Asthmatic symptoms in schoolchildren: effect of PM_2.5 exposure, oxidative stress, and lung function growth.

Abstract

This study evaluated the longitudinal effects of annual PM_2.5 exposure on asthma symptoms, lung function growth, oxidative stress, and airway inflammation in adolescents. A cohort of 1494 adolescents (mean age 12 years) were prospectively followed from 2016 to 2018. Data included spirometry, fractional exhaled nitric oxide (FENO), and self-reported asthma symptoms. Annual PM_2.5 exposure was estimated using land-use regression models based on residential and school addresses. Biomarkers such as serum 8-hydroxy-2'-deoxyguanosine (8-OHdG), periostin, and allergen-specific IgE were analyzed. Each 1 μg/m³ increase in annual PM_2.5 exposure was associated with increased odds of current wheezing (OR = 1.18, 95% CI = 1.06-1.32), reduced lung function growth with lower FEV₁ (-12 ml) and FEF₂₅₋₇₅ (-25 ml/s), and elevated FENO levels (+0.278 ppb, P < 0.05). High serum 8-OHdG was associated with current wheezing (OR = 1.09, 95% CI = 1.02-1.17) and impaired lung function (P < 0.05). Annual PM_2.5 exposure positively correlated with 8-OHdG levels (r = 0.197, P < 0.001). PM_2.5 exposure adversely impacts respiratory health during adolescence, partly through oxidative stress. Pediatric environmental interventions and the use of oxidative stress biomarkers in clinical settings are crucial to reducing long-term pulmonary risks. This longitudinal study demonstrates that long-term PM_2.5 exposure is associated with increased asthmatic symptoms, elevated oxidative stress, and reduced lung growth in schoolchildren. Each 1 μg/m³ increase in annual PM_2.5 exposure is associated with higher odds of current wheezing, reduced FEV1 and FEF_25-75, elevated serum 8-OHdG levels, and increased FENO levels in school-aged adolescents.