A study has found age-related cognitive decline may begin as early as age 45. The ten-year study of Whitehall civil servants, carried out by a team of international scientists in the UK, France and the US, is the first to find signs of cognitive decline in people younger than 60.
Led by researchers at the Centre for Research in Epidemiology and Population Health, in France, and University College London, the team studied 7,390 civil servants working in Whitehall over the course of ten years. The participants were given a range of cognitive tests – including memory, reasoning, vocabulary and language tests – three times over the decade.
The researchers analysed the results by grouping the civil servants into age categories, taking differences in education into account. They found that each age category showed a decline in cognitive ability over the ten years, although this decline was faster in older people. For example, men aged 45-49 showed an average decline in reasoning abilities of 3.6% over ten years, compared to 9.6% in men aged 65-70. In women, the average rate of decline for those aged 45-49 was 3.6%, compared to 7.4% in women aged 65-70.
The results, which are published in the BMJ online, add to previous evidence suggesting that biological changes associated with dementia may start in mid-life – although the cognitive decline seen in this study was subtle compared to the severe decline seen in dementia. The scientists argue that further research is now needed to identify what causes cognitive decline, and suggest focusing on younger people who experience a faster than expected decline for their age group.
Dr Simon Ridley, Head of Research at Alzheimer’s Research UK, said:
“Experts believe that Alzheimer’s disease, the most common cause of dementia, begins to develop in mid-life. 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. It’s important to note that the group studied here was not representative of the population as a whole, and it would be helpful to see similar studies carried out in a wider 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. 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.
“With 820,000 people in the UK affected by dementia, it’s vital that we invest in research to find new ways to prevent and treat this devastating condition.”