Odds for COPD in young population increase with ozone, household air pollution exposure
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Key takeaways:
- Young individuals with household air pollution exposure or ambient ozone exposure had a higher likelihood for COPD.
- Exposure to both pollutants raised the odds for COPD.
Individuals aged 15 to 50 years faced heightened odds for COPD if they had been exposed to household air pollution and elevated ambient ozone levels, according to results published in Thorax.
“Ambient [ozone (O3)] and [household air pollution] were identified as major preventable risk factors for COPD,” Zhenzhen Xing, MD, of the department of respiratory and critical care medicine at Beijing Hospital and Peking University Fifth School of Clinical Medicine, and colleagues wrote. “In particular, there may be a synergistic interaction between O3 and [household air pollution] on the effect of COPD in young individuals in the study population.”
In a population-based study in western China, Xing and colleagues assessed 6,537 individuals (mean age, 33.39 years; 49.8% male) aged 15 to 50 years living in low- and middle-income regions to find out how exposure to ambient O3 and household air pollution are linked to COPD through multivariable logistic regression models.
Of the total cohort, 511 individuals (mean age, 37.17; 51.5% male) had COPD, whereas the remaining 6,026 individuals (mean age, 33.07 years; 49.7% male) did not. Overall COPD prevalence was 7.8% (95% CI, 7.2%-8.5%), with greater prevalence as individuals aged, according to researchers.
Researchers found patients with vs. without COPD had a higher BMI (24.28 kg/m2 vs. 23.89 kg/m2; P = .036), a greater prevalence of small airway dysfunction (84.2% vs. 30.3%; P < .001) and a history of asthma (4.7% vs. 3%; P = .043).
In terms of lung function, patients with COPD had poorer measures than those without COPD across several parameters both before and after receiving a bronchodilator.
Following adjustment for confounding variables, researchers found that the odds for COPD in this patient population went up with exposure to household air pollution (OR = 1.82; 95% CI, 1.41-2.37) and with each 20 ppb rise in interquartile range (IQR) for O3 (OR = 1.92; 95% CI, 1.59-2.32).
Combining the two exposures demonstrated an even higher likelihood for COPD, with an odds ratio of 3.94 (95% CI, 2.53-6.41) among individuals with exposure to household air pollution and at least 78 ppb O3 vs. individuals with no exposure to household air pollution and O3 exposure less than 58 ppb.
Both male sex (OR = 1.3; 95% CI, 1.03-1.63) and age (OR = 1.58; 95% CI, 1.41-1.76) also significantly heightened the odds for COPD, according to researchers.
In an additive interactions analysis that controlled for several variables, researchers found that the individual effect of household air pollution on COPD prevalence was 1.68 (95% CI, 1.18-2.46), whereas the effect of O3 on prevalence was 1.55 (95% CI, 0.99-2.43).
Notably, the effect went up to 3.28 (95% CI, 2.35-4.69) when both air pollutants were considered with a relative excess risk based on interaction of 1.05 (95% CI, 0.33-1.78), according to researchers.
“The prevalence of COPD in young people is no longer negligible,” Xing and colleagues wrote. “Enhancing prevention and control of air pollution (including ozone and household air pollution) should be considered public health priorities in low-income and middle-income regions.”