Assessing the joint prevalence of dementia and hearing loss in Scotland: a growth model for public health planning

Abstract

Abstract Aim Data in Public Health studies often comes in mismatched age groups. This study investigated how mathematical modelling techniques could be used to estimate the number of individuals with dementia and hearing loss in Scotland given heterogeneous age group data. Subject and Methods Using established criteria for modelling hearing loss, current population level estimates from the Scottish National Records office were employed to calculate general estimates of the number of individuals with hearing loss in Scotland. Additionally, age group models developed by the European Collaboration on Dementia were used to generate estimates of the number of people with dementia in Scotland. To estimate the number of individuals with both conditions, the two models were combined in a single formula. Parameter optimization was performed on various growth models to determine the best fit to the data. Results The Stannard growth model was found to be the best fit to the data. Conclusion The prevalence of hearing loss, dementia and their co-occurrence exhibit a sigmoidal pattern, which is well-captured by the Stannard growth model, a logistic, sigmoidal type model. This study demonstrates the potential of mathematical modelling to provide nuanced and robust estimates of the prevalence of hearing loss, dementia and their co-occurrence given heterogeneous data sources. A lookup table is provided.