Scarnato C, Rambaldi R, Mancini G, Olanda S, Spagnolo MR, Previati E, Parmeggiani V, Minisci S, Comba P, Pirastu R. [Mortality study update of workers exposed to vinyl chloride in plants located in Ferrara and Ravenna (Emilia-Romagna Region, Northern Italy)].
Epidemiol Prev 2018;
41:271-278. [PMID:
29119762 DOI:
10.19191/ep17.5-6.p271.088]
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Abstract
OBJECTIVES
to update the mortality study of subjects exposed to vinyl chloride in the phases of synthesis of the monomer and polymerization in the plants of Ferrara and Ravenna (Emilia-Romagna Region, Northern Italy).
DESIGN
both for the whole cohort and for the two plants, standardized mortality ratios (SMRs), with 95% confidence intervals (95%CI), were calculated for different death causes, then stratified by duration and latency, periods of the beginning of work and cumulative exposure (ppm-years).
SETTING AND PARTICIPANTS
the cohort includes 1,540 subjects (469 in Ferrara hired from 1953 to 1999; 1,071 in Ravenna hired from 1959 to 2000), with at least six months of work.
RESULTS
by the end of the follow-up (31.12.2013), 348 deaths occurred. Overall observed mortality, contrasted to that expected based on Emilia-Romagna Region mortality rates, appeared to be lower than expected in the whole cohort (348 cases, SMR: 0.85; 95%CI 0.77-0.95) and in Ravenna (173 cases, SMR: 0.71; 95%CI 0.61-0.83). Mortality for all neoplasms was in excess in Ferrara (79 cases, SMR: 1.27; 95%CI 1.02-1.58), but lower than expected in Ravenna (83 cases, SMR: 0.80; 95%CI 0.64-0.99). An excess in mortality was observed in the whole cohort (16 cases, SMR: 1.74; 95%CI 1.07-2.85) and in Ferrara for liver cancer (7 cases, SMR: 2.12; 95%CI 1.02-4.46), and only in Ferrara for respiratory tract cancer (30 cases, SMR: 1.45; 95%CI 1.02-2.07) and larynx cancer (4 cases, SMR: 3.35; 95%CI 1.26-8.92). In the whole cohort, SMR for liver cancer was in excess since a cumulative exposure of 5,000 ppm-year and 12 cases belong to the job title of autoclave workers (12 cases, SMR 4.6; 95%CI 2.6-8.0), duration of work higher than 20 years (8 cases, SMR 2.4; 95%CI 1.2-4.9), and latency higher than 40 years (7 cases, SMR 2.5; 95%CI 1.2-5.2). The excess in mortality for lung cancer is statistically significant for and with cumulative exposure higher than 7,330 ppm-years (6 cases, SMR 3.2 95%CI 1.4-7.0). There are not excesses among subjects hired after 1971.
CONCLUSIONS
the study findings confirm and expand the ones of previous studies. It was not possible to apply a best evidence approach to the study of liver cancer, and consequently it is not possible to distinguish between hepatic angiosarcoma and hepatocellular carcinoma. The evidence of a causal link between vinyl chloride exposure and liver cancer is anyhow confirmed. The causal link between vinyl chloride exposure and lung cancer must be further investigated.
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