Asbestos and cancer in the Sennan District of Osaka

Our plain-English summary of Asbestos and cancer in the Sennan District of Osaka, by Y. Sera, K.Y. Kang (The Tohoku Journal of Experimental Medicine, 1981).

The study

• Authors: Y. Sera, K.Y. Kang
• Journal: The Tohoku Journal of Experimental Medicine
• Published: 1981;133(3):313-20
• Cited by: 4 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

The cancer incidence among asbestos workers in the Sennan District and its surrounding of Osaka Prefecture, Japan, and the results of a mass survey in the above area since 1957 were evaluated from view points of epidemiology. During the period from 1953 to 1979, 107 patients with asbestosis were admitted to this Hospital. Twenty-six (24%) of them died of various carcinoma; 21 had lung cancer, 2 pleural mesothelioma and 3 had stomach cancer. Respiratory insufficiency due to pulmonary asbestosis was responsible for 41 deaths (38%). by a cohort survey of the 297 asbestos workers in the same district, 4 cases of lung cancer, and 3 cases of gastric cancer were detected and cases of cohort survey were followed up for 19 years. Fifty-seven (10%) of 556 cases of silicosis and 14 (11%) of 125 cases of pneumoconiosis other than silicosis or asbestosis were found to have lung cancer, but no mesothelioma. These results indicate that lung cancer and mesothelioma are associated more frequently with asbestosis than with non-asbestos pneumoconiosis (p less than 0.001 as tested by chi2-test). The standardized mortality ratio of lung and stomach cancer among the inhabitants of the Sennan District was calculated based on the statistics during the period of 10 years (1968-1977). the ratio of observed death to expected death of both cancers was smaller than 1.1, and there was no significant increase of death of lung and stomach cancer, although the risk of lung cancer tended to increase among male inhabitants. Discussions were made on the problems related to asbestos industry.

In plain English

The authors, at a chest hospital in Sakai, Japan, studied cancer among Sennan District asbestos workers in Osaka. Small factories made asbestos textiles for joint-sheet and brake-lining, now mostly from chrysotile, formerly also using small quantities of amosite. Of 107 patients with asbestosis admitted from 1953 to 1979, 26 (24%) died of cancer: 21 of lung cancer, 2 of pleural mesothelioma and 3 of stomach cancer. Another 41 (38%) died of respiratory insufficiency due to asbestosis. Lung cancer or mesothelioma occurred in 23 (22%) of the 107. By comparison, lung cancer occurred in 57 (10%) of 556 silicosis patients and in 14 of 125 patients with other pneumoconioses (p less than 0.001). Of workers first surveyed in 1957, only 297 of 818 could be followed; among them, 4 lung cancers and 3 gastric cancers were found. Among residents from 1968 to 1977, lung and stomach cancer deaths were not significantly raised, though male lung cancer deaths tended to rise slightly, which the authors said needed long-term surveillance. From these patients' deaths, the authors suggested severe asbestos exposure causes more deaths than malignancies.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Hospital case series of asbestosis patients compared with other pneumoconiosis patients, plus a follow-up of a 1957 cohort of asbestos workers and a standardized mortality ratio (observed versus expected deaths) analysis of local residents
• Who was studied: 107 patients with asbestosis admitted to the National Kinki-Chuo Hospital for Chest Disease from 1953 to 1979, compared with 556 silicosis patients and 125 patients with other pneumoconioses; asbestos workers in the Sennan District first surveyed in 1957, of whom 297 of 818 could be followed; residents of Sennan City (population 50,000) and Hannan Town (38,000), 1968 to 1977
• Exposure: Work in small Sennan District asbestos factories producing mostly textiles for joint-sheet and brake-lining. These factories formerly used a small quantity of amosite; most raw material now used is chrysotile imported from Quebec, Canada
• Main results:
  • Of the 107 asbestosis patients, 26 (24%) died of various carcinomas: 21 had lung cancer, 2 pleural mesothelioma and 3 stomach cancer
  • Respiratory insufficiency due to pulmonary asbestosis caused 41 deaths (38%) among the 107 asbestosis patients
  • Among the 19 patients diagnosed with lung cancer (17) or mesothelioma (2), duration of asbestos exposure ranged from 1 to 42 years
  • 17 of these 19 patients were cigarette smokers
  • Histology of the 19 cases showed 5 adenocarcinomas, 5 squamous cell carcinomas, 4 large cell carcinomas and 3 mixed-type carcinomas; the 2 pleural mesotheliomas were diagnosed at autopsy
  • The first survey of Sennan District workers in 1957 detected 88 cases (11%) of asbestosis; by 1976, 40 of the 88 were dead
  • 297 (37%) of 818 workers of the 1957 cohort could be followed up; records of the remaining 517 were unavailable
  • In the cohort survey of the 297 asbestos workers who could be followed, 4 cases of lung cancer and 3 cases of gastric cancer were detected
  • Lung cancer or mesothelioma was found in 23 (22%) of the 107 asbestosis patients. Lung cancer was found in 57 (10%) of 556 silicosis patients and in 14 of 125 patients with other pneumoconioses
  • Lung cancer and mesothelioma were more frequently associated with asbestosis than with silicosis (p less than 0.001) or non-asbestos pneumoconiosis (p less than 0.001)
  • Among male residents of Sennan City, 1968 to 1977, observed lung cancer deaths were 37 against 35.1 expected (observed/expected 1.1). The ratio was 1.1 for females in Sennan City, 1.1 for males in Hannan Town and 1.0 for females in Hannan Town
  • The authors described the risk of lung cancer in male residents as showing a tendency toward a slight increase that was not statistically significant, and said this indicated the necessity of long-term surveillance on cancer in the district
  • Observed/expected ratios for stomach cancer deaths among residents were 1.0 (males) and 1.0 (females) in Sennan City, and 1.1 (males) and 0.9 (females) in Hannan Town; there was no significant increase
  • Of 51 cases of asbestosis identified in 1957, 2 (4%) were found to have lung cancer after 15 years of follow-up
• The authors' conclusion: From the deaths among their asbestosis patients (41 from asbestosis versus 26 from malignancies), the authors suggested that severe asbestos exposure causes more deaths than malignancies. They considered it very likely that heavily exposed Sennan District patients die of asbestosis before cancer develops
• Limitations the authors state:
  • The cohort survey does not cover all workers employed in the Sennan District factories
  • Records of 517 workers in the 1957 cohort were unavailable
  • No extensive survey of gastrointestinal tumors was carried out
  • Figures for graphitosis and aluminum lung may not be significant because of the limited number of cases
  • Stomach cancer cases may be under-detected: patients with gastrointestinal complaints generally do not visit chest clinics, and factory managers are reluctant to let employees visit the hospital

Topics

Medical terms in this study, explained in our Lexicon: Epidemiology, Carcinoma, Lung Cancer, Pleural Mesothelioma, Stomach Cancer, Asbestosis, Silicosis, Pneumoconiosis.

Related studies

• Cancer incidence in urban, rural, and densely populated districts close to core cities in Bavaria, Germany — M. Radespiel-Tröger, K. Geiss, et al. (2018)
• Excess mortality from stomach cancer, lung cancer, and asbestosis and/or mesothelioma in crocidolite mining districts in South Africa — J.L. Botha, L.M. Irwig, et al. (1986)
• Re: "Excess mortality from stomach cancer, lung cancer, and asbestosis and/or mesothelioma in crocidolite mining districts in South Africa" — H.P. Hart (1987)
• Updated mortality study of a cohort of asbestos textile workers — E. Pira, C. Romano, et al. (2016)
• Mesothelioma incidence in 50 states and the District of Columbia, United States, 2003-2008 — S.J. Henley, T.C. Larson, et al. (2013)
• Prevalence of pleural calcification in persons exposed to asbestos dust, and in the general population in the same district — M. Navrátil, F. Trippé (1972)

Browse return to medical research.