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The China Kadoorie Biobank’s third resurvey of 25,080 participants from all ten study regions is now complete.

After some delays due to the COVID-19 pandemic, fieldwork of the third resurvey has been conducted between August 2020 and December 2021 and a range of new measurements have been collected. Objectively-measured physical activity and sleep data was collected via a wrist-worn accelerometer in 21,400 participants; saliva and faecal samples were collected from 24,788 and 19,926 participants respectively providing exciting opportunities for future human microbiome-related studies; eye measurements (including visual acuity, intraocular pressure and retinal images) were collected in over 24,820 participants; liver scans (to detect liver steatosis and liver fibrosis) were performed among 24,275 participants. 

The questionnaire used for this resurvey was greatly updated with details in areas such as gut health, vision, hearing, frailty, urinary incontinence and e-cigarette use. Copies of the resurvey and baseline questionnaires can be found in the study resources section of the website.

The collection of new measurements required substantial work from the CKB IT team, which included updating existing programs for device data collection (eg, body composition, BP, ECG, lung function, carotid artery ultrasound), and developing software to facilitate new data and sample collection (e.g. liver scan data, retinal images and saliva and stool samples).  Secure WIFI networks were also established in the survey clinics to allow automatic data sharing between different stations.  Overall,  approximately 20 new IT systems were developed, with another ~40 systems substantially upgraded and improved.

Colleagues from Peking University and Oxford University will work closely together to clean the data and process the raw information (retinal images and accelerometer signals) before it is made available to researchers through the CKB Data Access System.