A cohort study ofworkers exposed toformaldehyde intheBritish chemical industry: an update

A cohortstudyof workersexposedto formaldehyde intheBritish chemical industry inany one ofsixfactories hasbeenextended aftertheearlier published reportin1984.A further eight years offoliow up totheendof 1989havebeenincluded fortheoriginally reported 7660workersfirst employedbefore 1965, anda first follow up tothesame datehas been carriedout for6357workersfirst employedsince1964.Extensive checking of thedatabase hastakenplaceincluding records at thefactories, theMRC Environmental Epidemiology Unit,andtheNational Health ServiceCentralRegister. The updatedfindingsinclude one deathfrom nasalcancer comparedwith1*7expected inthisnumberof men duringthefollow up period-which gives no supporttotheoriginal hypothesis basedon animal experimental datathatformaldehyde may bea nasalcarcinogen inhumans.There havebeenno cases ofnasopharyngeal cancer inthecohortcomparedwithan estimated 1-3 expected-which gives no supporttothefindingsin a similarly designedstudyin the UnitedStatesofan excess ofcancers ofthe nasopharynxassociated with exposure to formaldehyde. Therehasbeena slight excess ofabout12%forlungcancer with402deaths comparedwithabout359expected. Thisis similar to thatfoundintheUnitedStates study,buthigherthanwe reported earlier beforethechecking procedures andextended foliow up. Furtheranalysis gives no definitive indication ofthisexcess oflungcancer being clearly related toformaldehyde exposure, and theincrease iswithinthatgenerally thought