High levels of free T3 — a type of thyroid hormone — are associated with a lower rate of Alzheimer’s disease risk in patients who have subjective or objective mild cognitive impairment. Patients in the lowest quartile of free T3 levels had a twofold increase in the risk of developing Alzheimer’s compared to those in the highest quartile. These associations remained significant even after adjusting for multiple confounding variables.
In a press release, the authors suggest that monitoring of serum free T3 could be of value for patients who seek help for cognitive complaints. They went on to recommend that supplementation with thyroid hormones could be of use in patients who are likely to develop Alzheimer’s disease but have not yet presented symptoms. This concurs with Dr. Bredesen’s approach in optimizing thyroid hormones which act as important trophic factors for the brain.
Abstract
BACKGROUND:
In epidemiological studies, thyroid hormones (THs) have been associated with the risk of dementia. However, little is known of the relation between THs and risk of Alzheimer's disease (AD) or vascular dementia (VaD) in a memory clinic population.
METHODS:
In a mono-center study, serum concentrations of thyroid-stimulating hormone (TSH), free thyroxine (FT4), and free triiodothyronine (FT3) were assessed in 302 patients. All patients had subjective or objective mild cognitive impairment and none received treatment with THs. Cox proportional hazards regression analyses was used to determine whether THs at baseline were associated with the risk of conversion to all-cause dementia, AD or VaD.
RESULTS:
During the follow-up (mean 2.8 years), 82 (28%) of the patients progressed to dementia [AD, n = 55 (18%) and VaD, n = 17 (6%)]. Serum concentrations of TSH, FT4, and FT3 did not associate with all-cause dementia or VaD. Higher serum FT3 was associated with lower risk of conversion to AD [hazard ratio (HR) = 054; 95% confidence interval (CI): 0.32-0.92 per 1 pmol/L increase]. Furthermore, patients in the lowest serum FT3 quartile had a twofold increased risk of AD compared to those in the highest quartile (HR = 2.63; 95% CI: 1.06-6.47). These associations remained after adjustment for multiple covariates.
CONCLUSIONS:
In a memory clinic population, there was an inverse, linear association between serum FT3 and risk of AD whereas THs did not associate with all-cause dementia or VaD. Further studies are needed to determine the underlying mechanisms as well as the clinical significance of these findings.
I've been on thyroid hormones since 1990. For at least the past 8 years, my free T3 has been in the lowest quartile of free T3 no matter what my medication dosage is (or which thyroid medication I'm using). It's very frustrating. Dr. Ackerley, with whom I had a consultation about my NeuroQuant results, said that my atrophied hypothalamus might be to blame. Unforunately, she didn't know what I could do to improve this problem.
ApoE 4/4 - When I was in 7th grade, my fellow students in history class called me "The Brain" because I had such a memory for detail. I excelled at memorization and aced tests. This childhood memory helps me cope!
Thank you Julie, for posting about this study. This information is very helpful to me, and I would not have known about it otherwise. I'm sending the link to my doctor and will be discussing at my next visit. I feel very grateful to you and to everyone who comprises this group, and that I can be a part of it!
I just say from personal experience that when my thyroid meds have been off it has impacted my cognition greatly. I feel it is definitely one of those 36 holes!
