Last Updated on April 20, 2016
New research reported in the journal Nature Communications, has estimated a decrease in dementia cases in the UK over the past decade. This suggests that the number of dementia cases in the UK is not growing as fast as might have been predicted in an increasingly ageing population.
The research, A two decade dementia incidence comparison from the Cognitive Function and Ageing Studies I and II reported an estimated 20% drop in the incidence rate of new cases of dementia in the UK from the 1990s to 2011.
As part of the Medical Research Council Cognitive Function and Ageing Study (CFAS), researchers at the University of Cambridge, Newcastle University, Nottingham University and the University of East Anglia interviewed 7,500 people in three regions (Cambridgeshire, Newcastle and Nottingham) between 1991 and 1994, with repeat interviews at two years, to estimate incidence of dementia. 20 years later a new sample of over 7,500 people from the same localities aged 65 and over was interviewed and again with repeat interview two years later.
This is the first time that a direct comparison of incidence across time in multiple areas, using identical methodological approaches, has been conducted in the world.
The researchers found that dementia incidence across the two decades has dropped by 20% and that this fall is driven by a reduction in incidence among men at all ages. The findings suggest that in the UK, there are just under 210,000 new cases per year: 74,000 men and 135,000 women – this is compared to an anticipated 250,000 new cases based on previous levels. Incidence rates are higher in more deprived areas.
Even in the presence of an ageing population, this means that the number of people estimated to develop dementia in any year has remained relatively stable, providing evidence that dementia in whole populations can change. It is not clear why rates among men have declined faster than those among women, though it is possible that it is related to the drop in smoking and vascular health improving in men.
The researchers argue that while influential reports continue to promote future scenarios of huge increases of people with dementia across the globe, their study shows that global attention and investment in reducing the risk of dementia can help prevent such increases.
Professor Carol Brayne, Director of the Cambridge Institute of Public Health, University of Cambridge, said, ‘Our findings suggest that brain health is improving significantly in the UK across generations, particularly among men, but that deprivation is still putting people at a disadvantage. The UK in earlier eras has seen major societal investments into improving population health and this appears to be helping protect older people from dementia. It is vital that policies take potential long-term benefits into account.’
Professor Fiona Matthews from the Institute of Health and Society, Newcastle University and the Medical Research Council Biostatistics Unit, Cambridge added, ‘Public health measures aimed at reducing people’s risk of developing dementia are vital and potentially more cost-effective in the long run than relying on early detection and treating dementia once it is present. Our findings support a public health approach for long-term dementia prevention, although clearly this does not reduce the need for alternative approaches for at-risk groups and for those who develop dementia.’
Dr Rob Buckle, Director of Science Programmes at the Medical Research Council, which funded the study, added, ‘It is promising news that dementia rates, especially amongst men, have dropped by such a significant amount over the last twenty years, and testament to the benefits of an increased awareness of a brain-healthy lifestyle. However, the burden of dementia will continue to have significant societal impact given the growing proportion of elderly people within the UK population and it is, therefore, as important as ever that we continue to search for new ways of preventing and treating the disease. This study does, however, reinforce the importance of long-term, quality studies that create a wealth of data of invaluable resource for researchers.’
Professor Brayne concluded, 'Our evidence shows that the so-called dementia ‘tsunami’ is not an inevitability: we can help turn the tide if we take action now.'
More information is available here and the full research can be read on the Nature Communications website here.