A human's ability to remember data, to reason, and understand things properly can start to worsen at the age of 45 years, and not 60 as many had believed, researchers from France and the United Kingdom reported in the BMJ (British Medical Journal). According to prior studies, cognitive decline, if it does occur, will generally not do so before the age of sixty. Many experts had wondered whether the deterioration might not start sooner.
Study leader, Archana Singh-Manoux, at the Centre for Research in Epidemiology and Population Health, France, and researchers from University College London in the UK, believe that..:
"..understanding cognitive aging will be one
of the challenges of this century."
The authors stress that identifying cognitive decline onset is crucial for effective medical interventions. In other words, the earlier-on cognitive deterioration can be spotted, the better medical treatments tend to be.
Singh-Manoux and team observed 2,192 females and 5,198 males from 1997 to 2007. All the subjects were civil servants aged from forty-five to seventy years - they formed part of the Whitehall II cohort study (a UK study), which had started in 1985.
Over the ten-year period, all study-participants had their cognitive functions assessed. This included testing for:
- Aural comprehension skills (listening skills)
- Visual comprehension skills. The journal cites as examples, remembering as many words as possible that started with the letter "S" (phonemic fluency), or recalling as many animal names as possible (semantic fluency).
Factors which might impact on their findings were taken into account, such as the participant's level of education.
They found that cognitive scores dropped in all categories, except for vocabulary. The older the participant, the faster their decline was likely to be.
From 1997 to 2007, mental reasoning among the males aged 45-49 dropped by 3.6%, and 9.6% in the 65-70 age group (males). Among females, the decline was 3.6% for those aged 45-49, and 7.4% among those aged 65-70.
The authors wrote:
"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'."
There are certain risk factors linked to cognitive decline, such as hypertension, obesity, and high cholesterol levels. Targeting patients with known risk factors might not only protect their hearts, but also prevent dementia from developing later on.