Roles of the physical environment in health-related quality of life in patients with chronic obstructive pulmonary disease

Abstract

Rationale: Many clinical and psychological factors are known to influence the health-related quality of life (HRQL) in chronic obstructive pulmonary disease (COPD). However, research on whether environmental factors, such as air pollution, noise, temperature, and blue/green spaces also influence HRQL in COPD has not been systematically investigated.

Objective: To assess the relationship between air pollution, road traffic noise, temperature, and distance to blue/green spaces and respiratory-specific HRQL in COPD.

Methods: We used cross-sectional data from a multicenter study in 407 stable mild-to-very severe COPD patients from Barcelona (Catalonia). Patients answered the COPD Assessment Test (CAT) and Clinical COPD Questionnaire (CCQ). Individual residential exposure to air pollutants (nitrogen dioxide [NO₂] and particulate matters of varying aerodynamic diameters [PM_2.5, PM₁₀, and PM_{2.5absorbance}]), road traffic noise (L_den), and land surface temperature were estimated using long-term averages from land-use regression models, 24-h noise maps, and land surface temperature maps, respectively. We measured residential distances to blue/green spaces from the Urban Atlas. We used mixed-effect negative binomial (for CAT) and linear (for CCQ) regression models, adjusted for potential confounders, with a random effect by center.

Results: Of those patients, 85 % were male and had a mean (SD) age of 69 (9) years, CAT score of 12 (7), CCQ-total score of 1.4 (1.0), and post-bronchodilator forced expiratory volume in 1 s (FEV₁) of 57 (18) %predicted. We found that NO₂ and PM_{2.5absorbance} were associated with worsened CAT and CCQ-mental scores, e.g., 0.15-unit change in CAT score [regression coefficient (β) = 0.15; 95 % confidence interval (CI) = 0.03, 0.26] per interquartile range in NO₂ [13.7 μg/m³]. Greater distances to blue/green spaces were associated with worsened CCQ-mental scores [0.08; 0.002, 0.15].

Conclusions: Our study showed that increased air pollution, particularly NO₂ and PM_{2.5absorbance} and greater distances to blue/green spaces negatively influence HRQL in COPD patients. These findings have important implications for the WHO promotion to develop healthy cities for our future.

Keywords: Air pollution; Airflow limitation; COPD; Environment; Quality of life.