I have long suspected a link between my TSH levels and my cholesterol levels. WebMD states that " If you have thyroid disease, you're more prone to have high cholesterol levels. In fact, as many as 13% of people who have hypothyroidism will also have high levels of " bad" LDL cholesterol. Hypothyroidism is also linked with too high levels of triglycerides( blood fats that are associated with cholesterol). Both of these issues increase your risk for heart disease and stroke."
OK, here is my proof! Well, part of it. I was curious about cancer patients, like me, who had a total thyroidectomy and had to depend on thyroid hormone replacement. How do our TSH levels affect our cholesterol? I found a ground breaking study ( well, to me, anyway) about differentiated thyroid cancer ( this includes papillary and follicular and is abbreviated, DTC) and the association between TSH ( thyroid stimulating hormone) and high cholesterol levels. The name of the study is " Association between Thyroid Stimulating Hormone level after Total Thyroidectomy and Hypercholesterolemia in Female Patients with Differentiated Thyroid Cancer: A Retrospective Study." This study was published in the Journal of Clinical Medicine on 2019 Aug: 8(8): 1106 and is authored by: Young Ki Lee, Hokyou Lee, and others. The information that I will provide in this blog is from this study.
At first, physicians kept thyroid cancer patients' TSH completely suppressed- which means essentially zero. This was done so that hopefully no rogue thyroid cancer cells could be "awakened" and lead to spread- either in the neck bed or other places in the body. In patients where concerns over recurrence were fairly low, the general treatment protocols changed. Instead of keeping the TSH at near zero, it was decided ( who decides these things?) that it would be best to let the patient's TSH creep back up to within the normal range. This study found that these patients who achieved normal TSH levels after thyroidectomy, also had high cholesterol values. Fun fact: thyroid hormones help the liver process the cholesterol in the blood stream. If thyroid hormone levels are low, the blood is processed less efficiently, so the cholesterol can increase. If there is anyone out there who does not know this already, high cholesterol can cause heart disease and stroke for starters.
One of the biggest take aways ( at least for me) from the article cited above was that " normal " TSH levels could lead to high cholesterol due to insufficient replacement of thyroid medication. In other words, normal TSH levels are not an indicator by themselves as to what would be a correct thyroid replacement dose. It is important to look at serum cholesterol levels as an additional marker in the determination of a proper thyroid hormone dose. The study also mentioned the fact that a patient with "normal" TSH values could actually be hypothyroid due to T3 deficiency. More on this fact at the exciting conclusion of this blog!
So, we have learned that the higher the TSH, the more likely the patient is to have higher total cholesterol or LDL cholesterol. At this point, you may be wondering about exact blood values for TSH. What is considered " normal", high, low, or optimal. When one has blood work done, there are slight variations in the level- from lab to lab. I am citing the values that were used in this study. Obviously, there will be some variation, but this is a pretty tight range.
TSH values from 0.3-2.0 mIU/L were associated with 1.86 to 5.08 times higher odds for having high cholesterol. This was considered a moderate or normal level in this study.
TSH values from 2.0-5.0 mIU/L were associated with 2.85 to 6.95 times higher odds for having high cholesterol. This was considered a high TSH in this study.
TSH levels of less than 0.02mIU/L in patients were associated with higher cardiovascular mortality values. This was considered a low TSH in this study.
Basically, too low is potentially harmful as is too high when looking at TSH values. Where is the sweet spot? According to this study it is, drum roll please:
A mildly suppressed TSH level of 0.03-0.3 mIU/L may be the optimal value ( aka, sweet spot) to have to minimize cardiovascular events and keep that darn cholesterol down where it should be!
I am seeing a new endocrinologist next week. ( Side note: yes, I am still searching for that special endocrinologist who is a good fit for me. I have yet to find a physician like my old endocrinologist who retired a few years ago ) .I am going to take this study with me and talk with my new physician about it. My previous endocrinologist ( not my retired one) lowered the dose of my levoxyl and I do not feel well! My T3 is down, while my T4 is within normal range. My TSH , measured a month or so ago, was 0.8. I feel that it is higher now as I am having hypothyroid symptoms. I do not need to explain what these are to any thyroid cancer patient!
After reading this study, I would like for my lab results to be in the above mentioned " sweet spot" range. I have not had my cholesterol checked in a while, but I do know that in the not so distant past, my cholesterol was creeping up. It was higher than it had been before I had my thyroidectomy. The hypothyroid symptoms that I have been experiencing are impacting the quality of my life. And I certainly do not want my cholesterol to get out of control! Hopefully, studies like this may help more physicians to realize that there is a optimal range or sweet spot for TSH so as to prevent recurrence, being able to keep cholesterol at a healthy level, and enabling the patient to feel as " normal" as possible. I am hoping that there will be some juggling or dose adjustments of my thyroid dose coming up. There will probably be more blood work, but I am willing to undertake this. I just need to find an endocrinologist who is willing to take that journey with me.
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