Cohort Profile: ChinaHEART (Health Evaluation And risk Reduction through nationwide Teamwork) Cohort

Why was the cohort set up?Non-communicable diseases (NCDs), as the world's largest health threat, cause about 41 million deaths every year, equivalent to 71% of the total deaths. 1 In China, NCDs are also the leading causes of disability-adjusted life-years (DALYs), such as stroke (44.3 million), ischaemic heart disease (30.1 million), chronic obstructive pulmonary disease (COPD) (20.4 million), lung cancer (15.3 million) and diabetes (10 million). 2By controlling risk factors, including tobacco smoking, 3 alcohol use, 4 unhealthy diet, 5 physical inactivity, 6,7 overweight or obesity, 8 abnormal blood lipid levels 9,10 and high blood pressure, 11,12 incidence and mortality of NCDs can be substantially reduced according to robust evidence from previous studies.Therefore, comprehensive knowledge about distribution and influence of risk factors is essential for the development and implementation of targeted prevention strategies.Due to China's large population size and vast territory, there are enormous variations in the prevalence of the aforementioned risk factors across population subgroups and regions. 13,14Moreover, the strength of these risk factors could be of great heterogeneity of which the understanding is still limited.Although several large-scale population-based cohorts focusing on NCDs have been established in the past two decades, 15-17 they are still limited in geographical coverage for reflecting the whole country and in statistical power to detect associations in specific subgroups.Additionally, aetiological studies leveraging biosamples to explore multiomics associations and gene-environment interactions, 18192021 which have increasingly become research hotspots, are particularly sensitive to population size and diversity.Correspondingly, the China National Center for Cardiovascular Diseases (NCCD) has been establishing a nationwide population-based cohort, namely China Health