(in German)

Polycyclic aromatic hydrocarbons (PAH) form during incomplete combustion. An increased risk of lung cancer caused by occupational exposure to PAH has been shown in numerous epidemiological studies, e.g. in the coke making industry, during the production of generator gas and aluminum, and among road pavers, roofers, and chimney sweeps. In 2009, "lung cancer caused by polycyclic aromatic hydrocarbons if there is evidence of exposure to a cumulative dose of at least 100 benzo[a]pyrene years [(microgramm/m3) x Years]" became occupational disease No. 4113 in the list of German occupational diseases. This systematic review provides needed scientific clarification regarding the association between occupational PAH exposure and larynx cancer.

A search of Medline and Embase with a search string including terms regarding PAH exposure as well as PAH exposed occupations and an extensive manual search of reference lists was used to collect relevant articles through the beginning of 2011. Title and abstract screening and assessment of the full texts for inclusion criteria and study quality through two independent reviewers followed. Random effects meta analysis of the extracted effect sizes were conducted with STATA.

Titles and abstracts from a total of 2.788 literature records were screened and 149 articles met the inclusion criteria. After exclusion of further studies during the full text screening, a total of 88 articles (21 with satisfactory (+), 67 with poor quality (-)) were included in the qualitative synthesis. Due to several publications with overlapping study populations, the subsequent meta analysis was conducted with the extracted results of 62 articles. Of these articles, 16 were judged to have a satisfactory (+) and 46 a poor (-) quality score.

The meta analysis resulted in a pooled effect size of 1.41 (95 % CI 1.30 1.53) for larynx carcinoma and occupational PAH exposure. The sub group analysis found no substantial difference between the effect sizes for incident larynx carcinoma and deaths due to larynx carcinoma. The study quality also had no substantial effect on the pooled effect sizes. Only very few studies allowed an investigation of the dose response relationship; these studies give indications of a positive dose response effect. The results of this present systematic review with meta analysis show a robust relationship between occupational PAH exposure and the diagnosis with larynx carcinoma.

Please download the complete report "Occupational Exposure to Polycyclic Aromatic Hydrocarbons and larynx cancer - a systematic review" (in German only).