Scientists believe that working later in life may help keep Alzheimer's disease at bay.
Researchers at the Institute of Psychiatry at King's College London came up with proposition after analysing data from 1,320 dementia patients, including 382 men.
The researchers found that continuing to work even in old age helped men to keep their brains sharp enough to delay dementia.
Dementia is caused by the mass loss of cells in the brain, and experts believe one way to guard against it is to build up as many connections between cells as possible by being mentally active throughout life. This is known as a "cognitive reserve".
While a good education is known to be associated with a reduced dementia risk, the latest study suggests that mental stimulation continued into later years may also have a positive effect.
The study showed that people who retired late developed Alzheimer's at a later stage than those who opted not to work on.
According to the researchers, each additional year of employment was found to linked with around a six week later age of onset.
"The possibility that a person's cognitive reserve could still be modified later in life adds weight to the "use it or lose it" concept where keeping active later in life has important health benefits, including reducing dementia risk," the BBC quoted researcher Dr. John Powell as saying.
Researcher Professor Simon Lovestone said: "The intellectual stimulation that older people gain from the workplace may prevent a decline in mental abilities, thus keeping people above the threshold for dementia for longer."
He, however, added: "Much more research is needed if we are to understand how to effectively delay, or even prevent, dementia."
A research article on the study, funded by the Alzheimer's Research Trust, has been published in the International Journal of Geriatric Psychiatry.