Chemical and histological post-mortem studies on a workman exposed for many years to cadmium oxide fume

Mortality and cancer morbidity among cadmium-exposed workers

Preliminary data are reported from a study of 269 cadmium-nickel battery factory workers and 94 cadmium-copper alloy factory workers. The target group comprises all workers with more than 5 years exposure to cadmium at any time since the factories started production. An internal reference group of 328 alloy factory workers without cadmium exposure was also studied. The expected number of deaths and cancers was calculated with the "life-table" method by using national average incidence rates for men in different age groups and at different calendar years. It was found that among the workers in the battery factory who started work before 1948 there was an increased general mortality in the 1950's mainly due to respiratory disease. The same group had an increased renal disease mortality. There was no increase in general cancer mortality or in general cancer incidence. The risk ratio for nasopharyngeal cancer incidence was 10 (two cases), which was statistically significant. For some other sites like prostate, lung and colon-rectum the risk ratios were also greater than 1 but not statistically significant. In the alloy factory there was a tendency for an increased mortality in prostatic cancer (four cases). After correction for the "healthy worker effect" using the reference group, the risk ratio for prostatic cancer deaths was calculated as 2.4, but this was not statistically significant. The findings in this study support the earlier reports of an association between human cadmium exposure and increased risk for prostatic cancer.

Renal lesions in experimental cadmium poisoning

A series of controlled experiments was carried out on rats to study the effects on the kidneys of the repeated administration of small doses of cadmium for periods of up to 12 months. Renal lesions consisting essentially of tubular atrophy and interstitial fibrosis were produced, and the evidence that these lesions were due solely to cadmium is discussed. No similar lesions occurred in a series of control animals, litter mates of the experimental animals. The lesions were shown to be reproducible in two prolonged experiments on two strains of rats. The relationship between the lesions and the concentration of cadmium in the tissues of the rats is discussed and a comparison is made with tissues from human cases of chronic cadmium poisoning. It is of interest that the cadmium concentration of human tissues and rat experimental tissue is of the same order of magnitude. Animals in which the administration of cadmium was discontinued after five months of the experiment had developed as severe lesions seven months later as those animals which had received cadmium for 12 months. It has been shown previously that the first sign of chronic cadmium poisoning can occur in man for the first time many years after the last exposure, and that the disease once established in man is progressive despite the absence of further exposure.