Influence of ambient air pollution on global DNA methylation in healthy adults: A seasonal follow-up

- %5mdC analyzed with HPLC in whole blood of 48 adults in winter and summer
- Lower %5mdC associated with various NO2, M10, PM2.5 and O3 moving average exposures
- Lower %5mdC associated with air pollutants in summer but not in winter
- Most effects observed for 5- to 30-day moving average exposures
- Effects observed in non-diseased adults at concentrations below EU guidelines

BackgroundDNA methylation changes are potential pathways of environmentally induced health effects. We investigated whether exposure to ambient concentrations of NO2, PM10, PM2.5 and O3 and traffic parameters were associated with global DNA methylation in blood of healthy adults.Methods48 non-smoking adults (25 males) with a median age of 39 years were sampled in winter and summer. Global DNA methylation in whole blood (% 5-methyl-2′-deoxycytidine, %5mdC) was analyzed with HPLC. Exposure to air pollutants at the home address was assessed using interpolated NO2, PM10, PM2.5 and O3 concentrations for various exposure windows (60- to 1-day moving average exposures and yearly averages) and GIS-based traffic parameters. Associations between pollutants and %5mdC were tested with multiple mixed effects regression models.ResultsAverage %5mdC (SD) was 4.30 (0.08) in winter and 4.29 (0.08) in summer. Men had higher %5mdC compared to women both in winter (4.32 vs. 4.26) and summer (4.31 vs. 4.27). When winter and summer data were analyzed together, various NO2, PM10 and PM2.5 moving average exposures were associated with changes in %5mdC (95% CI) ranging from − 0.04 (− 0.09 to 0.00) to − 0.14 (− 0.28 to 0.00) per IQR increase in pollutant. NO2, PM10, PM2.5 and O3 moving average exposures were associated with decreased %5mdC (95% CI) varying between − 0.01 (− 0.03 to 0.00) and − 0.17 (− 0.27 to − 0.06) per IQR increase in pollutant in summer but not in winter.ConclusionDecreased global DNA methylation in whole blood was associated with exposure to NO2, PM10, PM2.5 and O3 at the home addresses of non- adults. Most effects were observed for the 5- to 30-day moving average exposures.