Sample

In 1989, the China Health and Nutrition Survey (CHNS) surveyed 3,795 households and 15,907 individuals. Health and nutritional data were collected only from preschoolers and adults age 20 to 45. The 1991 CHNS surveyed only individuals belonging to the original sample households, which resulted in a total of 3,619 households and 14,778 individuals. Since 1993, all new households formed from sample households who resided in sample areas were added to this sample. Since the CHNS 1997, all newly formed households who resided in sample areas and additional households to replace those no longer participating were added to the sample. New communities were also added to replace communities no longer participating, and Heilongjiang province was added. Since the CHNS 2011, three megacities (Beijing, Chongqing, and Shanghai) were added. Since the CHNS 2015, three new provinces (Shaanxi, Yunnan, and Zhejiang) were added and fully supported by our Chinese collaborator, China Center for Disease Control and Prevention.