Asthmatic symptoms in schoolchildren: effect of PM2.5 exposure, oxidative stress, and lung function growth.

BACKGROUND

This study evaluated the longitudinal effects of annual PM2.5 exposure on asthma symptoms, lung function growth, oxidative stress, and airway inflammation in adolescents.

METHODS

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 PM2.5 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.

RESULTS

Each 1 μg/m³ increase in annual PM2.5 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 PM2.5 exposure positively correlated with 8-OHdG levels (r = 0.197, P < 0.001).

CONCLUSIONS

PM2.5 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.

IMPACT: This longitudinal study demonstrates that long-term PM2.5 exposure is associated with increased asthmatic symptoms, elevated oxidative stress, and reduced lung growth in schoolchildren. Each 1 μg/m³ increase in annual PM2.5 exposure is associated with higher odds of current wheezing, reduced FEV1 and FEF25-75, elevated serum 8-OHdG levels, and increased FENO levels in school-aged adolescents.