Air Pollution Exposures And Micronuclei Frequencies In Lymphocytes From Pregnant Women And Newborns (A Cohort Study)

Abstract

Introduction: Micronuclei (MN) are markers of pre-carcinogenic events and have been associated with cancer risk in adults. Few studies have examined MN frequencies in pregnant women and newborns. We examined MN frequency in maternal and cord blood in relation to air pollution exposure and the potential interaction with maternal intake of vitamin C and smoking in a mother-child cohort. Methods: We used the cytokinesis-block micronucleus assay to assess MN frequencies in binucleated T-lymphocytes (MNBN) from 181 mothers and 183 newborns born in 2007-2008. The ESCAPE land-use regression methods were used to estimate annual mean exposure to outdoor air pollution at maternal home addresses. Food frequency questionnaires were used to estimate maternal dietary and vitamin C intake. Smoking habits were assessed through self-administrated questionnaires. Results: We found increased frequency of MNBN in mothers in relation to exposure to particulate matter (PM) with an aerodynamic diameter <2.5μm exposure (PM2.5), with an adjusted incidence rate ratio [IRR (95%CI)] per 5µg/m3 of 1.53 (1.02, 2.29). MMBN frequencies were considerably higher among women who did not fulfil the recommended vitamin C intake dietary allowances [IRR=9.35 (2.77, 31.61); n=20]. Exposure to PM2.5-10, PM10, NO2 and NOx were also associated with higher MNBN incidence among smoking women [PM2.5-10: p-value interaction=0.036, IRR smokers=1.4 (0.94, 2.05); PM10: p-value interaction=0.017, IRR smokers=2.33 (1.16, 4.67); NO2: p-value interaction=0.001, IRR smokers=1.62 (1.06, 2.47) and NOx: p-value interaction=0.001, IRR smokers=1.46 (1.08, 1.96); n=56]. No associations were found for newborns. Conclusions: We detected an association between air-pollution, and particularly PM2.5, and MNBN in mothers but not in newborns. This association with air-pollution seemed to be modified by maternal smoking and low dietary intake of vitamin C during pregnancy.