The study population is drawn from the nine provinces of Guangxi, Guizhou, Heilongjiang, Henan, Hubei, Hunan, Jiangsu, Liaoning, and Shandong.
China | People's Republic of China | World Health Organization | National Institutes of Health | United States Geological Survey | Communist Party of China | National Health Service | Ordnance Survey | United States Department of Health and Human Services | South China Sea | History of China | Harvard School of Public Health | Great Wall of China | Coast Survey | China Central Television | United States Public Health Service | Health | East China Sea | British Geological Survey | South China Morning Post | South China | public health | Occupational Safety and Health Administration | China proper | Secretary of State for Health | South China AA | Sloan Digital Sky Survey | Discovery Health Channel | Renmin University of China | Bank of China |