OCCUPATIONAL EXPOSURE TO MACHINING FLUIDS AND LARYNGEAL-CANCER RISK -CONTRASTING RESULTS USING 2 SEPARATE CONTROL-GROUPS

This death certificate-based case-control study linked Connecticut Tum or Registry and Connecticut Division of Vital Statistics death data to determine whether machining fluid exposure is associated with larynge al cancer risk. Laryngeal cancer cases were compared with or-al cancer controls and general population controls. Level of exposure to machin ing fluids was imputed from the usual occupation and industry on the d eath certificate. Because exposure was infrequent among females, analy sis was limited to males. When cases were compared to oral cancer cont rols, high exposure to machining fluids was associated with laryngeal cancer (odds ratio = 1.48; 95% confidence interval = 1.01-2.16), with a p-value for trend of 0.08. When cases were compared to population co ntrols, no association between machining fluid exposure and laryngeal cancer was observed A possible reason for the contrasting results, oth er than chance, is that exposure data quality far the cases and oral c ancer controls may have differed from that of the population controls. (C) 1997 Wiley-Liss, Inc.