Cognitive function can begin to decline from the age of 45, according to new research. There is a 3.6 per cent decline in mental reasoning in women and men aged between 45 and 49, figures from a joint UK and French study have revealed. Published in the British Medical Journal, the investigation looked at 5,198 men and 2,192 women between the ages of 45 and 70 over a ten-year period from 1997. The cognitive functions, including memory, vocabulary and aural and visual comprehension skills were assessed three times throughout the ten-year period and revealed that mental ability begins to decline earlier than previously thought. Commenting on the research, an Alzheimer's Society spokesperson stated: "This large, important study adds vital information to the debate over when cognitive decline begins. "However, the study does not tell us whether any of these people went on to develop dementia." The Alzheimer's Society calls for further research to investigate how feasible it would be for a GP to detect these early changes and how measurable brain alterations can help improve dementia diagnosis. Following the study, Dan Roberts, a cognitive therapist and founder of danroberts.com, advised that for those worried about memory loss, cognitive exercises are vital in keeping minds active. Find out about dementia care and support services at Barchester care homes.