| Co-Investigator(Kenkyū-buntansha) |
LAGARDE F. Radiation Effects Research Foundation, Department of Statistics, research scientist, 統計部, 研究員
F Lagarde 放射線影響研究所, 統計部, 研究員
山田 美智子 放射線影響研究所, 臨床研究部, 副部長 (90359456)
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| Budget Amount *help |
¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 2006: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2005: ¥1,100,000 (Direct Cost: ¥1,100,000)
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| Research Abstract |
Lifestyle factors such as tobacco, alcohol, and low intake of fruit and vegetables are thought to increase the risk of cancer incidence and mortality. Ionizing radiation exposure is a well-known factor of cancer risk. We investigated the combined effect of lifestyle factors and radiation against the long-term effects of radiation exposure on the risk of oesophageal cancer. A cohort of 38,430 atomic-bomb survivors of Hiroshima and Nagasaki, for whom radiation dose estimates based on the dosimetry system DS02 were currently available, had their lifestyle such as tobacco, alcohol, and diet assessed by mail survey in 1980. Incident cases of oesophageal cancer were identified through linkage with the cancer registries in Hiroshima and Nagasaki.
During a follow-up of 20 years (507,549 person-years), 110 oesophageal incidence cancer cases were identified. The incidence rate was 22 oesophageal cancers per 100,000 population.
Tobacco smoking, alcohol drinking, low intake of green and yellow vegetables, intake of food and drinks at hot temperature were strong determinants of oesophageal cancer, with a significant dose-response relationship. Ionising radiation exposure increased the risk of oesophageal cancer, although no significant dose-response relationship was observed. The combined effect of tobacco and alcohol had a synergistic effect on the risk of oesophageal cancer. Regarding the combined effect of lifestyle factors and radiation, the observed risks were greater than the expected risks in the additive model, as well as in the multiplicative model. However, there was no significant evidence to reject either the additive or the multiplicative model, showing an absence of interaction.
We were not able to show a synergistic effect between unhealthy lifestyles (tobacco smoking, alcohol drinking, inappropriate diet) and radiation exposure on the risk of oesophageal cancer among a cohort of atomic bomb survivors.
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