P-125 Telomere Shortening and Occupational Exposure to Benzene: A Multicenter Study

Introduction A recent study (doi:10.1016/j.envint.2021.106871) examined markers of biological aging among subjects occupationally exposed to benzene and found increased age acceleration and reduced telomere length (TL), especially in workers exposed to levels >10 ppm. We verified the same hypothesis on a larger study population characterized by a broader range of (lower) exposure levels. Methods We measured TL by real-time PCR in blood DNA from 373 individuals from occupational groups with heterogeneous benzene exposure and 102 referents from two Italian (Genoa, Milan) and one Bulgarian (Burgas) cities. Airborne benzene was measured using personal passive samplers. We used multivariate linear regression models to assess the association between benzene and TL and obtain adjusted TL geometric means (GM) and 95% Confidence Intervals (CI). Results Study participants were mostly males (86%) with a mean age of 38.8 years. Benzene levels were 0.0009-0.02ppm in Genoa, 0.0006-0.15ppm in Milan, 0.01-20.8ppm in Burgas, where 48 subjects had levels >0.5ppm, and only four >10ppm. Adjusted TL GM was 0.84 (95%CI: 0.80; 0.88) in subjects with benzene levels ≤0.005ppm, 0.83 (0.79; 0.86) in exposure category 0.005-0.01ppm, 0.80 (0.76; 0.84) in exposure category 0.01-0.05ppm, and 0.76 (0.72; 0.80) in those with levels >0.05ppm (p-trend=0.007). For a tenfold increase in benzene concentration, we estimated a decrease in TL (percent change) of -4.3 (-6.9; -1.6, p=0.002). Discussion Our results, although preliminary, are coherent with the available body of evidence and suggest that benzene might accelerate biological aging even at low exposure levels. Conclusion We will implement our analysis estimating biological age also through epigenetic clocks.