Vol. 70, Iss. 12, December 2013
Cholangiocarcinoma among workers in the printing industry: using the NOCCA database to elucidate the generalisability of a cluster report from Japan
Riassunto
Objectives A cluster of 11 cases of cholangiocarcinoma (CC) was observed in a small Japanese printing firm. To elucidate whether the identified cluster is indicative of an elevated risk of CC among workers in the printing industry at large, we explored the risk of cancer of the liver and CC among individuals employed in the printing industry in a large cohort set-up in four Nordic countries (Finland, Iceland, Norway and Sweden) over a period of 45 years.
Methods The cohort was set-up by linking occupational information from censuses to national cancer registry data utilising personal identity codes in use in all Nordic countries. We calculated standardised incidence ratios (SIRs) for men and women working in the printing industry, and stratified by occupational category (typographers, printers, lithographers, bookbinders).
Results Among men, we observed elevated SIRs for cancer of the liver (1.35, 95% CI 1.14 to 1.60; 142 cases), specifically intrahepatic CC (2.34, 95% CI 1.45 to 3.57; 21 cases). SIRs for liver cancer were especially elevated among printers and lithographers, and SIRs for intrahepatic CC among typographers and printers. SIRs for extrahepatic CC were not elevated. SIRs for women followed a similar pattern but the number of cases was low.
Conclusions Our study supports the notion that the finding of excess CC risk among workers in a small Japanese printing firm possibly extends beyond this specific firm and country. Further studies should focus on the specific exposures that occur in the printing industry.
Commento
Il presente studio, di Vlaanderen e collaboratori, ci fornisce un interessante esempio di come un database di morbilità/mortalità possa essere utilizzato al fine di ampliare le conoscenze scientifiche inerenti le patologie professionali.
Il “Nordic Occupational Cancer Study” (NOCCA) è una delle più grandi ricerche di coorte basate su popolazioni lavorative e comprende circa 15 milioni di persone registrate, in un arco di 45 anni, nei censimenti di Danimarca, Finlandia, Islanda, Norvegia e Svezia. Le ragguardevoli dimensioni della coorte rendono il NOCCA particolarmente adatto allo studio di patologie carcinomatose rare e all’individuazione dei potenziali rischi professionali.
Riprendendo i risultati di una ricerca di particolare interesse pubblicata recentemente da Kumagai e collaboratori su ”Occupational and environmental medicine” (numero di Luglio 2013), lo studio di Vlaanderen si propone di utilizzare il NOCCA al fine di esaminare le eventuali relazioni esistenti tra le esposizioni chimiche di natura professionale e lo sviluppo di tumori epatici e delle vie biliari, in lavoratori dell’industria della stampa.