Consolidation of the AgeX database (2021-24)

In 2021, screening was completed of all participants (including those delayed by COVID). Data linkage had been disrupted by the pandemic and by the replacement in 2021 of Public Health England by NHS England. By 2024, however, data linkage to all relevant NHS records had been re-established and the whole database had been consolidated, defining the pre-randomisation characteristics only from sources that could not have been affected by the random allocation.

Data linkage

During randomisation, the National Breast Screening System (NBSS) and, later, Breast Screening Select (BSS) provided information on new AgeX participants. Identifiers such as name, NHS number and date of birth were included for secure (Annex 2) onward linkage to several other sources:

• NHS screening records (for information about screening history);
• Death and cancer registry data, including the Cancer Outcomes and Services Dataset (for information on cause-specific mortality and details of incident cancers, including tumour histology, size, stage, grade, nodal involvement and receptor status);·        
• NHS Hospital Episode Statistics (for information on cause-specific hospital admissions and procedures, including systemic breast cancer treatments, particularly chemotherapy, and surgery, particularly mastectomy);
• The Systemic Anti-Cancer Therapy data set (for information on chemotherapy)
• The Radiotherapy Dataset (for information on radiotherapy); and  
• Data approved for anonymous transfer from the nationwide prospective Million Women Study (for information on quality of life).

Such routine records, all but the last of which are currently being provided to AgeX by NHS England, will cease if women decide to opt out of having their further NHS records used for research or emigrate.