title: Meta-Analysis of Cardiac Mortality in Three Cohorts of Carbon Black Production Workers.
abstract: Epidemiological studies have demonstrated associations between airborne environmental particle exposure and cardiac disease and mortality; however, few have examined such effects from poorly soluble particles of low toxicity such as manufactured carbon black (CB) particles in the work place. We combined standardised mortality ratio (SMR) and Cox proportional hazards results from cohort studies of US, UK and German CB production workers. Under a common protocol, we analysed mortality from all causes, heart disease (HD), ischemic heart disease (IHD) and acute myocardial infarction (AMI). Fixed and random effects (RE) meta-regression models were fit for employment duration, and for overall cumulative and lugged quantitative CB exposure estimates. Full cohort meta-SMRs (RE) were 1.01 (95% confidence interval (CI) 0.79-1.29) for HD; 1.02 (95% CI 0.80-1.30) for IHD, and 1.08 (95% CI 0.74-1.59) for AMI mortality. For all three outcomes, meta-SMRs were heterogeneous, increased with time since first and time since last exposure, and peaked after 25-29 or 10-14 years, respectively. Meta-Cox coefficients showed no association with lugged duration of exposure. A small but imprecise increased AMI mortality risk was suggested for cumulative exposure (RE-hazards ratio (HR) = 1.10 per 100 mg/m³-years; 95% CI 0.92-1.31), but not for lugged exposures. Our results do not demonstrate that airborne CB exposure increases all-cause or cardiac disease mortality.
authors.affiliation: Institute and Policlinic for Occupational Medicine, Environmental Medicine and Preventive Research, University of Cologne, Cologne 50937, Germany. peter.morfeld@evonik.com.|Institute for Occupational Epidemiology and Risk Assessment of Evonik Industries, Essen 45128, Germany. peter.morfeld@evonik.com.
authors.forename: Peter
authors.initials: P
authors.lastname: Morfeld
authors.affiliation: Health Sciences, Ramboll Environ, Amherst, MA 01002, USA. kmundt@environcorp.com.
authors.forename: Kenneth A
authors.initials: KA
authors.lastname: Mundt
authors.affiliation: Health Sciences, Ramboll Environ, Amherst, MA 01002, USA. ldell@environcorp.com.
authors.forename: Linda D
authors.initials: LD
authors.lastname: Dell
authors.affiliation: Institute of Occupational and Environmental Medicine, University of Birmingham, Birmingham B15 2TT, UK. T.M.Sorahan@bham.ac.uk.
authors.forename: Tom
authors.initials: T
authors.lastname: Sorahan
authors.affiliation: Massachusetts Institute of Technology, Cambridge, MA 02139, USA. mccunney@mit.edu.|Brigham and Women's Hospital, Boston, MA 02215, USA. mccunney@mit.edu.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: McCunney
mesh_terms: D000395:Air Pollutants, Occupational / Q000633:toxicity*; D015331:Cohort Studies; D005858:Germany / Q000453:epidemiology; D006331:Heart Diseases / Q000209:etiology / Q000401:mortality*; D006801:Humans; D009784:Occupational Diseases / Q000209:etiology / Q000401:mortality*; D016273:Occupational Exposure / Q000009:adverse effects*; D016016:Proportional Hazards Models; D053260:Soot / Q000633:toxicity*; D006113:United Kingdom / Q000453:epidemiology; D014481:United States / Q000453:epidemiology
chemical_list: D000395:Air Pollutants, Occupational; D053260:Soot
keywords: Cox regression; SMR; epidemiology; heart disease; ischemic heart disease; myocardial infarction; nanoparticles; occupation