We keep hearing of doctors who deny that cholesterol levels are linked to hypothyroidism. The comments on forum often say something like “they used to use cholesterol as an indicator of thyroid levels”. However, rarely has this actually been complemented by a link, a quote, of an actual example.

I found this case report, one of nine in the paper, when I was looking for something else. It was published in the British Medical Journal in 1950.

In addition to the specific cholesterol issue, some may find interest in what was happening around the time thyroxine started to become available.

ORAL THYROXINE IN TREATMENT OF
MYXOEDEMA
BY
F. DUDLEY HART, M.D., F.R.C.P.
Assistant Physician, Westminster Hospital; Lecturer in
Applied Pharmacology, Westminster Medical School
AND
N. F. MACLAGAN, D.Sc., M.D., M.R.C.P.
Professor of Chemical Pathology in University of London
at Westminster Medical School; Chemical Pathologist to
Westminster Hospital

Case 2 (See Fig. 2)

A married woman aged 63 was diagnosed as a case of myxoedema in 1936, and treated with dried thyroid extract.

1946, after ten years' treatment, she ceased to attend. After eighteen months there was a gradual return of symptoms.

On examination typical myxoedema was noted. Her blood pressure was 170/100. Renal function was 64% of normal.

The initial B.M.R. was -21%, and serum cholesterol 437 mg. per 100 ml.

Treatment.-

DL-thyroxine 1 mg. daily was given. Within a week she began to feel better and lost weight. In a fortnight her voice had almost returned to normal. Serum cholesterol dropped to 205 mg., and urea clearance rose to 81% of normal.

Improvement was in every way satisfactory. Thyroxine was increased to 1.4 mg. a day. Her only disability was that the hair continued to fall out. Her energy was still slightly sub-
normal. Thyroxine was increased to 1.8 mg. a day. One month later she stated that she had stopped "falling about” and was now entirely steady on her feet, although her gait had always been unsteady since the onset of myxoedema. Her hair was now falling out much less. Treatment was changed to DL-sodium thyroxine 1 mg. a day, then reduced to 0.6 mg. after two months. Two months later treatment was changed to L-sodium thyroxine (0.3 mg. a day).

Comment.-

Improvement was entirely satisfactory when on 1 mg. of DL-thyroxine sodium. Her B.M.R. rose to +22% and serum cholesterol dropped to 206 mg. On the reduced dosage she continues to be well. She appears to be at her best when [u]the cholesterol reading is slightly raised[/u] and the B.M.R. is within the normal range. The only time the cholesterol figure has been within normal limits was when other symptoms suggested that dosage was excessive. She has been on L-thyroxine sodium for four months. Her present dose is 0.2 mg. a day. The observation period was one year five months.

https://europepmc.org/backend/ptpmcrender.fcgi?accid=PMC2037331&blobtype=pdf

Explanatory notes:

B.M.R. - Basal Metabolic Rate 

DL-thyroxine-sodium - a mixture of L-thyroxine (which we widely call levothyroxine) and D-thyroxine which is no longer used. D-thyroxine is not the form found in our bodies. It required much higher doses and was eventually recognised as causing heart issues. Which is why we now only see L-thyroxine. It also partly the doses quoted appearing much higher than we see today. It is also possible that the less exacting purity of the product, and issues about how it was delivered, also affected requirements.

Application of Thyroid Hormones in Women's Hair for the Non-Invasive Prediction of Graves' Disease

An interesting development in the realm of FT4 and FT3 testing.

Application of Thyroid Hormones in Women's Hair for the Non-Invasive Prediction of Graves' Disease
Kouhei Igarashi  1   2 , Chie Takita  1   2 , Masako Matsumoto  3 , Wataru Kitagawa  4 , Atsuko Ota  2 , Naoko Miyazaki  5 , Koichi Ito  4 , Kazutaka Ikeda  1   6
Affiliations

    PMID: 40149889 DOI: 10.3390/biom15030353

Abstract

Graves' disease (GD) is an autoimmune disorder that can be difficult to distinguish from other diseases due to symptom similarity. The exacerbation of GD owing to delayed diagnosis is a serious issue, and a novel accessible health screening system is needed. Therefore, this study investigated the association between GD and thyroid hormone levels in women's hair and evaluated the prediction accuracy of this non-invasive type of sample. By optimizing pretreatment and analysis techniques using liquid chromatography-mass spectrometry (LC-MS), free triiodothyronine (FT3) and thyroxine (FT4) could be detected in only 2 mg of hair with high sensitivity. Compared with healthy controls, the thyroid hormone levels in the hair of GD patients were significantly higher in correlation with blood levels. The predictive ability of hair thyroid hormones was analyzed using a receiver operating characteristic (ROC) curve, and the optimal cut-off value was determined via the Youden index. As a result, the area under the curve (AUC) was 0.974 (95% confidence interval (CI): 0.935-1.000) for FT3 and 0.900 (95% CI: 0.807-0.993) for FT4. The cut-off value was 0.133 pg/mg (sensitivity: 91.2%; specificity: 100%; positive predictive value (PPV): 100%; negative predictive value (NPV): 76.9%) for FT3 and 0.067 pg/mg (sensitivity: 70.6%; specificity: 100%; PPV: 100%; NPV: 50.0%) for FT4. Collectively, our new approach offers the possibility of accurately and non-invasively detecting GD using hair samples. Since hair can be stored and transported at room temperature, this system facilitates large-scale screening at locations including hair salons and homes, potentially enabling the early determination of GD outside of medical facilities.

Keywords: Graves’ disease; health check; lipidomics; mass spectrometry; non-invasive hair screening; thyroid hormone.

Igarashi, K., Takita, C., Matsumoto, M., Kitagawa, W., Ota, A., Miyazaki, N., Ito, K., & Ikeda, K. (2025). Application of Thyroid Hormones in Women's Hair for the Non-Invasive Prediction of Graves' Disease. Biomolecules, 15(3), 353. https://doi.org/10.3390/biom15030353

https://pubmed.ncbi.nlm.nih.gov/40149889/

29/03/2025

Thyroid Hormones and Metabolism Regulation: Which Role on Brown Adipose Tissue and Browning Process?

We have two types of adipose tissue (fat cells) - white and brown.

White adipose tissue is primarily fat storage.

Brown adipose tissue is capable of generating heat directly by metabolic processes. Not by shivering. Not by any muscle actions.

White fat cells, adipocytes, can convert to brown adipocytes. 

This conversion is controlled, at least in part, by thyroid hormones.

(You might occasionally see discussion of beige adipocytes.)

Thyroid Hormones and Metabolism Regulation: Which Role on Brown Adipose Tissue and Browning Process?
Laura Sabatino  1 , Cristina Vassalle  2
Affiliations

    PMID: 40149897 DOI: 10.3390/biom15030361

Abstract

Thyroid hormones (THs) are important modulators of many metabolic processes, being strictly associated with the control of energy balance, mainly through activities on the brain, white and brown adipose tissue, skeletal muscle, liver, and pancreas. In this review, the principal mechanisms of TH regulation on metabolic processes will be discussed and THs' relevance in metabolic disease progression will be evaluated, especially in the cardiovascular context and correlated diseases. Moreover, we will discuss THs' regulatory role on metabolic events in white and brown adipose tissue, with a special focus on the process of "browning", which consists of the gradual acquisition by white adipocytes of the physical and functional characteristics of brown adipocytes. The advancements in research on molecular mechanisms and proposed physiopathological relevance of this process will be discussed.

Keywords: brown adipose tissue; browning; metabolism; thyroid hormones.

Sabatino, L., & Vassalle, C. (2025). Thyroid Hormones and Metabolism Regulation: Which Role on Brown Adipose Tissue and Browning Process? Biomolecules, 15(3), 361. https://doi.org/10.3390/biom15030361

https://www.mdpi.com/2218-273X/15/3/361

29/03/2025

helvella - Fasting for blood tests

My view is this: Always fast for blood tests.

My logic is this:

For most tests, most of the time, fasting might make no difference. Sometimes fasting might make a modest difference. But there are some tests which must be done fasting.

Say we don’t usually fast. Then we are scheduled to have a test which definitely requires fasting.

If that is the only test we are having, fine.

If we have that test in combination with other tests, ones which do not need fasting, this time they are done in a fasting state. Though previously the same tests might have been done without fasting.

Any effects due to fasting (or not), even if small, make comparison with previous tests just a bit more questionable. Was that a real and potentially important difference? Or was it due solely to fasting?

Always fast and the question disappears.