Mental decline begins at 45, according to new research By MARTYN McLAUGHLIN Published on Friday 6 January 2012 00:00 ADULTS could begin to lose their ability to remember, reason and comprehend information as early as their mid-40s, according to landmark new research. The study found people as young as 45 began to suffer a loss in memory and mental reasoning, prompting calls for a rethink over the way medicine can prevent dementia. The research, which experts said spells out "profound implications" for the treatment of memory loss, suggests the age at which people can begin to lose certain faculties is much lower than previously thought. Until now, many scientists have thought that the brain's decline does not begin before the age of 60, although such a view has never been universally accepted. But the researchers from the Centre for Research in Epidemiology and Population Health in France and University College London (UCL) believe the middle-aged could be affected by such a loss of mental function. Published online in the British Medical Journal (BMJ), the research focused on civil servants aged between 45 and 70 at the start of cognitive testing in 1997 to 1999. Scientists studied more than 7,000 people over a ten-year period, with cognitive function measured three times over the course of the decade to assess memory, vocabulary, hearing and visual comprehension skills. Tasks included recalling in writing as many words beginning with the letter S as possible and as many animal names as could be thought of. Differences in education level were also taken into account. All cognitive scores, except vocabulary, declined among all age groups during the study, and there was evidence of faster decline among older people. In men, there was a 3.6 per cent drop in reasoning after ten years among those who were aged 45 to 49 at the start of the study and 9.6 per cent among those aged 65 to 70. In women, the decline was 3.6 per cent and 7.4 per cent in the same age groups respectively. The authors concluded: "Cognitive decline is already evident in middle age (45-49). Life expectancy continues to increase, and understanding cognitive ageing will be one of the challenges of this century. Poor cognitive status is perhaps the single most disabling condition in old age. The researchers, led by Dr Archana Singh-Manoux from UCL's department of epidemiology and public health, said diseases such as dementia were now thought to be the result of long-term changes over at least 20 to 30 years. In an accompanying editorial in the BMJ, Francine Grodstein, associate professor of medicine at Brigham and Women's Hospital in the US, said the study of 5,198 men and 2,192 women "has profound implications for prevention of dementia and public health." However, she said that more creative research, perhaps using telephone and computer cognitive assessments, needs to be undertaken. Dr Anne Corbett, research manager at the Alzheimer's Society, said: "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, nor how feasible it would be for GPs to detect these early changes.  Dr Simon Ridley, head of research at Alzheimer's Research UK, said: "Although this study didn't look at dementia, it would be important to follow up these participants to see which people go on to develop the condition."