Thyroid Problems Linked to Increased Risk of Developing Dementia

Thyroid Patient Concept

According to new research, older people with hypothyroidism may be at increased risk of developing dementia.

Older people with underactive thyroid, which is formally called hypothyroidism, may be at increased risk of developing dementia, according to a new research study published in the July 6, 2022, online issue of Neurology, the medical journal of the American Academy of Neurology. According to the findings, the risk of developing dementia was even higher for people whose thyroid condition was serious enough to require thyroid hormone replacement medication.

Simply stated, hypothyroidism occurs when the thyroid gland doesn’t make enough thyroid hormones. This can slow metabolism. Symptoms include feeling tired, dry skin, weight gain, puffy face, and sensitivity to cold.

“In some cases, thyroid disorders have been associated with dementia symptoms that can be reversible with treatment,” said study author Chien-Hsiang Weng, MD, MPH, of Brown University in Providence, Rhode Island. “While more studies are needed to confirm these findings, people should be aware of thyroid problems as a possible risk factor for dementia and therapies that could prevent or slow irreversible cognitive decline.”

For the study, scientists analyzed the health records of 7,843 people newly diagnosed with dementia in Taiwan and compared them to the same number of people who did not have dementia. The average age of study participants was 75. Researchers examined the data to see who had a history of either hypothyroidism or hyperthyroidism. Hyperthyroidism, which is also called overactive thyroid, is when the thyroid produces too much hormone. This can increase metabolism. Symptoms include unintended weight loss, rapid or irregular heartbeat, and nervousness or anxiety.

The prefixes hypo- and hyper- are opposites. Hypo means low, under, down, or below normal. Hyper means high, over, up, or above normal.

A total of 102 people had hypothyroidism and 133 had hyperthyroidism.

The researchers found no link between hyperthyroidism and dementia.

Of the people with dementia, 68 people, or 0.9%, had hypothyroidism, compared to 34 of the people without dementia, or 0.4%. When researchers adjusted for other factors that could affect the risk of dementia, such as sex, age, high blood pressure, and diabetes, they found that people over age 65 with hypothyroidism were 80% more likely to develop dementia than people the same age who did not have thyroid problems. For people younger than 65, having a history of hypothyroidism was not associated with an increased risk of dementia.

When researchers looked only at people who took medication for hypothyroidism, they found they were three times more likely to develop dementia than those who did not take medication. “One explanation for this could be that these people are more likely to experience greater symptoms from hypothyroidism where treatment was needed,” Weng said.

Weng noted that the observational study does not prove that hypothyroidism is a cause of dementia; it only shows an association.

A limitation of the study was that researchers were not able to include information about how severe the hypothyroidism was for participants.

Reference: “Thyroid Disorders and Dementia Risk: A Nationwide Population-Based Case-Control Study” by Daniel R Wieland, Julia R Wieland, Han Wang, Yi-Huei Chen, Ching-Heng Lin, Jing-Jie Wang and Chien-Hsiang Weng, 6 July 2022, Neurology.
DOI: 10.1212/WNL.0000000000200740

5 Comments on "Thyroid Problems Linked to Increased Risk of Developing Dementia"

  1. Charles G. Shaver | July 8, 2022 at 10:16 am | Reply

    Article after article, chronic health problem after chronic health problem, beginning with the US FDA in October of 2005 about allergies, added ‘cultured’ MSG, chronic disease and obesity (obviously, now in-vain) I’ve been writing on them for sixteen years and counting (updating as possible). I know from my own adult chronic illness experience that short term memory loss can be allergy, food additive and resultant nutritional deficiency (e.g. calcium; standard blood testing being unreliable) related and at least partial recovery is possible. One of my older online lay findings was that both added MSG (since 1980) and soy (since the late 1960s) were known to harm the thyroid in lab mice and rats. More recently I found that added MSG can cause a vitamin B6 deficiency and soy can interfere with the uptake of thyroid hormone, even synthroid. Clearly, to me, undiagnosed allergies, MSG and soy can account for a lot of American dementia and, perhaps, the same is true in Asia now as they adopt the ‘Western Diet’ and fall prey to many of the same chronic disease conditions the US became a self-destructive global leader in decades ago, as added MSG and soy became ubiquitous to products of the US commercial pseduo-food industry.

    • Consumption of both MSG and soy is far higher in Asian populations than in the west. So your theory doesn’t hold up.

      • Charles G. Shaver | July 9, 2022 at 5:35 am | Reply

        Thanks for the input Daniel D. Relying only on aging recollection and the article above, I recall reading long ago it’s a myth that Asians ingest a lot more MSG and Soy than Americans. In their native diet they consume a lot of fish and rice and what soy they ingest, perhaps ten percent of their diet, tops, is fermented beyond tofu and miso. Even soy sauce is fermented, altering the ‘free’ MSG. Furthermore, without knowing how prevalent chronic subclinical non-IgE-mediated food allergies are in Asia (or in the US; a supreme failure of mainstream medicine) and factoring that in, even the most diligent of medical research is guess work, at best, evidenced best with global increases in epidemic chronic diseases.

  2. It’s wheat/ gluten. The unnaturally created stickiness is one association, besides the inflammation it causes, there is a bacteria that mimics the gluten molecule. Your body thinks your eating pounds of bacteria, and acts accordingly. Gluten also prohibits absorbsion of nutrients. Destroys the hairs in your intestines. Soy, when not fermented, also causes many of the same things. Not enough room here to explain it properly.

    • Charles G. Shaver | July 11, 2022 at 9:17 am | Reply

      Hello Roger. Thanks for the intellectual stimulation. Apparently not bothered by gluten and never even tested, myself, a cursory look at a few articles on the prevalence of celiac disease (CD) suggest it too has increased exponentially in the US since 1980. And, that is consistent with my own experience that added ‘cultured free’ MSG aggravated my multiple subclinical non-IgE-mediated (failed skin-prick testing in 1973) food allergies to become chronic disease producing. Not a healthcare professional myself, it now suggests to me if you have CD and eliminate added MSG and soy (e.g. most commercially prepared ‘pseudo-meats’) from your diet you may be better able to tolerate gluten.

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