Changes of Adult Population Health Status in China from 2003 to 2008

Sun, Hongpeng; Zhang, Qiuju; Luo, Xiao; Quan, Hude; Zhang, Feng; Liu, Chang; Liu, Meina

The China National survey employed a multistage cluster sampling to select the sample randomly. The mainland of China was clustered according to the government administrative geographic system [19] . Both surveys were conducted in the same sampling areas, whereas all households were randomly selected again. First, 94 counties and cities were randomly selected from rural and urban areas (95 areas were selected in 2003). Second, 5 towns were selected from each county and 5 communities from each city respectively, resulting in 470 towns or communities. Third, 2 villages in each town and 2 neighborhoods in each community were randomly selected. Fourth, 60 households were randomly selected in each village or neighborhood, resulting in about 56,400 households in 2008 (57,000 households in 2003). During the survey, candidate households that could not be contacted by interviewers on three calls on different days were replaced. Survey completion rate was maintained at .95%. Interviewers, who were trained, explained the purposes and confidentiality of the survey then invited family members to participate. Residents could choose not to participate and their participation in the survey was accepted as oral consent. Adult residents were themselves required to answer questions; if they were not at home at the time of the survey then their nearest relative could serve as proxy. As a result, the survey response rate for adults was 83% in 2008 (77.8% in 2003).