Deirdre Hennessy - Modelling dementia in populations: An important task with challenges

  • Presenting author: Deirdre Hennessy (Statistics Canada)

  • Authors: Deirdre Hennessy, Noah Bolohan, Joel Barnes , Stacey Fisher, Carol Bennett2, Claude Nadeau, Victoria Silverman, Ahmed Al-Jaishi, Rj Edjoc, Rochelle Garner and Doug Manuel

  • Session: C04A - Health [4] - Wednesday 16:00-17:00 - Ceremonial Hall


Dementia, defined as Alzheimer’s and related dementias, has a significant and growing impact on Canadians. According to the latest national data, almost 474,000 people aged 65 and older have been diagnosed with dementia in Canada with that number expected to rise as the population ages. Moreover, dementia places a heavy burden on caregivers and health care systems, and projecting its likely incidence and prevalence is useful as an aid to policy-makers in planning for social, health, and health human resources.


The objective of this collaboration with the Public Health Agency of Canada (PHAC) was to support the Canadian National Dementia Strategy. To achieve this, we developed a microsimulation tool that enables policy makers to investigate the future burden of dementia in Canada, as well as the contribution of modifiable risk factors to dementia incidence.


The objective was achieved by integrating a published and validated statistical model, the Dementia Population Risk Tool (DemPoRT), into an existing microsimulation model of chronic disease, the Population Health Model (POHEM). Specifically, a dementia state was added to the POHEM starting population and was updated over time using a simplified version of the sex-specific DemPoRT algorithm, including variables for age, education, ethnicity, body-mass index, physical activity, smoking, alcohol intake, hypertension, diabetes, heart-disease, and stroke. Modelled dementia incidence was calibrated to the Canadian Chronic Disease Surveillance System (CCDSS) outputs by year, age group and sex.


DemPoRT was successfully integrated into POHEM, and the resulting microsimulation tool was called POHEM-Dementia. Overall crude dementia incidence counts are projected to increase in Canada through 2035 for both males and females over the age of 65. Dementia incidence counts across important risk factors will be presented and discussed, as well as the challenges involved in modelling dementia, including defining dementia, using appropriate variables, modelling outcomes among the very elderly and model calibration.