Using computers, playing crosswords, and games like chess can prevent older people from developing dementia more than knitting, painting, or socialising, according to a study.

Published in JAMA Network Open, the findings may help older individuals and aged care professionals plan more targeted approaches to reducing dementia risk.

Researchers drew data from 10,318 Australians aged 70 and older. They found that participants who routinely engaged in adult literacy and mental acuity tasks such as education classes, keeping journals, and doing crosswords were 9-11 per cent less likely to develop dementia than their peers.

Creative hobbies like crafting, knitting, painting, and more passive activities like reading reduced the risk by 7 per cent.

In contrast, the size of someone's social network and the frequency of external outings to the cinema or restaurant were not associated with dementia risk reduction.

The results remained statistically significant even when adjusted for earlier education level, and socioeconomic status. No significant variations were found between men and women.

In 2022, 55 million people globally lived with dementia, with 10 million new cases yearly.

Senior author Associate Professor Joanne Ryan, from Monash University’s School of Public Health and Preventive Medicine, said identifying strategies to prevent or delay dementia was a huge global priority.

"We had a unique opportunity to close a gap in knowledge by investigating a broad range of lifestyle enrichment activities that older adults often undertake, and assess which of those were most strongly aligned with avoiding dementia," Professor Ryan said.

"I think what our results tell us is that active manipulation of previously stored knowledge may play a greater role in dementia risk reduction than more passive recreational activities. Keeping the mind active and challenged may be particularly important."

Professor Ryan said the results did not rule out that those naturally drawn to the types of leisure activities linked to cognitive health also had specific personality traits that were otherwise beneficial, or they may generally have had better health behaviours.