title: The cytokinesis-block micronucleus (CBMN) assay in human populations exposed to styrene: A systematic review and meta-analysis.
abstract: Styrene is a building-block of several compounds used in a wide array of materials and products. The most important human exposure to this substance occurs in industrial settings, especially among reinforced-plastics industry workers. The effect of occupational exposure to styrene on cytogenetics biomarkers has been previously reviewed with positive association observed for chromosomal aberrations, and inconclusive data for the micronucleus assay. Some limitations were noted in those studies, including inadequate exposure assessment and poor epidemiological design. Furthermore, in earlier studies micronuclei frequency was measured with protocols not as reliable as cytokinesis-block micronucleus (CBMN) assay. Aim of the present systematic review and meta-analysis is to investigate genomic instability and DNA damage as measured by the CBMN assay in lymphocytes of subjects exposed to styrene. A total of 11 studies published between 2004 and 2012 were included in the meta-analysis encompassing 479 styrene-exposed workers and 510 controls. The quality of each study was estimated by a quality scoring system which ranked studies according to the consideration of major confounders, exposure characterization, and technical parameters. An overall increase of micronuclei frequencies was found in styrene-exposure workers when compared to referents (meta-MR 1.34; 95% CI 1.18-1.52), with significant increases achieved in six individual studies. The consistency of results in individual studies, the independence of this result from major confounding factors and from the quality of the study strengthens the reliability of risk estimates and supports the use of the CBMN assay in monitoring genetic risk in styrene workers.
authors.affiliation: National Institute of Health, Environmental Health Department, Rua Alexandre Herculano, 321, 4000-055 Porto, Portugal; EPIUnit - Institute of Public Health, University of Porto, Rua das Taipas, 135, 4050-600 Porto, Portugal. Electronic address: solange.costa2@gmail.com.
authors.forename: Solange
authors.initials: S
authors.lastname: Costa
authors.affiliation: Unit of Clinical Epidemiology, IRCCS AUO San Martino-IST, Largo Rosanna Benzi 10, 16132 Genoa, Italy.
authors.forename: Marcello
authors.initials: M
authors.lastname: Ceppi
authors.affiliation: National Institute of Health, Environmental Health Department, Rua Alexandre Herculano, 321, 4000-055 Porto, Portugal; EPIUnit - Institute of Public Health, University of Porto, Rua das Taipas, 135, 4050-600 Porto, Portugal.
authors.forename: Carla
authors.initials: C
authors.lastname: Costa
authors.affiliation: National Institute of Health, Environmental Health Department, Rua Alexandre Herculano, 321, 4000-055 Porto, Portugal.
authors.forename: Susana
authors.initials: S
authors.lastname: Silva
authors.affiliation: National Institute of Health, Environmental Health Department, Rua Alexandre Herculano, 321, 4000-055 Porto, Portugal; EPIUnit - Institute of Public Health, University of Porto, Rua das Taipas, 135, 4050-600 Porto, Portugal.
authors.forename: Cristiana
authors.initials: C
authors.lastname: Pereira
authors.affiliation: DICOMOSA Group, Department of Psychology, Area of Psychobiology, Universidade da Coruña, Research Services Building, Campus Elviña s/n, 15071 A Coruña, Spain.
authors.forename: Blanca
authors.initials: B
authors.lastname: Laffon
authors.affiliation: Unit of Clinical and Molecular Epidemiology, IRCCS San Raffaele Pisana, Via di Val Cannuta, 247, 00166 Roma, Italy; Department of Human Sciences and Quality of Life Promotion, San Raffaele University, Via di Val Cannuta, 247, 00166 Roma, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Bonassi
authors.affiliation: National Institute of Health, Environmental Health Department, Rua Alexandre Herculano, 321, 4000-055 Porto, Portugal; EPIUnit - Institute of Public Health, University of Porto, Rua das Taipas, 135, 4050-600 Porto, Portugal.
authors.forename: João Paulo
authors.initials: JP
authors.lastname: Teixeira
mesh_terms: D016022:Case-Control Studies; D048749:Cytokinesis / Q000187:drug effects*; D006801:Humans; D015162:Micronucleus Tests / Q000379:methods*; D016273:Occupational Exposure; D020058:Styrene / Q000633:toxicity*
chemical_list: D020058:Styrene
keywords: CBMN assay; Human exposure; Meta-analysis; Micronuclei; Styrene; Systematic review