Excess Relative Risk of Solid Cancer Mortality after Prolonged Exposure to Naturally Occurring High Background Radiation in Yangjiang, China

1 Laboratory of Industrial Hygiene, Ministry of Health, No. 2 Xinkang Street, Deshengmenwai, Beijing 100088, China 2 Department of Public Health, Kagoshima University Faculty of Medicine, Sakuragaoka 8–35–1, Kagoshima 890–8520, Japan 3 Labor Hygiene Institute of Hunan Province, 5 Yu Hua Road, Changsha 410007, China 4 Guangdong Institute of Prevention and Treatment of Occupational Diseases, 165 Xingangxi Road, Guangzhou 510310, China 5 Atomic Energy Research Institute, Kinki University, 3–4–1 Kowakae, Higashi-Osaka 577–8502, Japan 6 Radiation Effects Research Foundation, 5–2 Hijiyama-park, Minami-ku, Hiroshima 732–0815, Japan 7 Health Research Foundation, Pasteur Building 5F, 103–5 Tanaka-monzen-cho, Sakyo-ku, Kyoto 606–8225, Japan