Elsewhere, research has shown that fears an Alzheimer’s “explosion” are unfounded and that dementia rates may be stabilising in the United Kingdom and other parts of Europe.
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Researchers at Cambridge University comparing data decades apart has found that the proportion of UK citizens aged over 65 with dementia in 2011 was actually one-fifth lower than predicted.
The studies in the Netherlands and Sweden also showed a fall in the age-specific incidence of dementia, although these finding were not statistically significant. Prevalence in men aged 65 and older went down by about 43% between 1987 and 1996.
This limited evidence may not indicate a continuing trend and we know that there are other risk factors for dementia, such as diabetes, that are increasing.
Jeremy Hughes, chief executive of the Alzheimer’s Society.
Researchers said depression probably showed a slight increase in risk because patients are inclined to carry out less physical and cognitive activity and have less objective in life, which are correlated with risk of developing the disease.
The number of people developing dementia is stabilising, experts say. “It is important to remember that the number of people over age 85 is the fastest growing age demographic, with about 40% now estimated to be affected by dementia”, said her Cambridge co-author Yu-Tzu Wu. The findings suggest that prevalence (ie, the percentage of the population with dementia) and incidence (the number of new dementia cases over a given time) of dementia in specific age groups are falling across time and generations.
“With no cure, few effective treatments and an economic impact exceeding that of cancer or heart disease, dementia remains the most critical health and social care challenge facing the United Kingdom”, he wrote in a comment.
Martin Prince, professor of epidemiological psychiatry at King’s College London, who was not involved in the research, said he would take a more guarded view of the study’s conclusions.
These changes are at odds with previous research that led to dire predictions about an impending dementia epidemic, the researchers said.
Writing in medical journal The Lancet Neurology, they say dementia cases may be falling due to better education and living conditions, and better prevention and treatment of vascular diseases.
“The bottom line is we need more research to learn to prevent and treat dementia, as it is a large problem for our ageing population”.
Just nine key risk factors may account for two-thirds of all Alzheimer’s cases worldwide, a new study suggests.
The strongest evidence suggested a protective effect for the female hormone oestrogen, cholesterol-lowering drugs (statins), drugs to lower high blood pressure, and anti-inflammatory drugs (NSAIDs).
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Folic acid, coffee and vitamins C and E were also associated with helping to stave off the disease, along with current smoking (only amongst Western populations), light-to-moderate drinking (one to three alcoholic drinks a day), stress, and high body mass index (BMI) in late life.
