why do endocrinologists not like the TSH levels to be low?

[Schenks]

Does anyone know what the implications are? My endo last time was banging on about the levels being too low (less than 0.03) and i felt rather hammered - although he is a nice guy and supportive and listens.

[shaws Administrator]

Some believe you will either have a heart attack or a osteoporosis.

web.archive.org/web/2010122...

web.archive.org/web/2010122...

Dr Toft ex President of the BTA and RCOP has said in his article in Pulse that some need to have a suppressive dose to be well.

Dr Lowe and research has shown that is what we need. Excerpts

“. . . in a study of patients made hypothyroid by therapeutic destruction of the thyroid gland, some used TSH-suppressive doses of thyroid hormone and others used T4-replacement. Those on TSH-suppressive dosages did not gain excess weight; those on T4-replacement did. The researchers concluded that T4-replacement was the cause of the excess weight gain.[55]”

Unfortunately, even when many patients take a dose of T4 alone that's high enough to suppress their TSH levels, the treatment is not effective for some 50% of patients. It's well worth noting, though, that most patients lose their excess weight and recover their health when they switch to thyroid hormone products that contain both T4 and T3 or T3 alone and take doses high enough to lower their TSH levels. Many can't find doctors who'll cooperate by prescribing these superior products.

web.archive.org/web/2010112...

[NBob]

To back up what shaws said. There are pieced of research that show that low TSH does not cause atrial fibrillation (heart flutters) or osteoporosis. Here are some of them

1. It is safe for patients who take thyroxine to have a low (0.04 – 0.4 mU/l) but not suppressed (=0.03 mU/l) serum TSH concentration. There is no risk of atrial fibrillation or osteoporosis at the low TSH level.

Is it safe for patients taking thyroxine to have a low but not suppressed serum TSH concentration? Graham Leese & Robert Flynn University of Dundee Endocrine Abstracts (2010) 21 OC5.6

2. “The aim of thyroid replacement therapy is to achieve a euthyroid state. This should be determined by the signs and symptoms of the patient rather than solely on the position of the pituitary hormone TSH in the disputed reference range.

In a large study of patients with new-onset AF, less than 1% of AF incidence was caused by overt hyperthyroidism. Therefore, although serum thyroid-stimulating hormone (TSH) is measured in all patients with new onset AF to rule out thyroid disease, this association is uncommon in the absence of additional symptoms and signs of hyperthyroidism”.

"How useful is thyroid function testing in patients with recent-onset atrial fibrillation? Krahn AD, Klein GJ, Kerr CR, Boone J, Sheldon R, Green M, Talajic M, Wang X, Connolly S. Source University of Western Ontario, London. Arch Intern Med 1996, 156:2221-2224."

3. Abnormalities of heart morphology associated with impaired exercise performance occur as a consequence of long term therapy with fixed TSH-suppressive doses of L-T4, but these abnormalities improve or disappear after careful tailoring of TSH-suppressive therapy.

Cardiac Function, Physical Exercise Capacity, and Quality of Life during Long-Term Thyrotropin- Suppressive Therapy with Levothyroxine: Effect of Individual Dose Tailoring Giuseppe Mercuro, Maria Grazia Panzuto, Alessandro Bina, Maria Leo, Rosanna Cabula, Laura Petrini, Francesca Pigliaru, And Stefano Mariotti Institute of Cardiology (G.M., M.G.P., A.B., M.L.) and Endocrinology, Department of Medical Sciences (R.C., L.P., F.P., S.M.), University of Cagliari, 09124 Cagliari, Italy 2000

4. The benefits of treatment of mild thyroid failure with appropriate doses of L-thyroxine outweigh the risk.

Hypothyroidism as a Risk Factor for Cardiovascular Disease Bernadette Biondi and Irwin Klein Endocrine, vol. 24, no. 1, 1–13, June 2004

5. There are disjoints between FT4-TSH feedback and T3 production that persist even when sufficient T4 apparently restores euthyroidism. T4 treatment displays a compensatory adaptation, but does not completely re-enact normal euthyroid physiology.

Is Pituitary Thyrotropin an Adequate Measure Of Thyroid Hormone-Controlled Homeostasis During Thyroxine Treatment? Hoermann R, Midgley JE, Larisch R, Dietrich JW. Eur J Endocrinol. 2012 Nov 26. [Epub ahead of print] Source R Hoermann, Department of Nuclear Medicine, Klinikum Luedenscheid, Lüdenscheid, Germany.

6. There was little evidence of adverse LT(4) effects on bone; however, premenopausal women with DTC might be at risk for reduced vBMD in their ultradistal radii.

Effects of levothyroxine on bone mineral density, muscle force, and bone turnover markers: a cohort study.

Schneider R, Schneider M, Reiners C, Schneider P.

J Clin Endocrinol Metab. 2012 Nov;97(11):3926-34. doi: 10.1210/jc.2012-2570. Epub 2012 Sep 13.

[Schenks]

Gosh, thank you both. I don't understand most of it, but I'm going to try and fathom it all out so that I don't get the frighteners put on me by the endo again. i really appreciate the time and effort you have taken to show me the way to point my nose, very grateful indeed.

[shaws Administrator in reply to Schenks]

This is an excerpt from Thyroid Science:-

Oddly, based on the negative outcome of these studies, some endocrinologists advise that T -replacement should remain the treatment of choice for hypothyroid patients.Their advice, however, disregards two humanitarian imperatives:

(1) The endocrinology specialty must officially and publicly concede that many patients continue to suffer from hypothyroid symptoms despite their use of replacement therapies. This is especially important in view of other studies. The other studies suggest that for many patients, T4-replacement therapy increases the incidence of potentially fatal diseases and boosts chronic drug use to control the patients’ hypothyroid symptoms and those of the other diseases.

(2) These patients must have access to alternate thyroid hormone therapies, especially TSH-suppressive therapies, that are safe and effective for them.

These imperatives require that the endocrinology specialty now impartially consider approaches to thyroid hormone therapy other than replacement.

web.archive.org/web/2009020...

[Schenks]

Blimey - and thanks again for this. It's all a bit scary, i have to say. But you've taken such time for me - I don't really know how to thank you enough.

[zombiefan1]

My results today is showing surpressed 0.03