247 Mortality study in two Italian cohorts of workers exposed to PCBs: extension of the follow-up up to 2006

Objectives PCBs have been classified as carcinogenic in animals and probably carcinogenic to humans (IARC1987). Epidemiological studies showed increased risks for Non-Hodgkin’s Lymphoma, liver and biliary tract, digestive, skin, prostate and brain cancer but findings are still controversial. We present the results of the extension of the follow-up as of 2006 of two cohorts of workers potentially exposed to PCBs in capacitor manufacturing plants in Lombardy, Northern Italy. The mortality of the two cohorts was previously examined up to 1991 (Plant 1) and 2002 respectively (Plant 2). Methods The study population included 544 males and 1551 females employed between 1946 and 1978 in Plant 1 and 373 males and 97 females employed between 1950 and 1988 in plant 2. Standardised mortality ratios (SMR) and 95% Confidence Intervals (95% CI) were calculated (in the whole cohort, separately in plant 1 and 2 and among males and females) using as reference the regional mortality rates specific by age and calendar period. Results In the whole cohort, increased mortality from biliary tract and “other digestive” cancer, prostate, brain cancer, Hodgkin and non-Hodgkin lymphoma (8 deaths, SMR 1.65; 95% CI 0.8–3.3) were detected. The excess mortality from biliary tract cancer was confined to males (4 deaths, SMR 3.9; 95% CI 1.5–10.4), where as the increased mortality from Hodgkin lymphoma (4 deaths, SMR 3.6, 95% CI 1.3–9.5) and brain cancer (7 deaths, SMR 2.1; 95% CI 1.02–4.5) was observed in plant 1 only. The excess mortality from other digestive cancer and NHL was equally distributed in the two cohorts and among males and females. Analyses by duration of employment and time since first employment did not show consistent trends. Conclusions Our findings suggest increased mortality from cancers of “a priori” interest in PCB exposed workers, however these excesses were not clearly related to duration of employment and latency.