The brain´s capacity for memory, reasoning and cognitive function can start deteriorating as early as age 45, instead of age 60, as experts had previously thought, according to new research published in the British Medical Journal.
Researchers, led by Archana Singh-Manoux from the Center for Research in Epidemiology and Population Health in France and University College London in the UK, argue that it is important to investigate the age at which cognitive decline begins because medical interventions are more likely to work when individuals first start to experience mental impairment.
Singh-Manoux and colleagues observed 5,198 men and 2,192 women over a ten year period from 1997 to 2007. Volunteers of the study were London civil servants aged between 45 and 70 who had been enrolled in the Whitehall II cohort study established in 1985.
Cognitive functions of the participants were assessed three times over the study period. Individuals were tested for memory, vocabulary and aural and visual comprehension skills. The latter included recalling and writing as many words beginning with “S” and as many animal names as possible.
The results showed that cognitive scores declined in all categories except vocabulary and there was faster decline in older people. The authors of the study accounted for differences in education level when the tests were conducted.
The researchers found a 3.6 percent decline in mental reasoning in men aged 45 to 49 and a 9.6 percent decline in those aged 65 to 70. In women, the results were 3.6 percent and 7.4 percent, respectively.
The authors argue that robust evidence showing cognitive decline before the age of 60 has important ramifications because it demonstrates the importance of promoting healthy lifestyles, particularly cardiovascular health, as there is emerging evidence that “what is good for our hearts is also good for our heads.”
In an accompanying editorial, Francine Grodstein, Associate Professor of Medicine at Brigham and Women’s Hospital in Boston, said the study “has profound implications for prevention of dementia and public health.” She added that further creative research needs to be undertaken.
The Alzheimer´s Society said research was also needed into how changes in the brain could help dementia diagnoses.
“There are things people can do to reduce their chances of getting dementia later down the line,” Dr. Anne Corbett from the Alzheimer´s Society told BBC News. “We now need to look at who experiences cognitive decline more than the average and how we stop the decline. Some level of prevention is definitely possible.”
“Rates of dementia are going to soar and health behaviors like smoking and physical activity are linked to levels of cognitive function,” she added. “It´s important to identify the risk factors early. If the disease has started in an individual’s 50s but we only start looking at risk in their 60s, then how do you start separating cause and effect?”
Dr. Simon Ridley, head of research at Alzheimer´s Research UK, said he wanted to see similar studies carried out in a wider population sample.
“Previous research suggests that our health in mid-life affects our risk of dementia as we age, and these findings give us all an extra reason to stick to our New Year´s resolutions,” he told BBC News. “Although we don´t yet have a sure-fire way to prevent dementia, we do know that simple lifestyle changes – such as eating a healthy diet, not smoking, and keeping blood pressure and cholesterol in check – can all reduce the risk of dementia.”
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