Dementia incidence in people aged 65 years and over in the UK has dropped by 20 per cent since the early 1990s, according to the MRC Cognitive Function and Ageing study. The increase in dementia over this time is “far smaller … than would have been expected from extrapolation of earlier estimates”, says the study.
Between 1990 and 1995, researchers interviewed 5,156 people aged 65 years and older in Cambridgeshire, Newcastle and Nottingham at baseline and then two years later. In 2008-13, they interviewed 5,288 people using the same geography and methods.
Dementia incidence was 20.0 and 17.7 per 1,000 person years in 1990-5 and 2008-13 respectively. The rate fell from 10.3 to 5.0 per 1,000 person years respectively in men aged 65-69 years and from 12.9 to 8.7 per 1,000 person years in those aged 70-74 years. Rates also fell in men aged 75-79 years (20.4-16.7 per 1,000 person years), 80-84 years (42.4-24.8) and 85 years and older (71.5-38.0).
In women, the rate fell from 6.3 to 4.6 per 1,000 person years in those aged 65-69 years and from 7.4 to 6.4 per 1,000 person years at ages 70-74 years. Rates fell for those aged 75-79 years (17.6-16.1 per 1,000 person years), rose in those aged 80-84 years (35.6-39.6) and fell in women 85 years and older (59.5-55.3). Dementia incidence was higher in people from more deprived areas.
In the second survey, the rates were 14.0 per 1,000 person years in the least deprived area and 20.6 per 1,000 person years in the most.
Based on the first survey, the authors estimated that 183,000 people develop dementia each year in the UK. Assuming no alteration in incidence and with demographic changes, the number of new cases would be expected to reach 251,000 annually in 2015. The new data suggests the true figure is 209,600: approximately 74,000 men and 135,000 women.
While changing diagnostic criteria are increasing the numbers identified with dementia, measures that improve health – including education, smoking reduction, healthy diet and exercise – may reduce risk. Indeed, the greater drop in men than women may reflect changes in smoking habit and vascular health.
“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,” says study author Carol Brayne, director of the Cambridge Institute of Public Health, University of Cambridge.
“While we’ve seen invest-ment in Europe and many other countries, the lack of progress in access to education, malnutrition in childhood and persistent inequalities within and across other countries means that dementia will continue to have a major impact globally. Our evidence shows that the so-called dementia ‘tsunami’ is not an inevitability: we can help turn the tide if we take action now.”
It is all about ‘making every contact count’, as eventually those brief conversations will sink in and the patient will begin to make a change, adds Laura Reed, Numark’s service development manager. “This underlines the potential role for pharmacy, in particular in relation to men’s health, as they will tend to put off going to the GP but may be visiting pharmacies instead.”
(Nature Communications DOI:10.1038/ncomms11398)