Understanding Your Risk for Cognitive Decline

For many, preserving mental sharpness becomes a growing concern as they age. By understanding the risk factors for cognitive decline, we can take proactive steps to promote better brain health. Conditions like Alzheimer’s disease and other dementias are not inevitable. Once we recognize our individual risk factors, we can actively work to improve them.

Key Points

• The risk for cognitive decline arises from controllable and uncontrollable factors alike.

• Age is the primary risk factor for cognitive decline, but it is not the only one.

• Many modifiable risk factors are linked to overall health and lifestyle choices.

• Understanding your risk can help guide your prevention strategies.

It is crucial to recognize that some risk factors for cognitive decline are beyond our control, while others can be influenced by our behavior and choices. We refer to this second category as “modifiable risk factors,” and they present excellent opportunities for action and prevention.

Fixed Risk Factors

1. Age: The most significant risk factor for cognitive decline is advancing age. The prevalence of dementia doubles every five years after age 65.¹
2. Genetics: This risk is not modifiable. Genetic mutations confer destiny: if a person has a causative mutation, they will get Alzheimer’s disease. Other genetic markers, like the APOE ε4 allele, increase the risk of developing Alzheimer's disease.²
3. Family History: Having a first-degree relative with Alzheimer’s disease increases an individual’s risk compared to people who do not have a similar family history. Risk is grossly proportional to the number of affected family members.³
4. Sex: Some studies suggest women may have a higher risk of developing Alzheimer's disease, partly due to longer life expectancy and hormonal factors.⁴

Modifiable Risk Factors

"Modifiable" does not mean easily changeable. Factors like socioeconomic status, healthcare access, and living environment are related to other systemic factors and can be challenging to improve. Many such factors are created by circumstances beyond our control earlier in life.

1.    Education: Lower levels of education are associated with increased dementia risk.  Once formal schooling is completed, ongoing learning throughout life continues to build cognitive reserve. Reading, taking classes, or learning new skills all help keep our brains active and flexible.⁵

2.    Hearing Loss: Untreated hearing loss is linked to cognitive decline, given that hearing problems isolate people and reduce the cognitive stimulation available to them.  Regular hearing checks and using hearing aids when needed can help maintain brain health.⁶‍

3.    Untreated Vision Loss: Poor vision can reduce engagement in cognitive and social activities. Regular eye check-ups and addressing vision problems can help maintain overall brain health.⁷

4.    Smoking: Midlife smoking appears to be a stronger risk factor for dementia than smoking in late life.⁸ The sooner you quit tobacco, the better for your brain. Even reducing the number of cigarettes you smoke each day can help, though quitting entirely is the best thing to do for overall health.

5.    Obesity: Excess weight, especially around the midsection, increases inflammation and may adversely affect brain health.⁹ Consider implementing a balanced diet rich in fruits, vegetables, and whole grains, such as the MIND Diet. Likewise, recent evidence suggests that minimizing the consumption of soda and other “ultra-processed” foods protects the brain from cognitive decline.

6.    Depression: Depression at any age may increase the risk of dementia, with evidence suggesting a bidirectional relationship.¹⁰ Seeking help through talk therapy, medication, or lifestyle changes is important for both mental and cognitive health. 

7.    Physical Inactivity: Regular exercise improves blood flow to the brain and promotes the growth of new brain cells.¹¹ Finding activities you enjoy will facilitate staying active.

8.    Diabetes: Poorly controlled blood sugar can damage blood vessels in the brain, so much so that some researchers conceive of Alzheimer’s disease as “type 3 diabetes.” Working with a primary care clinician to manage diabetes or diabetes risk through diet, exercise, and medication is crucial for brain health.¹²

9.    Hypertension: High blood pressure, especially in midlife, increases the risk of cognitive decline and dementia.¹³ Regular monitoring and blood pressure management through diet, exercise, and, if necessary, medication are good for the body and the brain alike. ‍

10.    High LDL Cholesterol: This 'bad' cholesterol contributes to the buildup of atherosclerotic plaques in brain arteries. Diet, exercise, and sometimes medication can help control cholesterol levels.¹⁴‍

11.    Excessive Alcohol Consumption: Heavy drinking can damage brain cells. If you drink, try to keep it to no more than one drink a day for women or two for men.¹⁵ Abstinence is a fine, brain-protective choice. In early 2023, the World Health Organization stated that no amount of alcohol consumption is “safe.” 

12.    Social Isolation: Infrequent social contact is linked to higher dementia risk. Maintaining regular social interactions stimulates the brain and provides emotional support.¹⁶

13.    Air Pollution: Long-term exposure to air pollution can affect brain health. When possible, avoid high-traffic areas and use air purifiers indoors.¹⁷‍

14.    Traumatic Brain Injury (TBI): Protect your head by wearing seatbelts, using helmets in sports, and fall-proofing your home. Even mild concussions can have long-term effects.  ¹⁸

The Bottom Line

While we cannot control every risk factor for cognitive decline, there is still much we can do to maintain a healthy brain. It's never too early or too late to prioritize cognitive health. Keep in mind, many of the strategies we've discussed not only support brain health but also enhance overall well-being.

If you have concerns about your cognitive health, this is not the time to go it alone. Talk to your healthcare practitioner about your specific risk factors and the best strategies for you. With the right knowledge and a few smart moves, you can give your brain its best shot at staying sharp for years to come.

References:

1.    Alzheimer's Association. (2023). 2023 Alzheimer's Disease Facts and Figures. Alzheimer's & Dementia, 19(4), 1598-1695.

2.    Belloy, M. E., et al. (2019). A Quarter Century of APOE and Alzheimer's Disease: Progress to Date and the Path Forward. Neuron, 101(5), 820-838.

3.    Cannon-Albright, L. A., et al. (2019). A Population-Based Analysis of Familial and Sporadic Alzheimer's Disease. Alzheimer's & Dementia, 15(8), 1008-1015.

4.    Podcasy, J. L., & Epperson, C. N. (2016). Considering sex and gender in Alzheimer disease and other dementias. Dialogues in Clinical Neuroscience, 18(4), 437-446.

5.    Langa, K. M., & Larson, E. B. (2021). Education, Brain Health, and Improving Life Opportunities for Women. The Journal of the Economics of Ageing, 20, 100329.

6.     Yeo, B. S. Y., et al. (2023). Association of Hearing Aids and Cochlear Implants With Cognitive Decline and Dementia: A Systematic Review and Meta-analysis. JAMA Neurology, 80(2), 134-141.

7.     Shang, X., et al. (2021). The Association Between Vision Impairment and Incidence of Dementia and Cognitive Impairment: A Systematic Review and Meta-analysis. Ophthalmology, 128(8), 1135-1149.

8.     Hwang, P. H., et al. (2023). Examination of Potentially Modifiable Dementia Risk Factors Across the Adult Life Course: The Framingham Heart Study. Alzheimer's & Dementia, 19(8), 2975-2983.

9.     Qu, Y., et al. (2020). Association of body mass index with risk of cognitive impairment and dementia: A systematic review and meta-analysis of prospective studies. Neuroscience & Biobehavioral Reviews, 115, 189-198.

10.     Elser, H., et al. (2023). Association of Early-, Middle-, and Late-Life Depression With Incident Dementia in a Danish Cohort. JAMA Neurology, 80(9), 949-958.

11.     Iso-Markku, P., et al. (2022). Physical activity as a protective factor for dementia and Alzheimer's disease: systematic review, meta-analysis and quality assessment of cohort and case-control studies. British Journal of Sports Medicine, 56(12), 701-709.

12.     Barbiellini Amidei, C., et al. (2021). Association Between Age at Diabetes Onset and Subsequent Risk of Dementia. JAMA, 325(16), 1640-1649.

13.     Peters, R., et al. (2022). Blood pressure lowering and prevention of dementia: an individual patient data meta-analysis. European Heart Journal, 43(50), 4980-4990.

14.     Wee, J., et al. (2023). The relationship between midlife dyslipidemia and lifetime incidence of dementia: a systematic review and meta-analysis of cohort studies. Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring, 15(1), e12395.

15.     Mewton, L., et al. (2023). The relationship between alcohol use and dementia in adults aged more than 60 years: a combined analysis of prospective, individual-participant data from 15 international studies. Addiction, 118(3), 412-424.

16.     Sommerlad, A., et al. (2023). Social participation and risk of developing dementia. Nature Aging, 3, 532-545.

17.     Abolhasani, E., et al. (2023). Air pollution and incidence of dementia: a systematic review and meta-analysis. Neurology, 100(3), e242-e254.

18.     Gardner, R. C., et al. (2023). Systematic Review, Meta-Analysis, and Population Attributable Risk of Dementia Associated with Traumatic Brain Injury in Civilians and Veterans. Journal of Neurotrauma, 40(3-4), 620-634.