Population-based and epidemiologic studies show that certain modifiable risk factors can increase the risk of cognitive decline and possibly dementia. A growing body of evidence shows that healthy behaviors can protect and promote brain health.
State of science
The Alzheimer’s Association regularly reviews and monitors evidence on modifiable risk factors. The following chart shows risk factors that have low, moderate or high levels of evidence for cognitive decline, dementia, or both. For each risk factor, we categorized the evidence as it relates to both cognitive decline and dementia, based on published population-level, epidemiological studies and reports. We use a lens that combines science, public health, and opportunity for intervention. That is, we look at the strength of the scientific evidence from a population-level perspective with the availability of interventions.
- Strong: consistent evidence of a causal relationship, including intervention studies that suggested modification of risk is possible.
- Moderate: some evidence (reproduced in multiple studies) of either a causal relationship or positive effect of interventions.
- Lower: some relationship, but studies are limited in number, scope, and/or strength – and/or have some contradictory findings.
- Unclear: Emerging areas of research and/or areas with currently unclear relationships.
| |
Cognitive Decline |
Dementia |
| Formal Education (+) |
STRONG |
STRONG |
| Traumatic Brain Injury |
STRONG |
STRONG |
| Midlife Hypertension |
STRONG |
MODERATE |
| Midlife Obesity |
STRONG |
MODERATE |
| Diabetes |
STRONG |
MODERATE |
| Physical Activity (+) |
STRONG |
MODERATE |
| Smoking |
STRONG |
MODERATE |
| Sleep Disorders/Poor Quality |
STRONG |
MODERATE |
| Balanced Nutrition (+) |
MODERATE |
LOWER |
| Cognitive Engagement (+) |
MODERATE |
LOWER |
| Air Pollution |
LOWER |
LOWER |
| Social Isolation |
LOWER |
UNCLEAR |
| Depression |
LOWER |
UNCLEAR |
| Hearing Loss |
LOWER |
UNCLEAR |
| Moderate Alcohol Use (+) |
LOWER |
UNCLEAR |
| Hyperlipidemia |
UNCLEAR |
UNCLEAR |
| Alcohol Abuse |
UNCLEAR |
UNCLEAR |
| Substance Abuse |
UNCLEAR |
UNCLEAR |
Note: This chart is not a review and evaluation of clinical evidence. It is based on population-based, epidemiological evidence. While physicians can use it to guide discussions with patients, it is primarily meant to drive what needs to be addressed at the community level to lower risk and improve brain health.
Addressing modifiable risk factors
Based on the current state of the science, the following healthy behaviors can help address the modifiable risk factors with the strongest levels of evidence. Combining these behaviors can help maximize benefits for the brain and overall health.
- Continuing with formal education for as long as possible (adults and children)
- Preventing head injuries through appropriate helmet/seatbelt use and addressing fall risks
- Preventing and controlling hypertension through medication and healthy habits
- Maintaining a healthy weight
- Preventing or managing Type II diabetes through healthy habits and medication
- Increasing physical activity
- Not smoking or quitting smoking
- Addressing sleep disorders to achieve better quality sleep
- Getting balanced nutrition
- Staying cognitively engaged with new and challenging tasks
Risk reduction and brain health resources
For medical professionals
These BOLD Center of Excellence on Risk Reduction resources advance understanding of cognitive decline and dementia risk factors.
To share with patients and care partners
The following resources are available to share with patients and care partners to promote brain health as well as how to have conversations about signs of memory loss or other changes.