Ageing study: A major new study has found that general good health does not reduce the risk of developing dementia in later life.
The study of more than 13,000 people in five different locations in England and Wales found practically no variation in dementia rates even when comparing areas with very different health profiles. One of the study's authors, Dr Fiona Matthews, said previous single-site studies had suggested that people at risk of developing cardiovascular disease, who had poorer health generally, were also at greater risk of developing dementia.
"We expected to see some difference between rural and urban areas, where the health profile is very different, but there is just not any real difference in the pattern we saw in those areas," she said.
For example, rates of dementia in Newcastle, a city where people suffer poorer health and higher mortality than in other areas of England, were not significantly different than rates in rural Wales, where general health is much better.
These findings from the Medical Research Council Cognitive Function and Ageing study based at Cambridge University are published today in the Public Library of Science Medicine.
Studies in the past have found that dementia rates vary between countries although a clear variation has not been shown in western countries. This is the first study of its kind within a single country.
Study co-author Prof Carol Brayne said one possible reason for the findings was that lifestyle differences and variations in mortality across England and Wales were not sufficiently great to influence the incidence of dementia, whereas the different dementia rates between countries in parts of the world were large enough to be easily detectable.
The study found that in people aged 75-79 years, one in 70 will develop dementia but in people aged over 85, this increases to one in 15. Because the population of older people is set to increase significantly, the incident of dementia is set to rise accordingly.
Paul Murray of Age Action Ireland said it was estimated that there were 30,000 people with dementia in Ireland. He said there was an urgent need for more resources to provide services for people with dementia, including day hospitals and respite care.