1980 Volume 71 Issue 8 Pages 945-951
The production of benzidine and β-naphthylamine in Wakayama was started in the early 1920's and continued until Sep. 1972 when the synthesis and handling of these materials were prohibited by law. According to the records of the Wakayama Labor Standard Office, at least 1, 085 workers were exposed mainly to benzidine during this period. Of the 1, 085 workers, 56(5.2%) have been confirmed to have had the urinary tract tumor by this time.
The average age when the tumor of the urinary tract was first disclosed was 53.2±11.3 yrs. (Mean± S.D.) for this occupational group and 64.0±11.5 yrs. for the patients (340pts.) with spontaneous urinary tract tumor. The difference was significant (p<0.001).
The latent period was estimated as 19.9±9.7 yrs. in total, but the older the age of workers at the start of exposure, the shorter their latent period. Especially, the patients who had begun the exposure over 50 revealed a significant reduction of the latent period (9.2±3.1 yrs.)
There was no significant difference in the survival rate between the occupational group and the spontaneous group. The proportions of renal pelvic, ureteral and bladder tumor to each group were also shown to be insignificant.
