2001 Fiscal Year Final Research Report Summary
Epidemiological studies on environmental determinants (excepting smoking) of lung cancer, especially adenocarcinoma
| Project/Area Number |
12670316
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Hygiene
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| Research Institution | Niigata University |
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Principal Investigator |
NAKADAIRA Hiroto Graduate School of Medical and Dental Sciences, Department of Community Preventive Medicine, Niigata University, Lecturer, 大学院・医歯学総合研究科, 講師 (40217758)
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| Co-Investigator(Kenkyū-buntansha) |
YAMAMOTO Masaharu Graduate School of Medical and Dental Sciences, Department of Community Preventive Medicine, Niigata University, Professor, 大学院・医歯学総合研究科, 教授 (40018693)
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| Project Period (FY) |
2000 – 2001
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| Keywords | Lung cancer / Adenocarcinoma / Standardized incidence ratios / Standardized mortality ratios / Heavy metals / Arsenic / Lead / dioxins |
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| Research Abstract |
We conducted the mortality and incidence analyzes of lung cancer and investigated the environmental pollution levels of heavy metals and dioxins as potential determinants of geographical clustering of lung cancer in Niigata Prefecture, Japan.
The standardized mortality ratios of Lung cancer did not show any geographical variation. On the other hand, the standardized incidence ratios (SIRs) differed significantly from area to area. It was still remarkable when lung cancer incidence was analyzed by type of histology. The SIR of adenocarcinoma was high in the districts along the Agano for both genders. The SIR of squamous cell carcinoma showed geographical variations for men only. However, the variation of the rate of histological verification should be considered a possible confounding factor.
We then measured the concentration of heavy metals that were reported to be related to lung cancer in soil samples collected from two lagoons in Niigata city. We identified the specific year of each
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soil samples by Pb 210 and Cesium 137 methods. Among metals investigated, As had a peak of concentration in 1970s (80〜100ppm). Pb increased year by year and the peak of concentration was in 1980s. The transition of the concentration of dioxins, which are known as promoters in cancer etiology, was more characteristic. The TEFs of PCDD/DFs were 14.4〜297.4pg-TEQ/g (mean = 99.5pg-TEQ/g) in one lagoon, 6.6〜45.5pg-TEQ/g (mean=28.7pg-TEQ/g) in another. The values were higher than the national average. The peak plateau was found between 1970 and 1980. The main origin of dioxin pollution was agricultural chemicals, especially CNP and PCP, which accounted for more than half of the TEFs of dioxins. We concluded that the pollution by dioxins was the severest a couple of decades ago.
In the present study, it was not possible to investigate the relation between the pollution by heavy metals or dioxins and the geographical clustering of lung cancer due to the paucity of sampling sites. The next step we should take is to increase sampling points and to measure human tissue samples by histology of lung cancer. Less
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