18 (0.8 to 1.75) | 1.04 (0.58 to 1.89) | 1.55 (0.90 to 2.65) | 1.48 (0.78 to 2.81) | 0.220 |
Definition of abbreviations: CI = confidence interval; COPD = chronic obstructive pulmonary disease; IQR = interquartile range; NO2 = nitrogen dioxide; OR = odds ratio; PM2.5 = fine particulate matter.
Highest versus lowest airway-to-lung ratio quartiles. All models are adjusted for age, sex, body mass index, educational level (high school or lower vs. postsecondary education), tobacco status (never smoker, former smoker, or current smoker), pack-years smoking, environmental tobacco smoke at home, biomass fuel exposure, respiratory medication intake, dysanapsis (quartiles), and Canadian Cohort Obstructive Lung Disease study site. Statistically significant results are shown in bold.
To test for interactions, a product term was included between air pollution and airway-to-lung ratio quartiles.