Dementia is becoming one of the biggest health challenges facing the world. Experts estimate that the number of people living with dementia could nearly triple by 2050 as populations age and people live longer.
Dementia is not a single disease. Instead, it is a group of conditions that affect memory, thinking, language, and the ability to carry out daily activities. Alzheimer’s disease is the most common form of dementia, accounting for most cases worldwide.
Because there is currently no cure for most forms of dementia, researchers are working hard to find ways to prevent the disease or delay its onset. Over the years, many studies have shown that lifestyle and health factors can influence dementia risk.
Staying physically active, controlling blood pressure, avoiding smoking, maintaining a healthy weight, and managing diabetes are all believed to help protect brain health. However, genetics also plays a major role, and scientists have long wondered whether healthy habits can offset a person’s inherited risk.
A new study from researchers at Kyushu University and RIKEN has provided important clues. The study, published in Alzheimer’s & Dementia: Diagnosis, Assessment & Disease Monitoring, examined whether healthy lifestyle and health-related factors could reduce dementia risk in people with different genetic backgrounds.
The researchers focused on a gene called APOE. This gene helps the body process fats, but one version of it, known as APOE ε4, is strongly linked to a higher risk of Alzheimer’s disease. People inherit one copy of the APOE gene from each parent. As a result, some people carry no APOE ε4 copies, some carry one copy, and others carry two copies.
To investigate the relationship between genes and lifestyle, the researchers analyzed data from 9,605 Japanese adults aged 65 and older who lived in the community. They examined participants’ APOE status and calculated scores based on several lifestyle and health factors that people can potentially improve or control.
The findings showed that genetic risk increased dramatically with the number of APOE ε4 copies a person carried. Individuals with two copies of the gene had more than ten times the risk of developing dementia compared with people who carried none.
However, the study also delivered encouraging news. Among people who carried one copy of the gene or no copies at all, healthier lifestyles and better management of health conditions were linked to a significantly lower risk of dementia.
In other words, maintaining good health appeared to provide meaningful protection for many people, even those with some genetic risk.
The researchers also examined brain scans to better understand what was happening inside the brain. MRI results showed that participants with healthier risk-factor profiles generally had less brain shrinkage and fewer areas of damaged brain tissue. These changes are important because they are often associated with cognitive decline and dementia.
The situation was different for people who carried two APOE ε4 copies. In this group, healthier lifestyles did not appear to significantly reduce dementia risk. Brain scans showed greater brain shrinkage and tissue damage regardless of whether their lifestyle profiles were favorable or unfavorable.
These findings suggest that lifestyle changes remain a powerful tool for dementia prevention for much of the population. Even individuals carrying one copy of the APOE ε4 gene may benefit from controlling risk factors and maintaining healthy habits.
At the same time, the study suggests that people with the highest genetic risk may require additional preventive approaches beyond lifestyle changes alone.
Professor Toshiharu Ninomiya, who led the study, noted that favorable management of health and lifestyle factors may help reduce dementia risk among people carrying one or no APOE ε4 alleles. For those carrying two copies, earlier intervention and new preventive or treatment strategies may be needed.
If you care about brain health, please read studies about low choline intake linked to higher dementia risk, and how eating nuts can affect your cognitive ability.
For more health information, please see recent studies that blueberry supplements may prevent cognitive decline, and results showing higher magnesium intake could help benefit brain health.
Source: Kyushu University and RIKEN.
