Abstract
With the rationale that the oxidative potential of particulate matter (PM-OP) may induce oxidative stress and inflammation, we conducted the ASTHMA-FENOP study in which 44 asthmatic patients and 37 matched controls wore a personal sampler for 24 h, allowing the collection of fine and coarse PM fractions separately, to determine PM-OP by the dithiothreitol (DTT) and ascorbic acid (AA) methods. The levels of Interleukin 6 (IL-6) and the IL-6/IL-10 ratio, as indicators of pro- and anti-inflammatory statuses, were determined by calculating the mean differences (MDs), odds ratios (ORs) and p-trends adjusted for sex, age, study level and body mass index. Positive associations for IL-6 levels in the form of adjusted MDs and ORs were obtained for all PM-OP metrics, reaching statistical significance for both OP-DTT and OP-AA in the fine fraction, with adjusted OR = 5.66; 95%CI (1.46 to 21.92) and 3.32; 95%CI (1.07 to 10.35), respectively, along with statistically significant dose-response patterns when restricting to asthma and adjusted also for clinical variables (adjusted p-trend = 0.029 and 0.01). Similar or stronger associations and dose-response patterns were found for the IL-6/IL-10 ratio. In conclusion, our findings on the effect of PM-OP on systemic inflammation support that asthma is a heterogeneous disease at the molecular level, with PM-OP potentially playing an important role.