Formaldehyde, FeNO and oxidative stress in traffic policemen working in two cities of northern Italy

Introduction. The relationship between exposure to formaldehyde (FA) air pollution and induction of inflammation and oxidative stress is still to deepen. Methods. This study enrolled 154 traffic policemen working, 109 in Turin (896.773 inhabitants, density per km2: 6.890) and 45 in Pavia (72.205 inhabitants, density per km2: 1.149), both located in the Po Valley, northern Italy. To each subjects a questionnaire was administered and each of them wore a personal sampler to measure air FA for a whole working shift at the end of which a spot of urine was collected to measure 15-F2t-isoprostane (15-F2t-isop) and cotinine as biomarkers of oxidative stress and of tobacco smoke respectively. Finally, FeNO was measured to each subject. Results. FA was 30.1 µg/m3 in Turin and 17.5 in Pavia; FeNO was 37.7 ppb in Turin and 33.6 in Pavia; 15-F2t-Isop was 4.425 ng/mg of crea in Turin and 4.142 in Pavia. Nevertheless, the mean of log FA in Turin (adjusted for covariates by means of multiple regression) was +3.37984 (C.I. 95% 3.329382–3.430297); it proved to be significantly higher (p<0.000) than that of Pavia, +2.843968 (C.I. 95% 2.765186–2.922749). The same difference between the two cities (p<0.000) was highlighted for log FeNO: adjusted mean 3.421541 (C.I. 95%, 3.282263–3.560818) in Turin and 2.965183 (C.I. 95% 2.748418- 3.181947) in Pavia. Overall, FA significantly correlates (p<0.000) with 15-F2t-isop (regression coeff. +0.7356129, C.I. 95% 0.3696074-1.101618) but, adjusted for FA, 15-F2t-isop is significantly higher (p<0.000) in Pavia (means +1.653143, C.I. 95% 1.42705–1.879235) than in Turin (mean 0.9803417, C.I. 95% 0.8521908–1.108493). Conclusion. FA is higher in Turin, more densely populated, as well as FeNO but not 15-F2t-Isop. Probably, the relationship showed between air-FA and inflammation quantified by FeNO is direct, while the oxidative stress showed by15-F2t-isop is systemic and then in Pavia may depend on other not investigated factors.