Nearly half of dementia cases may be linked to potentially modifiable risk factors, including smoking and high blood pressure. New research from Lund University has examined how specific dementia risk factors are associated with Alzheimer’s disease and vascular dementia, the two most common causes of dementia.
Some dementia risk factors cannot be changed, including age, sex and genetics. However, other factors may be modified through lifestyle changes or medical treatment. These include smoking, cardiovascular disease, high blood lipid levels, physical inactivity, alcohol consumption, hearing loss and high blood pressure.
Dementia is not a single disease. It describes a group of symptoms caused by different disorders, meaning that risk factors may vary according to the underlying form of dementia. Researchers at Lund University studied how individual risk factors were associated with brain changes linked to Alzheimer’s disease and vascular dementia.
“Much of the existing research on modifiable dementia risk factors does not distinguish between the different causes of dementia. As a result, we have had limited knowledge about how individual risk factors influence the underlying disease processes in the brain,” explains Sebastian Palmqvist, senior lecturer in neurology at Lund University and senior physician at the Memory Clinic at Skåne University Hospital.
Researchers Tracked Brain Changes for Four Years
The study included nearly 500 adults with an average age of 65 who had no signs of cognitive impairment at the beginning of the research. Participants were followed for four years, with researchers measuring changes in the brain’s white matter—the nerve fibers that are frequently damaged in vascular dementia.
The research team also measured levels of amyloid beta and tau, two proteins strongly associated with Alzheimer’s disease. The researchers aimed to determine how modifiable and nonmodifiable risk factors were linked to changes in the brain over time.
Vascular Risk Factors Were Linked to White Matter Damage
Most of the modifiable risk factors examined—including smoking, cardiovascular disease, high blood lipid levels and high blood pressure—were associated with damage to the brain’s blood vessels. These factors were also linked to a faster buildup of white matter changes.
“We found that most modifiable risk factors—including smoking, cardiovascular disease, high blood lipid levels and high blood pressure—were associated with damage to the brain’s blood vessels and a faster accumulation of white matter changes. This damage can impair blood vessel function, contribute to vascular brain injury and ultimately increase the risk of vascular dementia,” says Isabelle Glans, doctoral student at Lund University and resident in neurology at Skåne University Hospital.
The researchers also found possible links between certain risk factors and the proteins associated with Alzheimer’s disease.
“Diabetes was associated with greater accumulation of amyloid beta, while people with a lower body mass index had faster tau accumulation. However, these findings require further investigation and confirmation in future studies,” Isabelle Glans adds.
Healthy Habits May Help Reduce Multiple Types of Brain Damage
Adopting healthier habits and managing modifiable dementia risk factors may help delay the development of Alzheimer’s symptoms. This could be particularly important because many people with dementia experience more than one disease process in the brain, including both vascular damage and Alzheimer’s-related changes.
Palmqvist said that improving cardiovascular and metabolic health may remain beneficial even for people who are at increased risk of Alzheimer’s disease.
“Addressing vascular and metabolic risk factors may help reduce the combined impact of multiple brain changes that can occur at the same time,” he concludes.
Source: www.sciencedaily.com