Authors: Alice Weatherston
Contrary to recent worries over the ‘dementia epidemic’, a new epidemiological analysis by experts in the field has indicated that the number of individuals with dementia may in fact be stabilizing in some Western European countries. The study, which was published in The Lancet Neurology, suggests that both new cases and the total numbers of individuals with dementia may have fallen over the last 20 to 30 years.
The investigation looked at data collected in five large epidemiological studies carried out in Sweden, the Netherlands, the UK and Spain, which all compared dementia occurrence in the elderly across two different time periods.
Carol Brayne (University of Cambridge, UK), lead author of the study, discussed the need for newer research on the number of dementia cases in order to efficiently inform care provision planning in countries: “…old studies support the idea of a continuing ‘dementia epidemic’, but are now out of date because of changes in life expectancy, living conditions, and improvements in health care and lifestyle.”
In four of the five studies non-significant changes in overall dementia occurrence in the last 20 to 30 years were illustrated. Significant reductions in prevalence in individuals over the age of 65 were also illustrated in the UK (~22%) and in Zaragoza, Spain (~43%). Studies from Stockholm and Rotterdam indicated decreases in age-specific dementia incidence.
“The suggested decrease in dementia occurrence coincides with improvements in protective factors (such as education and living conditions) for dementia and a general reduction in risk factors (such as vascular diseases) over recent decades,” explained Brayne. “Incidence and deaths from major cardiovascular diseases have decreased in high-income countries since the 1980s. We are now potentially seeing the results of improvements in prevention and treatment of key cardiovascular risk factors such as high blood pressure and cholesterol reflected in the risk of developing dementia.”
The researchers reinforce however that although the decrease in the occurrence of dementia is a positive sign, the care of individuals with dementia will continue to remain a key challenge due to population ageing. “It is important to remember that the number of people over age 85 is the fastest growing age demographic, with about 40% currently estimated to be affected by dementia,” explained co-author Yu-Tzu Wu (University of Cambridge).
Professor Brayne concluded: “Our up-to-date evidence suggests a relatively optimistic picture of possible future trends in dementia occurrence and strengthens the need to shift more of our societal and research focus to primary prevention across the lifecourse, with a rebalancing from what could be seen as the current overemphasis on diagnostics and drug interventions for dementia (which detect early or later assumed pathology). Policies which address determinants of health in earlier life stages and enhance cognitive reserve for populations may have the greatest long term impact on reduction of dementia risk at given ages in later life as well as on population health more generally.”
Source: The Lancet Neurology via EurekAlert! http://www.eurekalert.org/pub_releases/2015-08/tl-tln081915.php