title: Assessment of micronuclei in lymphocytes from workers exposed to vapours and aerosols of bitumen.
abstract: We investigated the micronucleus frequencies in peripheral blood lymphocytes of 225 mastic asphalt workers (age 17-62 years) and 69 non-bitumen-exposed road construction workers (age 18-64 years) in Germany before and after the working shift. Median shift exposure to vapours and aerosols of bitumen of exposed workers was 3.0 mg/m³. Micronuclei (MN) were determined with a standard method using cytochalasin B. Median MN frequency was 6.0 (interquartile range (IQR) 4.0-8.5) MN/1,000 binucleated lymphocytes (MN/1,000 BNC) in exposed workers and 6.0 (IQR 4.0-8.3) MN/1,000 BNC in non-exposed workers before shift. After shift, we observed 6.5 (IQR 4.4-9.3) MN/1,000 BNC in exposed workers and 6.5 (IQR 4.0-9.0) MN/1,000 BNC in non-exposed workers. Regression models were applied with the log-transformed MN frequency as the dependent variable in order to estimate the effects of exposure to vapours and aerosols of bitumen and of potential confounders. Age was the strongest predictor of MN formation in both exposed workers and referents. Our data suggest that MN formation was not associated with concentration of vapours and aerosols of bitumen during shift at the individual level. Although similar MN frequencies were observed in both groups, the modelling of factors potentially influencing MN frequency revealed a weak group difference in the post-shift model. We conclude that this small difference cannot be judged to be a relevant mutagenic effect of exposure to vapours and aerosols of bitumen, also with regard to the lack of adjustment for multiple testing and the lack of a group effect in the original data.
authors.affiliation: Institute for Prevention and Occupational Medicine of the German Social Accident Insurance, Institute of the Ruhr-University Bochum (IPA), Bürkle-de-la-Camp-Platz 1, 44789 Bochum, Germany. welge@ipa-dguv.de
authors.forename: Peter
authors.initials: P
authors.lastname: Welge
authors.forename: Boleslaw
authors.initials: B
authors.lastname: Marczynski
authors.forename: Monika
authors.initials: M
authors.lastname: Raulf-Heimsoth
authors.forename: Anne
authors.initials: A
authors.lastname: Spickenheuer
authors.forename: Benjamin
authors.initials: B
authors.lastname: Kendzia
authors.forename: Evelyn
authors.initials: E
authors.lastname: Heinze
authors.forename: Jürgen
authors.initials: J
authors.lastname: Angerer
authors.forename: Heiko U
authors.initials: HU
authors.lastname: Käfferlein
authors.forename: Beate
authors.initials: B
authors.lastname: Pesch
authors.forename: Thomas
authors.initials: T
authors.lastname: Brüning
mesh_terms: D000293:Adolescent; D000328:Adult; D000336:Aerosols; D000395:Air Pollutants, Occupational / Q000378:metabolism / Q000633:toxicity*; D003430:Cross-Sectional Studies; D004784:Environmental Monitoring; D006801:Humans; D006838:Hydrocarbons / Q000378:metabolism / Q000633:toxicity*; D019570:Inhalation Exposure; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000473:pathology; D008297:Male; D048629:Micronuclei, Chromosome-Defective / Q000139:chemically induced; D015162:Micronucleus Tests; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects*; D011084:Polycyclic Aromatic Hydrocarbons / Q000032:analysis; D018570:Risk Assessment; D014835:Volatilization; D055815:Young Adult
chemical_list: D000336:Aerosols; D000395:Air Pollutants, Occupational; D006838:Hydrocarbons; D011084:Polycyclic Aromatic Hydrocarbons; C006647:asphalt