Why DELAYING retirement can make you less likely to develop dementia Those retiring at 65 are 15 per cent less likely to suffer from the condition than those retiring at 60, finds authoritative French study Get to work Grandma: New research carried out in France suggests that delaying retirement can make people less likely to develop dementia It is the dream of many to be successful enough in their professional life to retire early and enjoy their golden years in a splendid state of carefree relaxation. But new research suggests that delaying retirement can make people less likely to develop dementia. A French study believed to be the largest ever of its kind found someone retiring at 65 was about 15 per cent less likely to develop the condition that someone retiring at 60. The findings back up previous studies suggesting that continued intellectual stimulation and mental engagement may ward off the tragic cognitive decline caused by Alzheimer's and similar illnesses. They suggest professional activity may be an important determinant of intellectual stimulation and mental engagement, which are thought to be potentially protective against dementia. Study author Carole Dufoil and her team at the Institut National de la Santé et de la Recherché Médicale (INSERM) analysed the health and insurance records of more than 429,000 self-employed workers. Analyses showed that the risk of being diagnosed with dementia was lower for each year of working longer. Even after excluding workers who had dementia diagnosed within the 5 years following retirement, the results remained unchanged and highly significant, the researchers said in a release. 'Our data show strong evidence of a significant decrease in the risk of developing dementia associated with older age at retirement, in line with the "use it or lose it" hypothesis,' said Dr Dufouil. The patterns were even stronger when we focused on more recent birth cohorts. Around 35million people worldwide suffer from dementia, with Alzheimer's the most common type, CBS News reported. The illness is expected to become a particularly acute problem in Western nations in coming decades as members of the baby boom generation reach their dotage. But with retirement ages being delayed in many countries worried about the impact of so many new pensioners on social security safety nets, it appears it could have the unintended consequence of actually keeping them healthy for longer. Tragic cognitive decline: An elderly woman suffering from Alzheimer's disease in a residential care home. Around 35million people worldwide suffer from dementia, with Alzheimer's the most common type Dr Dufouil, director of research in neuroepidemiology at INSERM, said: 'Professional activity may be an important determinant of intellectual stimulation and mental engagement, which are thought to be potentially protective against dementia. As countries around the world respond to the aging of their populations, our results highlight the importance of maintaining high levels of cognitive and social stimulation throughout work and retired life, and they emphasize the need for policies to help older individuals achieve cognitive and social engagement. The researchers presented their findings today at the Alzheimer's Association International Conference in Boston, Massachusetts.