Hiraoka T, Ando M, Shima K, Kinuwaki E, Kiyota S, Futatsuka M, Fujita M
National Kumamoto Minami Hospital, Japan.
Nihon Kyobu Shikkan Gakkai Zasshi. 1996 Apr;34(4):385-91.
A high prevalence of pleural plaques (41.5%, 148/357) was found during a mass screening for lung cancer in Matsubase town in 1988. The inhabitants of this town were carefully studied each year from 1988 to 1993. The vast majority (81.2%) of inhabitants over the age of 20 years underwent chest roentgenography at least once during this period. Pleural plaques were detected by CT in 938 subjects, which is 17.3% of those studied and 4.1% of the total population. A total of 89 had an occupational history of asbestos exposure, 64 (71.9%) of whom had pleural plaques. However, these subjects with occupational exposure accounted for only 6.8% of the 938 subjects, and therefore most of the pleural plaques seemed to have been caused by general environmental exposure. The incidence of plaques was greater in older subjects: among those in the seventh decade of life it was more than eight times higher than among those in the fourth decade of life. Anthophyllite was detected in the main asbestos mill. The concentrations of asbestos fibers in the air and water near the old asbestos mills and factories were not high. The death rates and the adjusted mortality rates due to lung cancer in Matsubase were lower than in surrounding towns and lower than in Kumamoto prefecture as a whole. These results indicate that there is now no environmental contamination by asbestos fibers in Matsubase town. No cases of malignant mesothelioma have been confirmed in this town during the past 17 years.
1988年在松前町进行肺癌大规模筛查时发现胸膜斑的患病率很高（41.5%，148/357）。从1988年到1993年每年都对该镇居民进行仔细研究。在此期间，20岁以上的绝大多数居民（81.2%）至少接受过一次胸部X线检查。通过CT在938名受试者中检测到胸膜斑，占研究对象的17.3%，占总人口的4.1%。共有89人有石棉接触职业史，其中64人（71.9%）有胸膜斑。然而，这些有职业接触的受试者仅占938名受试者的6.8%，因此大多数胸膜斑似乎是由一般环境接触引起的。胸膜斑的发病率在老年受试者中更高：在70岁年龄段的人群中，其发病率比40岁年龄段的人群高出八倍多。在主要的石棉厂检测到直闪石。旧石棉厂和工厂附近空气和水中的石棉纤维浓度并不高。松前町的肺癌死亡率和调整后的死亡率低于周边城镇，也低于整个熊本县。这些结果表明，松前町目前不存在石棉纤维对环境的污染。在过去17年中，该镇未确诊恶性间皮瘤病例。
