Women's Thyroid Levels Linked to Risk of Alzheimer's Disease
Women with low or high levels of the hormone thyrotropin (also known as Thyroid Stimulating Hormone, or TSH) have an increased risk of Alzheimer's disease. The findings were reported in the July 28 issue of the Archives of Internal Medicine.In this large study, which was part of the community-based Framingham Study, almost 2,000 patients were periodically evaluated for dementia over more than a decade.
Over almost 13 years of follow ups, 209 patients developed Alzheimer's disease. In women, TSH levels were significantly linked to Alzheimer's disease, and there was a greater than two-fold higher risk for the women with a TSH below 1.0 and those with levels above 2.1. (No relationship was seen in men.)The researchers do not know whether the thyroid changes are occurring before or after the onset of Alzheimer's disease, or what the connection is, and recommend that further research be conducted to determine if there are any implications for treatment or prevention.Perhaps the most important finding, however, was that the results were the same, whether patients were taking thyroid medication or not.The operative factor appeared to be the TSH level.While measurable hyperthyroidism or hypothyroidism can cause cognitive problems, and difficulties with memory, thinking, and learning, it was usually considered to be reversible with proper thyroid treatment. This study challenges the traditional dogma that thyroid problems are a reversible cause of cognitive impairment, and instead, suggests that an imbalance in thyroid function may even be a contributory factor in Alzheimer's disease.