Follow-up studies of surveys taken by Scottish schoolchildren in 1932 and 1947 give researchers a unique insight into cognitive ageing.
Given the rapidly increasing number of older people worldwide, there is a growing interest in what contributes to health and wellbeing in old age.
Identifying what happens in the brain as we age is one of the greatest challenges to improving the health of older people. Not everyone experiences cognitive decline in the same way but it is rare to be able to study this properly.
The Lothian Birth Cohorts included children born in 1921 and 1936. These children were assessed using the Scottish Mental Surveys of 1932 and 1947 when they were aged 11.
Professor Deary and his team managed to track down over a thousand surviving participants who took the same Scottish Mental Survey test at age 70 which they had been given at age 11.
The team then carried out modern cognitive tests, which looked at reasoning, memory and information processing. Members underwent physical fitness testing and completed questionnaires on personality, diet and life experiences. They also provided blood samples for DNA testing. Tests were repeated over several years.
From this unique data the team was able to examine many different factors which contribute to age-related changes. These range from genetic and medical factors to lifestyle. Childhood cognitive ability scores have also been used to predict health throughout life. Children with higher mental capabilities live longer. They are less likely to develop heart disease and dementia. They are also less likely to take up smoking and other harmful lifestyle choices.