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The elevated risk of lung cancer among chromate-producing workers has been confirmed by many epidemiological studies. Although chromium has been most used in the chromium plating industry and many platers are employed in small-scale factories, cancer studies have been documented in only a few investigations. We have conducted several prospective cohort studies in Japanese chromium platers and recently extended them through 2003. We additionally surveyed epidemiological studies among chromium platers carried out in other parts of the world. Occupational chromium exposure through chromium plating work may be a risk factor for mortality not only from lung cancer but also malignant lymphoma and brain tumor. The age at first exposure to chromium may be a more important factor than the duration of exposure for an increased risk of lung cancer and malignant lymphoma.

Health hazards due to exposure to chromium in the chromium plating industry has been documented in only a few epidemiological studies. A prospective cohort study was conducted to examine the health hazards of chromium plating with a follow-up period of over sixteen years. Subjects were 1193 male metal platers in the small-scale chromium plating plants in Tokyo. They were divided into a chromium plater subgroup (n = 623) and non-chromium plater subgroup (n = 567) and were followed up from October 1976 through December 1992. The 95% confidence interval (95%CI) of the standardized mortality ratio (SMR) was used to evaluate statistical significance. In the chromium plating subgroup, the risk of chronic hepatitis or liver cirrhosis was significantly elevated (SMR 2.34; 95%CI 1.17-4.19) and a trend toward statistical significance was seen for the risk of lung cancer (SMR 1.18; 95%CI 0.99-3.04). No significantly elevated risk was seen in the non-chromium plating subgroup. We concluded that, as the number of disease-specific deaths was small, further follow-up is necessary.

A survey on sudden unexpected death, that is, death within 24 hours from acute onset, among Japanese workers was carried out. Questionnaires were sent to full-time occupational health physicians who were active members of the Japan Association of Industrial Health at the time of the survey. Though 241 doctors answered (response rate: 61.5%), only 53 of them who had had both sudden death cases and the desire to join in this research co-operated in this survey. During the 5 years of observation (from Jan. 1, 1986 to Dec. 31, 1990), 143 cases of sudden death, 141 males and 2 females, were reported. The mean age was 46.5 (S. D. 10.5) for males. The ages of the 2 females were 31 and 44. Onset took place most frequently at home (55%) and most often during sleep (26%). This may be due to the higher rate not only of onset but of death resulting from acute onset at home and during sleep. Similar to the previous findings, a small peak of incidence was found early in the morning (4:00 AM--9:00 AM), although this was not statistically significant. However, the weekly and seasonal variations were a little different from previous reports. In this study, sudden death tended to occur more on Monday, Thursday, Friday, and Saturday (not statistically significant), and as for the seasonal variation, more cases occurred in April, November, and December which were statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)

We experienced 32 cases of occupational uroepithelial cancer at Jichi Medical School Hospital from 1974 to 1990. All of them were dyestuff workers who had been engaged in production or handling of benzidine, beta-naphthylamine or alpha-naphthylamine. In these 32 cases, upper urinary tract tumors were found in 7 cases, one of these having bilateral lesions. The mean age when the tumor of the urinary tract was first disclosed was 48 years old, with a range of 36 to 66 years old. The mean age of this occupational group was about 16 years younger than that of the spontaneous urinary tract tumor group in our hospital. We divided our cases into two groups according to duration of carcinogen exposure; less than 5 years and 5 years or more. However we did not obtain significant difference in the grade of tumors or prognosis between the two groups. But when we divided them into two groups according to the type of work; production group and handling group, 18 of 21 production workers had high grade tumors. On the other hand, only 3 of 11 handling workers had high grade tumors, which was a significant difference. Besides, 10 of 21 production workers or only one of 11 handling workers were fatal. The difference was also significant. There was no significant correlation among the type of work, the duration of exposure and the age of onset. In our study, we showed that the type of work was quite important to predict the grade of tumors and the prognosis in occupational uroepithelial cancer patients.(ABSTRACT TRUNCATED AT 250 WORDS)

The risk of cancer was analysed in a cohort of 604 male workers who had been engaged in manufacturing and/or handling benzidine and/or beta-naphthylamine during the period 1945-71 at two factories located in the city of Osaka. The cohort was followed up from 1 January 1970 to the date of death or 31 December 1986. The mean follow-up time was 16.1 years. A total of 84 deaths was found compared with 112.66 expected based on the mortality of the Osaka population. Thirty-six were found to be dead of malignant neoplasms; 9 stomach, 2 colon, 1 rectum, 3 liver, 1 bile duct, 1 pancreas, 1 maxillary sinus, 6 lung, 8 bladder, and 2 ureter neoplasms as well as 1 case of myeloid leukemia. Seven cases were ascertained on death certificates as neoplasms of uncertain behaviour, all of which were tumors of genitourinary organs except for one case of brain tumor. Cancers of genitourinary organs and tumors of uncertain behaviour showed statistically significant increased standardized ratios (SMR = 12.20, 4.89). The mean age of death of those having genitourinary organs including cancer was 59 years old, and the latent period between the first exposure and the occurrence of the disease was 19.7 years on average. Non-significant increased risks of cancers of the colon, rectum, liver and lung were observed among the workers exposed to benzidine. Among the 7 histologically confirmed cases of these cancers, there were 2 adenocarcinomas of the lung, 1 adenocarcinoma of the rectum, 2 hepatocellular carcinoma and 1 adenocarcinoma of the bile duct. Seven patients with genitourinary tumors were found to have died of other primary cancers.

This report describes a cohort study conducted on workers who were employed in a factory mainly manufacturing asbestos yarn and cloth and were followed from 1964 to 1981. A total of 208 workers (73 males and 135 females) could be traced and 15 deaths were observed by the end of 1983. Among them, three had lung cancer and its relative risk was 6.8 (p less than 0.05) computed based on the age, sex and year specific death rates of Osaka Prefecture. One case of peritoneal mesothelioma was also found. The period from first asbestos exposure to death of these four cases of asbestos-related malignancies was more than 25 yr. In the analysis of the employees who had more than 1 yr of exposure to asbestos and those who had already been engaged in this factory at the beginning of the observation, the relative risk of lung cancer was 8.1 and 13.6, respectively.

In 1971 and 1973, Yoshida, et al. reported a higher relative risk of urinary bladder cancer among the workers of dyeing factories in Kyoto city. In order to confirm this, death certificates in Kyoto city from 1969 to 1972 were retrospectively investigated. Kyoto city was devided into three areas, that is, areas with high, medium and low clusterings of dyeing factories, and the differences of the mortality rates of all causes of deaths among these three areas were examined. As a result of this study, a statistically significant difference of the mortality rate of bladder cancer could not be found for males. But, the relative risk of bladder cancer in the areas with high and medium clusterings of dyeing factories compared to the area with low was found to be 1.45. Therefore, the relationship between dyeing work and bladder cancer could not necessarily be denied. It is, thus, necessary to carry out a prospective study, by which a more precise result can be obtained. In addition, our study revealed a significantly high mortality rate of skin cancer among the areas with high and medium clusterings of dyeing factories for males, observing a relative risk of 3.88. The observed association between skin cancer and dyeing work should be further studied.

In order to clarify the long-term effect of tunnel work on the health of its workers, we examined its cause-specific mortality pattern. The subjects were 418 males who died after the age of 30 in 1977 in the southern part of Oita Prefecture, where many men come and work away from home as tunnel workers. Death certificates, 418 in number, presented to the health center were used to examine the causes of death. Occupational careers and life histories of the subjects were obtained by interviewing their families or relatives in 1980. The interviews were successfully carried out with 356 subjects (85.2%). The subjects were divided into two groups. One group was consisted of 73 males who had engaged in the tunnel work (tunnel workers) and the other was of 283 males without experience of tunnel work (others). Proportional mortality ratio (PMR) and proportional mortality classified by age were compared between the two groups. The mean ages at death were also compared among these two groups and all Japanese males over 30 years of age. The results were as follows. The proportion of the deaths of "tunnel workers" among the total deaths in the area surveyed was correlated to the regional rate of tunnel workers and the distribution of pneumoconiosis due to tunnel work. These results show that many tunnel workers suffering from pneumoconiosis had returned to their home area before they died. Excess deaths from the ICD category I; infective and parasitic diseases (000-136), tuberculosis (010-019) and silicotuberculosis (010) were found among the "tunnel workers."(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical and statistical observations were made on a group of 438 persons who had worked with aromatic amines (benzidine, 2-naphthylamine, 1-naphthylamine and dianisidine) with reference to their carcinogenic properties in the urinary tract. Urinary tract tumors developed in 68 (15.5%), with an average latent period of 22 years and 11 months. In these 68 cases, upper urinary tract tumors were found in 16 cases, 8 of which had bilateral lesions. The average age of onset was 48.1 ranging from 24 to 79. The incidence of tumors increased with the length of exposure to the amines. There was no finding that smoking habit increased the incidence of tumors in this group. Of the 49 new patients with bladder tumor, urine cytology was positive in 24 (49.0%) and suspicious of malignancy in 10 (20.4%), respectively. This indicated that it could be a useful screening test. Transurethral surgery was most frequently performed as an initial treatment. Recurrence occurred in 50 cases (73.5%), but 5-, 10- and 20-year-survival rates were 89.0 79.3 and 64.7%, respectively, showing a good prognosis. Malignant tumors in other organs developed in 18 (4.1%) of the 438 workers. The incidence of such malignant tumors was significantly higher in the workers who had been exposed to 2-naphthylamine than in others. Our data indicate that close observation is still necessary for early detection of patient with new or recurrent urothelial carcinoma in this group.

A total of 90 dyestuff workers who were engaged in the production of aromatic amines during the post-war period after the 2nd world war have been examined since 1967 by exfoliative cytologic examination. Those identified as class-3 or over by this first screening test were then submitted to a second screening which consisted of periodic cystoscopic examination and 1 or 2 intravenous pyelographies per year. This system of mass screening has been used for the past 20 years, and we have discovered 23 cases of bladder tumor, a case of asynchronous bilateral ureteral tumor and a case of ureteral tumor. Out of the 13 cases, bladder tumors were discovered in 6 cases within 3 months after a positive exfoliative cytology result and in 5 cases within 1 year. The presence of a tumor was confirmed in 85% of those patients within 1 year and in all of them in about 3 years. Periodic examinations have revealed all the tumors when they were about 5 mm in size and in stage 0 through A, demonstrating the usefulness of systematic examination. Treatment included intravesical instillation of anticancer agents, mostly mitomycin C, for 7 cases transurethral resection (TUR) for 8 cases and partial cystectomy was performed in one case. One patient with an asynchronous bilateral ureteral tumor was treated first by right total nephro-ureterectomy with cuff resection of bladder, and later by ureter excision and nephrostomy. This patient died of ileus in the 7th year of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Tunnel work, digging a tunnel at the face, is a highly specialized job today. Many tunnel workers migrate from one place to another away from home throughout the year. They are exposed to hazardous factors such as dust, vibration, noise and so on, working under the two 12-hour shift system. Recently it has been reported that many workers who had suffered from pneumoconiosis and/or vibration disease returned to their home areas. The southern part of Oita Prefecture is well known as being one of the areas which supply many tunnel workers. In order to study the long-term effects of tunnel work on the health of the tunnel workers, the authors compared the mortality rate in the district supplying many tunnel workers with that of the district supplying few workers. Nine causes of death were chosen among many as indices indicating the characteristics of the structure of mortality in the district supplying many tunnel workers. The authors estimated these causes of death in relation to sex and age, analyzing simple correlations between the 9 causes of death and 33 socioeconomic factors. A principal component analysis of these indices was also carried out. The results were as follows. A close relationship was found between tunnel work and three causes of death such as silicotuberculosis (010), tuberculosis (010-019, A 6), and infective and parasitic diseases (000-136). The other 5 causes of death such as diseases of the digestive system (520-577), neoplasms (014-259), all causes (000-999), stomach cancer (151, A 47) and pneumoconiosis (515) were related not only to tunnel work but also to other regional characteristics such as fishery workers rate. No relationship was found between tunnel work and death by cerebrovascular disease (430-438, A 85). These results show that the tunnel work has an influence on the structure of mortality in the area supplying these workers.