AbstractBackgroundData on dementia mortality are routinely collected by governments and used in health research. However, historical underrecording of dementia on death certificates has limited the utility of this widely available data source. Considerable effort has been invested in raising awareness of dementia, increasing diagnosis rates, and improving dementia recording on death certificates. Updated versions of the ICD‐10 rules for coding the underlying cause of death, implemented in Scotland in 2011 and 2017, have increasingly assigned deaths that mention both dementia and respiratory or urinary tract infections towards an underlying cause of dementia, if no other underlying medical condition is mentioned. Since previous cohort studies have shown geographical variation in dementia risk, this study utilises spatiotemporal modelling to investigate changes in dementia‐associated deaths in Scotland.MethodData on dementia and Alzheimer’s deaths and mid‐year population estimates available from the National Records of Scotland for the time period 2000‐2019 were used to build a Bayesian spatiotemporal disease mapping model. The data were grouped by the 32 Council areas and year, whilst stratification by age and gender were built into the model. The analyses were run in R using Integrated Nested Laplace Approximation methodology.ResultThe data show strong temporal and spatial trends in the relative risk of dementia‐associated death. The relative risk increases progressively over the time period studied, with a 2.3‐fold increase (95% Confidence Interval: 2.1‐2.5) between 2000 and 2019, reaching levels just below predicted dementia prevalence in recent years. The relative risk varies geographically and is highest in Scotland’s industrialised central belt region and lowest in the rural areas and islands, with a relative risk of 1.9 (95% CI: 1.6‐2.3) between the lowest and highest risk Council areas.ConclusionThere are factors, other than the step changes in underlying cause of death coding, driving the progressively increasing temporal trend in relative risk of dementia‐associated death. These factors could be a combination of increased dementia awareness, a larger proportion of people being diagnosed, greater recording on death certificates and, possibly, increasing prevalence. The strong spatial variation in relative risk in Scotland indicates that there are geographically‐varying factors affecting this risk.