DNA bulky adducts in a Mediterranean population correlate with environmental ozone concentration, an indicator of photochemical smog

Abstract

1 Ozone (O 3 ), the major oxidant component in photochemical smog, mostly derives from photolysis of nitrogen dioxide. O 3 may have biologic effects directly and/or via free radicals reacting with other primary pollutants and has been reported to influence daily mortality and to increase lung cancer risk. Although DNA damage may be caused by ozone itself, only other photochemical reaction products (as oxidised polycyclic aromatic hydrocarbons) may form bulky DNA adducts, a reliable biomarker of genotoxic damage and cancer risk, showing a seasonal trend. In a large series consisting of 320 residents in the metropolitan area of Florence, Italy, enrolled in a prospective study for the period 1993-1998 (206 randomly sampled volunteers, 114 traffic-exposed workers), we investigated the correlation between individual levels of DNA bulky adducts and a cumulative O 3 exposure score. The average O 3 concentrations were calculated for different time windows (0 -5 to 0 -90 days) prior to blood drawing for each participant, based on daily measurements provided by the local monitoring system. Significant correlations between DNA adduct levels and O3 cumulative exposure scores in the last 2-8 weeks before enrollment emerged in never smokers. Correlations were highest in the subgroup of never smokers residing in the urban area and not occupationally exposed to vehicle traffic pollution, with peak values for average concentrations 4 -6 weeks before enrollment (r ‫؍‬ 0.34). Our current findings indicate that DNA adduct formation may be modulated by individual characteristics and by the cumulative exposure to environmental levels of ozone in the last 4 -6 weeks, possibly through ozone-associated reactive pollutants.

DNA Adducts and Lung Cancer Risk: A Prospective Study

“…This is consistent with a previous investigation showing a relationship between cumulative O 3 exposure and DNA adduct formation among nonsmokers in Florence, Italy (34). O 3 is a marker of photochemical smog, being produced by a complex series of reactions involving hydrocarbons and nitrogen dioxide, emitted primarily during combustion of fossil fuels by industry and transportation activities, and driven by UV radiation in sunlight (3).…”

Air pollution and risk of lung cancer in a prospective study in Europe

“…12 Therefore, it is not necessarily relevant, at least in causal assessment, to distinguish among single pollutants; rather, they might interact in unpredictable ways. O 3 has been found to damage DNA in 2 epidemiological studies, including the present one, 13,14 but its role is more difficult to assess because of strong negative association with other 2 , 27 vs <27 lg/m 3 for PM10, and 11 vs <11 lg/m 3 for SO 2 (see text).-2 As in footnote 1 but additionally adjusted by BMI, education, intake of fruit and vegetables, intake of meat, intake of alcohol, physical activity.-3 As in footnote 1 but additionally adjusted by cotinine.- 4 As in footnote 1 but additionally adjusted by occupational index (see text).…”

Bulky DNA adducts and breast cancer risk in the prospective EPIC-Italy study

“…In a previous study carried out in the frame of EPIC-Florence study, by using the same method of DNA adducts detection ( 32 P-postlabelling), we reported a significant correlation between individual levels of bulky DNA adducts and the mean environmental levels of a specific air pollutant (ozone), measured in a period prior the blood drawing, in never-smokers residing in the Florence urban area and not occupationally exposed to vehicle traffic pollution [36]. The association between bulky DNA adducts and ozone concentration has been confirmed in a larger nested case-control study carried out in the frame of a larger European prospective study [25].…”