Working until 65 or beyond could postpone the onset of dementia. A study of 382 men found a significant association between later retirement and later onset of Alzheimer’s disease.

The research supports previous theories that keeping the mind active for as long as possible can help to postpone mental decline. In contrast to earlier studies, however, the researchers found that the quality or duration of the men’s education or the type of work they did had no impact on the age of onset of the disease.

The team from Cardiff University and the Institute of Psychiatry, King’s College London, identified men with “probable” Alzheimer’s disease from clinical databases from the Medical Research Council and Alzheimer’s Research Trust.

They compared their retirement dates and found that every extra year worked postponed the onset of dementia symptoms by nearly six weeks.

The National Institute for Economic and Social Research has suggested that the official retirement age be raised to 70 within a decade to mitigate the effects of government debt.

Publishing their findings today in the International Journal of Geriatric Psychiatry, the study authors say that the association between later retirement age and later Alzheimer’s onset was “significant”.

But, they add, there could be several explanations for this, including previous ill health having influenced a decision to retire. Further studies were needed across a wider group of people to confirm the findings, they said.

The Alzheimer’s Society said: “There could be a number of reasons why later retirement in men is linked with later onset of dementia. Men who retire early often do so because of health conditions, such as hypertension or diabetes, which increase your risk of dementia. It could also be that working helps keep your mind and body active, which may reduce risk of dementia.

“The best way to reduce your risk of dementia is to combine keeping physically active, with eating a balanced diet and getting your blood pressure and cholesterol checked regularly.”

There are 700,000 people in Britain with dementia, 417,000 of whom suffer from Alzheimer’s disease. It is expected that a further one million people will develop dementia in the next ten years.

The average age of retirement for the men in the study was 63.3 years. The average age of onset of Alzheimer’s was 75.6 years.

Simon Lovestone, scientific adviser to the Alzheimer’s Research Trust and the paper’s co-author, 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. Much more research is needed if we are to understand how to delay, or even prevent, dementia.”

Rebecca Wood, chief of the research trust, which funded the study, said: “More people than ever retire later in life to avert financial hardship, but there may be a silver lining: lower dementia risk. Much more research into lifestyle factors is needed if we are to whittle down the £17 billion a year that dementia costs our economy.”

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