As life expectancies increase, the number of people living with dementia worldwide continues to rise. The 2024 report of the Lancet Commission on dementia prevention, intervention, and care adds compelling new evidence that untreated vision loss and high LDL cholesterol are risk factors for dementia.
Overall, around 45% of cases of dementia are potentially preventable by addressing 14 modifiable risk factors at different stages during the life course.
During Early Life
Not completing secondary education
Low educational attainment can make people more vulnerable to cognitive decline. In contrast, lifelong learning is associated with improved brain health and higher levels of cognitive activity.
During Midlife
Hearing loss
Hearing loss is related to an increased risk of developing dementia and may be an early symptom. The good news is hearing loss may be corrected with the use of hearing aids. A recent analysis of four studies reported that people with hearing loss who used hearing aids had a significantly lower risk of cognitive decline and dementia.
High LDL cholesterol
Excess brain cholesterol is associated with increased risk of stroke and deposition of Alzheimer’s disease-related pathology.
Depression
Depression may heighten dementia risk by increasing stress hormones, decreasing levels of proteins that are good for brain cells, and shrinking the hippocampus, a brain region critical for forming memory. People who were treated for depression by medication, psychotherapy, or combination therapy were less likely to develop dementia than people with depression who received no treatment.
Traumatic brain injury
Traumatic brain injury is caused by car/motorcycle/bicycle accidents, military incidents, boxing, other contact sports, and falls.
Physical inactivity
Research has shown that people who take regular exercise may be up to 20% less likely to develop dementia than those who don’t take regular exercise.
Diabetes
Newer evidence suggests that a midlife onset of type 2 diabetes is significantly associated with higher dementia risk, while late-life onset is not. It is possible that the longer duration of illness and poorly controlled diabetes may increase the risk of dementia.
Smoking
The good news is that quitting smoking can reduce one’s risk of dementia, as some studies report no increased risk in former smokers.
Hypertension
Hypertension can be managed through diet, lifestyle changes, and medications.
Obesity
Obesity is more common in people who do not get enough physical activity and is associated with increased risk for diabetes and hypertension, all of which are linked with increased dementia risk.
Excessive alcohol consumption
An analysis of 28 systematic reviews concluded that heavy alcohol use was associated with a higher risk of dementia and changes in brain structures.
During Late Life
Social isolation
Social isolation may result in decreased cognitive activity, which may accelerate cognitive decline and poor mood.
Air pollution
Although air pollution cannot be entirely avoided, there are steps you can take to reduce your exposure, such as monitoring air pollution levels online or with apps and stay indoors on days with particularly high air pollution. You can also limit exposure to car exhaust by closing vents and windows while in heavy traffic.
Untreated visual loss
Uncorrected vision loss increases a person’s risk of developing dementia. People who have corrected vision loss do not have an increased risk of developing dementia. A study in the US reported that people with cataract who had cataract extraction had a significantly lower dementia risk compared to those who did not have cataract extraction, highlighting the importance of treating vision impairment.
