Meta-analyses of occupational exposure as a painter and lung and bladder cancer morbidity and mortality 1950–2008

Abstract

The International Agency for Research on Cancer (IARC) classified occupational painting as a human carcinogen based on lung and bladder cancers; however, no specific exposures were implicated. The authors conducted comprehensive meta-analyses of the epidemiological literature on occupational painting and these cancers. The authors abstracted study results and confounder information, and used quantile plots and regression models to evaluate heterogeneity and publication bias. Summary risk estimates were derived and sensitivity analyses performed to evaluate smoking, socioeconomic status (SES), and exposure variables. Where applicable, a Bayesian approach was used to externally adjust for smoking, a major risk factor for both cancers. For lung cancer cohort mortality studies, publication bias and heterogeneity were seen, and earlier studies reported higher risk estimates than later studies. Overall lung cancer summary risk estimates were 1.29 for case-control and 1.22 and 1.36 for cohort morbidity and mortality studies, respectively, and risk estimates for bladder cancer were 1.28 for case-control and 1.14 and 1.27 for cohort morbidity and mortality studies, respectively (all statistically significant). Risks did not differ between painters and mixed occupations. Nonsignificant summary estimates resulted for lung and bladder cancers when controlling for SES, or externally adjusting for smoking in lung cancer studies. Summary risks varied by control source for case-control studies. Residual confounding by smoking and SES, lack of exposure group effect, and publication bias limit the ability of the meta-analyses to explain associations observed between occupational painting and lung and bladder cancers. Given the long latencies for lung and bladder cancers, these weak associations, if real, may not be elucidated through studies of occupational painting today.

Contemporary Occupational Carcinogen Exposure and Bladder Cancer

“…Highspeed rotating presses released an ink mist rich with these carcinogens, which was subsequently linked to lung and BC. 33 Other printing exposures include 4-aminodiphenyl (4-ADP) as a metabolite of induline/nigrosine dyes (mostly replaced in the 1970s 36 The main carcinogen for hairdressers is reported to be 4-ABP. This agent has been restricted since the 1970s, and consequently BC risk has fallen from 3.2-to 9.15-fold 37,38 to 1.23-to 1.32-fold (eTable 4 in the Supplement or Reulen et al 4 ).…”

Occupational and Environmental Causes of Lung Cancer

“…A 2010 meta-analysis based on census reports, and case-control and cohort studies published through 2008, 86 reported a summary risk estimate for lung cancer among painters of 1.29 (95% CI 1.10–1.51) for case-control studies and 1.22 (95% CI 1.16–1.29) and 1.36 (95% CI 1.34–1.41) for lung cancer incidence and mortality studies, respectively. A second large meta-analysis published in 2010, 87 which included more than 11,000 incident lung cancer cases or deaths among painters, reported a summary risk estimate for lung cancer of 1.35 (95% CI 1.29–1.41) and 1.35 (95% CI 1.21–1.51) after controlling for smoking.…”

Bladder cancer risk in painters

“…The meta-analysis by Bachand et al 3 is, however, much less clear. Although it essentially comes to very similar conclusions (an overall risk estimate of 1.23 for bladder cancer), the paper is unfortunately rather confusing.…”

“…Another meta-analysis has been recently published, that covers most (but not all) of the studies included in the report under discussion 3. The meta-analysis by Bachand et al 3 is, however, much less clear.…”