People aged 65 and over who suffer from hypothyroidism – which is characterized by a malfunction of the thyroid gland as a result of which it produces too little thyroid hormone – could have an increased risk of dementia, especially if they are following a thyroid hormone replacement therapy, reveals a new study published in Neurology.
The research authors analyzed the medical records of 7,843 adults with a mean age of 75 who had just been diagnosed with dementia and another 7,843 adults without this diagnosis who acted as controls, and in whom they evaluated their history of thyroid problems, both hypothyroidism –which causes symptoms such as tiredness, weight gain and excessive sensitivity to cold–, and hyperthyroidism, a condition in which, on the contrary, too many thyroid hormones are produced and whose main symptoms are nervousness, weight loss, hyperactivity concentration difficulties…
Correct thyroid function to prevent other diseases
After adjusting for aspects that could influence the risk of dementia such as sex, age, hypertension or diabetes, they found that a history of hypothyroidism was associated with an 81% higher risk of suffering from this mental illness. Among the participants, 235 had thyroid disease. Of these, 102 had hypothyroidism, and 133 hyperthyroidism. Of the people with dementia, 68 – 0.9% – had hypothyroidism, compared to 34 of the people without dementia, or 0.4%. They found no significant link between hyperthyroidism and dementia.
The study was observational “and therefore does not prove that hypothyroidism ’causes’ dementia, only that there is an association”
They also found that patients with hypothyroidism who took medication to correct this problem were more than three times as likely to develop dementia compared to those who were not on medication. According to Dr. Chien-Hsiang Weng, a clinical assistant professor at Brown University Warren Alpert School of Medicine in Providence, Rhode Island and lead author of the paper, this could be because “these patients had a more severe thyroid disorder and were more likely to experience symptoms of hypothyroidism that needed treatment, but which “are unlikely to be related to [los efectos secundarios del] medication itself.
Speaking to Medscape Medical News, Dr Weng said, “Thyroid function tests should be considered for patients with memory impairment or dementia problems.” “It is important to identify patients with thyroid disorders and correct their thyroid function as early as possible to help reduce the risk of several medical conditions, including dementia.”
Although the study has been carried out with people living in Taiwan, this scientist has pointed out that “the biological and molecular pathways behind this association are similar between ethnicities / races, the findings of our large-scale study offer solid evidence to the literature and possibly they can be generalized to non-Asian people.” But he also cautioned that the study was observational “and therefore does not prove that hypothyroidism ’causes’ dementia, only that there is an association.”
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