Memory problems can begin from age 4515 years earlier than previously thought
Mental decline can start in middle-age, according to new research.
The brain's capacity for memory, reasoning and comprehension, known as cognitive function, tends to worsen from age 45 onwards, a study of more than 7,000 adults found.
Previous research has suggested that cognitive decline does not begin before the age of 60, although this was not universally accepted by experts.
The researchers, led by Archana Singh-Manoux from the Centre for Research in Epidemiology and Population Health in France and University College London, say this is the first study to show that a deterioration in memory and thinking skills begins in middle-age.
The researchers studied 5,198 male and 2,192 female civil servants, aged between 45 and 70, over a 10 year period from 1997.
The participants memory, vocabulary and comprehension skills were assessed three times during the study period.
Cognitive tasks included recalling in writing as many words beginning with “S” - phonemic fluency - and as many animal names - emantic fluency - as possible.
The study also took into account the differences in levels of education of the participants.
Cognitive scores declined in all the categories - memory, reasoning and comprehension - except vocabulary, and there was faster decline in older people.
After 10 years, the research showed a 3.6% decline in mental reasoning in men and women who were aged 45 to 49 at the start of the study.
The study also found a 9.6% decline in mental reasoning in men and a 7.4% decine in women aged 65 to 70 at the start of the study.
Writing in the online version of the British Medical Journal, the researchers said conditions such as dementia are now thought to be caused by long-term changes which occur over 20-30 years, and that there is emerging evidence to support "what is good for our hearts is also good for our heads."
Targeting people with risk factors for heart disease such as obesity, high blood pressure and high cholesterol levels may help to lower their risk of dementia later in life as well as protecting their heart, they said.
Dr Anne Corbett, of 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.
This article was published on Fri 6 January 2012
Image © M. Dykstra - Fotolia.com
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