[Principles and practice on cohort study of general population in Beijing, Tianjin and Hebei province].

Cohort study has emerged as an essential tool for gaining knowledge about risk factors and prevention of diseases. The studies related to cohort population have been progressing more than 60 years in our country, while different types and numbers in cohort studies have increased dramatically with the key programs special for the cohort study were approved firstly by the Ministry of Science and Technology of China since 2016. With typical study design, cohort study is currently needed to use the latest multidisciplinary resources and methods in order to be more systematic and accurate on association analysis and causal inference of diseases. For the cohort study of general population in Beijing, Tianjin and Hebei province, the core principles and concepts of study design, progress and the key issues targeting implementation were introduced. In addition, opportunities, bottlenecks and solutions facing us were also explored.