Table 3.
Interactions between Air Pollution and Airway-to-Lung Ratio on FEV1 and Chronic Obstructive Pulmonary Disease Prevalence
| Difference in FEV1, β (95% CI), ml |
||
|---|---|---|
| Airway-to-Lung Ratio (per IQR Decrease) | P Value Interaction | |
| PM2.5 (per IQR increase = 2.4 μg/m3) | −38.3 (−82.2 to 5.6) | 0.087 |
| NO2 (per IQR increase = 9.2 ppb) | 19.4 (−37.7 to 76.4) | 0.505 |
| Difference in COPD OR (95% CI) |
||
|---|---|---|
| Airway-to-Lung Ratio (per IQR Decrease) | P Value Interaction* | |
| PM2.5 (per IQR increase = 2.4 μg/m3) | 1.26 (0.98 to 1.62) | 0.065 |
| NO2 (per IQR increase = 9.2 ppb) | 1.03 (0.77 to 1.40) | 0.826 |
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.
Airway-to-lung ratio modeled using continuous linear terms. 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 (continuous), 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 continuous airway-to-lung ratio.