Participants filled out questionnaires at the beginning of the study, including one on physical activities. They were asked how often they participated in activities such as climbing a flight of stairs, walking, and participating in strenuous sports. They were also asked about household chores, job-related activities, and what kind of transportation they used, including walking or biking to work.
Participants completed another questionnaire on mental activities. They were asked about their education level, whether they attend adult education classes, how often they visit with friends and family, visit pubs or social clubs or religious groups, and how often they use electronic devices such as playing computer games, watching TV, and talking on the phone.
Additionally, participants reported whether they had any immediate family members with dementia. This helped researchers determine if they had a genetic risk for Alzheimer’s disease. Study participants were followed an average of 11 years. At the end of the study, 5,185 people had developed dementia.
After adjusting for multiple factors such as age, income, and smoking, researchers found that most physical and mental activities studied showed links to the risk of dementia. Importantly, the findings remain after considering the high correlations and interactions of these activities. People who were highly engaged in activity patterns including frequent exercises, household chores, and daily visits of family and friends had 35%, 21%, and 15% lower risk of dementia, respectively, compared to people who were the least engaged in these activity patterns.
Researchers also looked at dementia incidence rates by identified activity patterns. The rate in people who exercised frequently was 0.45 cases for every 1,000 person-years compared to 1.59 for people who rarely exercised. Person-years take into account the number of people in a study as well as the amount of time spent in the study. Those who frequently did household chores had a rate of 0.86 cases for every 1,000 person-years compared to 1.02 for people who rarely did household chores. People who visited family daily had a rate of 0.62 cases for every 1,000 person-years compared to 0.8 cases for those who only visited friends and family once every few months.
“Our study has found that by engaging more frequently in healthy physical and mental activities people may reduce their risk of dementia,” Song said. “More research is needed to confirm our findings. However, our results are encouraging that making these simple lifestyle changes may be beneficial.”
The researchers found that all participants benefited from the protective effect of physical and mental activities, whether or not they had a family history of dementia.
A limitation of the study was that people reported their own physical and mental activity, so they may not have remembered and reported these activities correctly.