Smart youth may avoid dementia, capital study finds PEOPLE who are smarter when they are young may enjoy better mental health in old age, research into the human brain has found. Scientists find link between childhood intelligence and avoiding dementia in later life Research involved 588 people born in 1936 who live in Edinburgh, with IQs compared at age 11 and 70 More than two-thirds of the link between cognitive ability in later life and the brain's cortical thickness could be accounted for by differences in IQ decades earlier in childhood Older people who stay sharp tend to have a thicker brain cortex, the outermost region that includes the areas responsible for judgment and complex thought. Childhood intelligence accounts for why some elderly people have more cortical tissue and better mental capacity, according to the research. It involved 588 people born in 1936 who live in the Edinburgh area and who had their IQs tested at age 11 and again at age 70. When they were 73, they had MRI scans to measure the thickness of their brain cortex. The study found that more than two-thirds of the link between cognitive ability in later life and the brain's cortical thickness could be accounted for by differences in IQ decades earlier in childhood. The research was conducted by the universities of Edinburgh and McGill in Montreal, Canada, and appears in the latest edition of the journal Molecular Psychiatry. Professor Ian Deary, from Edinburgh University's school of philosophy, psychology and language sciences, said: "These findings are all part of our research to understand factors that contribute to healthy cognitive ageing and which apparent causes might actually have more complex explanations. It could be that brain cortical thickness and intelligence are linked right across most of life. If we hadn't had the data on intelligence from childhood, we could have concluded incorrectly that a thicker brain cortex was the driver of successful cognitive ageing. The study was supported by funding from the Age UK charity. The charity's head of research, Professor James Goodwin, said: "This research further extends our knowledge of what are and, perhaps more importantly, what are not the important factors involved in cognitive decline. Only by better understanding the processes involved in cognitive decline can we begin to develop preventions and treatments that will allow us to avoid severe cognitive decline or even dementia. Carers warned of blind spot for dementia victims