Association between oxidative potential from particulate matter collected by personal samplers, and systemic inflammation in adult asthma patients. Preliminary results of ASTHMA-FENOP study.

<bold>Introduction:</bold> We aimed to determine whether exposure to particulate matter (PM), measured as the oxidative potential (OP) of filters collected from 24 hours personal samplers, is associated with increased inflammation in asthma patients. <bold>Methods:</bold> 42 patients were included, determining their OP by two methods: dithiothreitol (DTT) and ascorbic acid (AA). Serum Interleukin-6 (IL-6) and the IL-6/IL-10 levels as markers of inflammation were dichotomized based on the median, and OP levels were ordinal categorized (low T1, medium T2, high T3) according to tertiles, calculating adjusted odds ratios (aORs) and p trends, with sex, age, asthma control test, test of Adherence to Inhalers, asthma severity (spanish GEMA guideline steps) and body mass index as confounders. <bold>Results:</bold> A statistically significant dose-response pattern (p-trend=0.010) was found for OP-DTT in the fine fraction. The greater OP, the greater levels of IL-6: aOR for T2=35.83; aOR for T3=98.13. For AA method, a suggestive dose-response pattern was obtained (aOR for T2=1.43, aOR for T3=6.46, p trend=0.069). With regard to the coarse fraction, OP-DTT higher levels according to median were also associated: aOR=4.30, p=0.093. According to AA method, a positive non-significant aOR=2.22 was obtained. Associations and dose-response patterns were maintained for the ratio IL-6/IL-10 levels rather similar to IL-6 alone results. <bold>Conclusions:</bold> Effect of OP from PM on inflammation appears to be of considerable magnitude and with a dose pattern response at least for the OP of the fine fraction, suggesting causality.