Delaying retirement could help stave off Alzheimer's and other types of dementia, a study of over 400,000 French found.
Presented at the Alzheimer's Association International Conference in Boston, the study found that for every additional year of work, a person's risk of developing dementia decreased by 3.2 percent.
The records used included 429,000 workers, most of whom were either shopkeepers or craftsmen of some type, such as bakers or woodworkers. On average, those examined were 74 and had been retired for 12 years.
Of the total number, nearly 3 percent had developed some kind of dementia; however, the risk varied depending on when people had decided to leave work. Those who retired at 65, for example, showed about a 15 percent lower risk of developing dementia compared to someone who retired at 60, even after other factors were taken into account.
In order to determine that mental decline wasn't the reason people retired in the first place, researchers conducted analyses that effectively eliminated people who developed dementia in the years just following their retirement.
As the largest study of its kind, researchers say the conclusion makes sense: working usually entails higher levels of physical activity, social connectedness and mental challenge, all of which are known to help prevent mental decline.
However, for those forced to retired, all is not necessarily lost: a recent study of nearly 300 people showed that reading, writing or solving puzzles at any age helps to keep the brain fit.
According to the World Health Organization, roughly 35.6 million people worldwide currently live with dementia, with 7.7 million new cases occurring every year. The most common cause is Alzheimer's disease, which is estimated to cause between 60 percent and 70 percent of cases.