In August, an exciting new research study was published that drew on the results from five population studies from four European countries—the UK, the Netherlands, Spain and Sweden, which had two population studies sampled. The results have significance for governments and dementia researchers across the globe, but also here in Canada.

One of the most important findings was that all five studies examined showed remarkable similarities in dementia prevalence (total number of cases per population) by age, sex and years of observation. Dementia prevalence rate also consistently doubled every 5 years in each age group greater than 65.

Another interesting result, which has been observed in other studies as well, was that prevalence rates decreased slightly through time, but this was observed among men rather than women, for which the dementia prevalence rate did not change. The population study in Spain showed significant reductions among male prevalence rates and the studies done in Stockholm and Rotterdam also showed a similar trend.

Canada has a lot in common with these countries and the results are relevant to us. The slight decrease in dementia prevalence suggests that each generation of elderly people will have had different positive and negative effects on their health during their lives. Established risk (e.g. vascular diseases) and protective (e.g. education) factors for dementia have changed hugely during successive generations.

Because of these changes in life expectancy and risk profiles, we would expect to see emerging variation in occurrence of dementia over time and between different countries. However, the lack of variation between countries makes such a conclusion unsupported at this time. It is possible that increased awareness of dementia is leading to more mild cases being diagnosed, which would counter the effect of reduction occurring in Europe. More research is needed but the results are interesting.

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Dr. Larry Chambers

Scientific Advisor, the Alzheimer Society of Canada