Cancer in glass workers: a systematic review and meta-analysis

Due to a potential exposure to several definite or probable carcinogens, the IARC classified manufacturing of art glass, glass containers, and pressed ware as probably carcinogenic to humans in 1993 (Group 2A). Purpose of this study was to update the evidence from recently published scientific reports. We searched for peer-reviewed articles published between 1993 and 2018 and combined result in terms of a meta-analysis. Overall, we considered twelve articles for a meta-analytic approach published after 1992. From a meta-analysis we derived a standardized incidence ratio (mSIR) and a standardized mortality ratio (mSMR) for lung cancer in men of 1.25 (95% CI 0.97–1.59) and 1.41 (95% CI 1.11–1.77), respectively. The estimated odds ratio (mOR) from five case–control studies was 1.25 (95% CI 0.90–1.73). Associated with an employment in glass factories, the estimated mSMR for larynx cancer was 2.38 (95% CI 1.23–4.16) based on two cohort studies; the mOR from four case–control studies was 1.35 (95% CI 0.73–2.52). Reports on elevated cancer risks at other sites were not consistent. Only few studies assessed cancer risk solely in glass workers. Gained evidence from more recent reports supports the IARC rating from 1993. Our combined results add limited evidence to a moderately elevated risk for cancer of the airways.