Demographic change, death certification and recorded mortality from central nervous system tumours in Europe: study protocol for a decomposition of change since 2003 and projections to 2040

Study protocol (version 1.0) for a secondary analysis of published, aggregate vital-registration data from the WHO Mortality Database and Eurostat for 31 European countries and the United Kingdom. The study partitions the change in recorded deaths from central nervous system tumours between 2003–2005 and 2020–2022 into the contributions of population size, age-sex structure, changes in the coding of deaths between malignant (ICD-10 C70–C72) and benign or uncertain-behaviour codes (D32–D33, D42–D43), and residual change in age-specific mortality. Deaths are projected to 2040 with models selected by out-of-sample evaluation against a constant-rate benchmark. The protocol was deposited before the primary analysis was run. Section 7 describes the feasibility pilot carried out beforehand and the design changes made in response. Deviations from the protocol will be reported in the publication.