方法采用横断面研究。资料来源于中国卫生部统计信息中心1998年第2次国家卫生服务调查数据库。
Methods Cross-sectional analysis of data about smoking behavior and socioeconomic status ( education , occupation and neighborhood income ) are performed using data from the Second National Health Service Study ( 1998 ) of China Ministry of Health .
卫生部统计信息中心