Want to cut your risk of developing dementia? Indulge in activities such as reading a book and doing yoga and spend your time with family and friends, suggests a new study.

Published in the journal Neurology, the meta-analysis involving a review of 38 studies from around the world involving a total of more than 2 million people who did not have dementia revealed that leisure activities overall were linked to a reduced risk of the neurodegenerative disease.

Those who engaged in leisure activities had a 17 per cent lower risk of developing dementia than those who did not engage in them. Mental activity mainly consisted of intellectual activities and included reading or writing for pleasure, watching television, listening to the radio, playing games or musical instruments, using a computer and making crafts.

People who participated in these activities had a 23 per cent lower risk of dementia, said researchers at Peking University Sixth Hospital in China. Physical activities included walking, running, swimming, bicycling, using exercise machines, playing sports, yoga, and dancing. Researchers found that people who participated in these activities had a 17 per cent lower risk of dementia.

Social activities mainly referred to activities that involved communication with others and included attending a class, joining a social club, volunteering, visiting with relatives or friends, or attending religious activities. Researchers found that people who participated in these activities had a 7 per cent lower risk of dementia.

"This meta-analysis suggests that being active has benefits, and there are plenty of activities that are easy to incorporate into daily life that may be beneficial to the brain," said Lin Lu from Peking.

"Our research found that leisure activities may reduce the risk of dementia. Future studies should include larger sample sizes and longer follow-up time to reveal more links between leisure activities and dementia," Lu said.

The study participants were followed for at least three years. During the studies, 74,700 people developed dementia. A limitation of the study was that people reported their own physical and mental activity, so they may not have remembered and reported the activities correctly.