Individuals with PCOS are at an increased risk of developing Alzheimer’s Disease[1],[2] and up to 2x the risk of developing any form of dementia.[3] In this article we explore the link between PCOS and Alzheimer’s Disease.
Alzheimer's disease (AD) is the most common form of dementia, accounting for 60-80% of all cases.[4] AD is caused by the formation of two abnormal structures in the brain, beta-amyloid plaques between nerve cells and tau protein tangles within cells.[5]
Dementia is associated with loss of memory, language, problem-solving and other cognitive abilities beyond what is associated with normal aging.[6],[7]
Individuals with PCOS have been found to have increased lesions on the white matter of the brain, the network of nerve fibers that allows the exchange of information, and cerebral infarcts, related to disrupted blood flow to the brain.[8] In addition, individuals with PCOS show reduced diffusion or transport of neuroactive substances such as hormones along the main axis of white matter fibers.[9],[10]
PCOS is believed to be linked to cognitive function and dementia through a number of potential mechanisms:[11]
Hormonal disruptions, including elevated androgens and lower estrogen and progesterone;
Metabolic changes and health complications, including insulin resistance, diabetes and obesity; and
Increased prevalence of sleep disorders, such as obstructive sleep apnea (OSA).
PCOS is associated with elevated levels of androgens[12], sex hormones that are produced in the ovaries, start at puberty and play a key role in reproductive health.[13] Learn more about PCOS and Androgen Excess.
High androgen levels stimulate the production of amyloid -beta (Aβ), a large protein involved in synaptic plasticity and learning;[14]
Increased production of Aβ leads to its accumulation within the brain;[15]
In Alzheimer’s these Aβ proteins clump together and form plaques;[16]
As above, these plaques cause damage to nerve cells and result in reduced executive function, the set of skills you use to manage every day such as making plans, solving problems and adapting to new situations.[17]
Interestingly, age-related loss in testosterone is associated with increasing risk of AD in men.[18] High circulating androgens in individuals with PCOS are conversely associated with improved verbal psychometer speed,[19] the rate at which you process verbal information.
PCOS can be associated with elevated insulin resistance, where your body produces insulin but it cannot use the insulin effectively to balance your blood sugar.[20] Find out more about PCOS and Insulin Resistance.
In individuals with PCOS, increased insulin resistance has been shown to be correlated with an increased prevalence of AD.[21] Our brain accounts for only c. 2% of our body weight but consumes c. 20% of glucose-derived energy.[22] Individuals with PCOS were shown to have 9-14% lower metabolic rate in the frontal, parietal and temporal cortices of the brain than individuals without the condition.[23]
Risk factors for AD include:[24],[25]
Increasing age;
Genetics/family history of AD;
Having Down’s Syndrome;
Mild cognitive impairment, with one study finding that 40% of those over 65 with mild cognitive impairment developed dementia within 3 years;
Having had a traumatic brain injury (TBI), particularly athletes who experience repeated head injuries or older adults who experience falls;
Atherosclerosis, the buildup plaque, made up of fats, cholesterol and other substances, on the walls of your arteries;[26]
Hypertension, or high blood pressure;
Diabetes, particularly for those who develop Type 2 Diabetes in mid-life;[27]
Obesity in mid-life, also correlated with other risk factors such as hypertension and diabetes;
High cholesterol, a waxy substance food in your blood;[28]
Having depression in mid- or later life;
Hearing loss, leading to social isolation and lack of independence;
Social isolation, also correlated with other risk factors such as hypertension and depression;
Physical inactivity, particularly in later life;
Vitamin D deficiency;[29]
Use of tobacco; and
Binge drinking, patterns of drinking alcohol that result in a blood alcohol concentration (BAC) of 0.08% or more, equivalent to a women drinking 4 of more drinks in 2 hours or less[30] (moderate drinking has been shown in some studies to reduce dementia risk).
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Reviewed by Dr. F, one of Neuraura’s friends and trusted advisors.
Sources
[1] https://pmc.ncbi.nlm.nih.gov/articles/PMC10816448/
[2] https://www.sciencedirect.com/science/article/pii/S2589790X23003785
[3] https://www.sciencedirect.com/science/article/pii/S2589790X23003785
[4] https://www.alz.org/alzheimers-dementia/what-is-alzheimers
[5] https://www.alz.org/alzheimers-dementia/what-is-alzheimers
[6] https://www.alz.org/alzheimers-dementia/what-is-dementia
[7] https://www.who.int/news-room/fact-sheets/detail/dementia
[8] chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://www.ogscience.org/upload/pdf/ogs-22165.pdf
[9] chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://www.ogscience.org/upload/pdf/ogs-22165.pdf
[10] https://www.sciencedirect.com/science/article/pii/S0969996122003734
[11] chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://www.ogscience.org/upload/pdf/ogs-22165.pdf
[12] https://www.uptodate.com/contents/polycystic-ovary-syndrome-pcos-beyond-the-basics/
[13] https://my.clevelandclinic.org/health/articles/22002-androgens
[14] https://www.sciencedirect.com/topics/medicine-and-dentistry/amyloid-beta
[15] chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://www.ogscience.org/upload/pdf/ogs-22165.pdf
[16] https://www.nia.nih.gov/health/alzheimers-causes-and-risk-factors/what-happens-brain-alzheimers-disease
[17] https://my.clevelandclinic.org/health/articles/executive-function
[18] https://academic.oup.com/endo/article/159/12/3885/5094961
[19] chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://www.ogscience.org/upload/pdf/ogs-22165.pdf
[20] https://www.cdc.gov/diabetes/risk-factors/pcos-polycystic-ovary-syndrome.html
[21] chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://www.ogscience.org/upload/pdf/ogs-22165.pdf
[22] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3900881/
[23] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4674147/
[24] https://www.alz.org/alzheimers-dementia/what-is-alzheimers/causes-and-risk-factors
[25] https://alzheimer.ca/en/about-dementia/how-can-i-reduce-risk-dementia/risk-factors-dementia
[26] https://www.mayoclinic.org/diseases-conditions/arteriosclerosis-atherosclerosis/symptoms-causes/syc-20350569
[27] https://www.healio.com/news/primary-care/20230530/top-in-endocrinology-early-diabetes-and-dementia-risk-pcos-body-image-study
[28] https://www.mayoclinic.org/diseases-conditions/high-blood-cholesterol/symptoms-causes/syc-20350800
[29] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8314638/
[30] https://www.niaaa.nih.gov/publications/brochures-and-fact-sheets/binge-drinking
Complications - Neurological