DNA damage in children exposed to secondhand cigarette smoke and its association with oxidative stress.

OBJECTIVE To compare oxidative status, total antioxidant capacity and values of DNA damage in peripheral blood lymphocytes in children exposed to secondhand cigarette smoke with healthy controls. DESIGN Analytical, Observational. PARTICIPANTS 54 children without any chronic diseases, attending the healthy child monitoring polyclinic. These comprised 27 children who had been exposed to passive cigarette smoke and 27 children who had not been exposed to cigarette smoke. MAIN OUTCOME MEASURES Urine cotinine levels by the chemiluminescent technique; DNA damage by alkaline comet assay; and total oxidant status (TOS) using a novel automated measurement method. RESULTS The mean urine cotinine, TOS, Oxidative Stress Index (OSI) and DNA damage values of the group exposed to cigarette smoke were determined to be at significantly higher level compared to the group not exposed to cigarette smoke (P<0.001). No statistically significant difference was determined in the TAS level between the two groups (P=0.1) CONCLUSIONS The results showed that TOS levels, OSI index and DNA damage in peripheral blood lymphocytes were significantly higher in children exposed to secondhand cigarette smoke than in those not exposed to secondhand cigarette smoke.