The UK’s Cognitive Function and Ageing Studies give us a unique insight into the number of people who may be living with dementia. The study was first carried out in the early 1990s and when it was repeated recently in 2010 by a national team led by Professor Carol Brayne of the University of Cambridge, the figures showed a 22% drop in the estimated number of people aged 65 or over living with age-related dementia.
The results also showed that social deprivation mattered with increased levels of dementia age for age in areas with greater social deprivation.
The results of this study are already in use by NHS England, with local systems using these up-to-date estimates to inform the government target of identifying over 60% of the estimated number of affected people in each locality.
Importantly this multidisciplinary and multi- institutional team was able to show from this work that risk for dementia at particular ages can be reduced, probably through factors across the whole of the lifecourse, including lifestyle.
Other studies have shown that many risk factors for dementia have changed across successive generations such as improved education.
Professor Marcus Richards of University College London found evidence from the British birth cohorts to show that formal schooling directly benefits cognitive function, even after allowing for the obvious fact that children of high early cognitive ability are likely to do well in school. He also found that this is equally true of adult education and training, which additionally benefits cognitive function even after taking account of formal schooling as well as prior cognitive ability. A comparison between the British 1946 and 1958 birth cohorts shows that the influence of education on cognitive function is stronger in the younger cohort, which is almost certainly the result of the government raising the school leaving age in the intervening 12 years, resulting in a substantial increase in the proportion of children leaving school with educational qualifications.