Having a sense of purpose can lower your risk of developing the memory-robbing illness dementia, new research has suggested.

A new study, published in The American Journal of Geriatric Psychiatry, followed more than 13,000 adults aged 45 and older for up to 15 years.

They answered statements like 'I have a strong sense of direction and purpose in life' with six possible responses from 'strongly agree' to 'strongly disagree'.

Then their answers were scored and averaged to give a number between 1 and 6, and the higher the value the higher their sense of purpose in life.

The US researchers found people with a higher sense of purpose in life were 28 per cent less likely to develop cognitive impairment—including dementia.

This protective effect was seen even when factors like race, ethnicity, education, genetics and depression were taken into account.

'Our findings show that having a sense of purpose helps the brain stay resilient with age,' said Aliza Wingo, lead author of the study, and professor at the UC Davis.

'Even for people with a genetic risk for Alzheimer's disease, sense of purpose was linked to a later onset and lower likelihood of developing dementia.'

They also found those with higher purpose experienced cognitive decline on average 1.4 months later than those without it.

While this is modest, they say it is meaningful in comparison to treatments available to treat the devastating illness.

'While medications like lecanemab and donanemab can modestly delay symptoms of cognitive impairment in Alzheimer's disease, they come with risks and costs,' said Nicholas C. Howard, one of the authors and researchers at UC Davis

'Purpose in life is free, safe and accessible. It's something people can build through relationships, goals and meaningful activities,' he told News Medical Life Sciences.

And while the study didn't ask participants what gave them purpose, previous research has suggested types of activities that can.

These include spending time with family, volunteering, spiritual practices, hobbies and acts of kindness.

However, the researchers add that their findings didn't prove higher purpose lowers rates of dementia.

But Thomas Wingo, co-author and neurologist at UC Davis added: 'What's exciting about this study is that people may be able to "think" themselves into better health.' 

'Purpose in life is something we can nurture. It's never too early—or too late—to start thinking about what gives your life meaning.'

Symptoms of dementia include issues with memory, thinking speed, mental sharpness and quickness, language, understanding, judgement and mood.

But changes in sight, hearing, taste, touch and balance are little-known dementia signs that can strike years before well-known ones appear.

It comes just days after new research revealed problems in the gut could help detect Alzheimer's years before symptoms appear.

Scientists found those with common digestive problems including bowel inflammation and vitamin deficiencies were more likely to suffer memory issues. 

They identified 155 diagnoses related to gut and metabolic disorders and found a number of issues linked to increased risk of Alzheimer's disease.

This included irritable bowel disease (IBD), Chron's disease, ulcerative colitis, acid reflux, diabetes and irritable bowel syndrome (IBS).