Thyroid UK
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Analysing the healthy TSH range by probability

I though people on here would be interested in a paper by Hammilton et al, J Clin Endocrinol Metab, April 2008, 93(4):1224–1230 which looked at a large healthy population to obtain a TSH range arranged in percentages at each 0.5 unit. The range overall was 0.5-4.5. Looking at percentages of subjects in particular 0.5 unit widths they found the following (rounding to nearest %): <0.5, 5%; 0.5-1.0, 25%; 1.0-1.5 28%; 1.5-2.0, 19%; 2.0-2.5, 10%; 2.5-3.0, 4%; 3.0-3.5, 3%; 3.5-4.0, 2%; 4.0-4.5, 1%. So looking at probabilities, only 10% of healthy people have TSH above 3 units. So if an individual presents to a doctor with that value there is only a 10% chance this is satisfactory for them. 72% of people lie between 1 and 2 units. this is why some doctors believe that TSH above 2.5 is not likely to be optimal for a presenting individual.

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This is really great information. I often look at results for friends, many of whom probably don't turn out to have a thyroid problem, and I wonder what the truly healthy range looks like.

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Very interesting diogenes thank you for sharing.

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That is very interesting.

I wish all doctors would believe that TSH above 2.5 is not likely to be optimal for a presenting individual. How to we get them to 'believe'?

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Thanks Diogenes, interesting info. I understand that you have to hit approx 10.0 in the UK before you get taken seriously as a thyroid patient. That is scandalous.

Do you have a link so that we can take this info to our docs, pls? If not that's OK I can Google it.

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Link is : academic.oup.com/jcem/artic...

If you want a PDF file of the paper there is a link to the PDF near the top of the page.

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Thank you very much hb.

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Wow, just read the paper. It was a bit difficult to understand, my statistics can manage a Gausian distribution but once you transfer onto a log scale I start to sputter. However, I am SO glad that there are real scientists, statisticians and people who know what they are talking about working on problems which affect us so directly.

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Did you notice the date on the paper though? It was published in 2008.

When I looked at the Google Scholar entry for the paper it said it had been cited 119 times which is good, but in practice I can't see that it has had any impact in "real life" as it is lived by thyroid patients. :(

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I looked at the list of papers citing the paper concerned, and I liked the look of this one :

sci-hub.io/10.1038/nrcardio...

Thyroid hormones and cardiovascular disease

It was published in Nature.

nature.com/nrcardio/journal...

I remember once being told by a cardiologist that T3 was bad for the heart. There is plenty of evidence to suggest that she was talking b******s. :)

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I get the impression cardiologists like it more than Endos do :p

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I must have been unlucky with my cardiologist then. I'm usually unlucky where doctors are concerned. :(

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Really interesting article thanks for sharing Diogenes - I and feel so grateful for this forum where we can share information and learn more about how inadequate our treatment can be. I am glad that I have access to this!

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I have only skimmed this article but note that they are not actually advocating an upper limit of 2.5. Quote: 'Based on these results, and our concern that an upper limit of 2.5 may result in inappropriate therapy of euthyroid individuals, we recommend an upper limit near 4.0 for the TSH reference range.'

So alas this doesn't seem to offer anyone (including me) who falls into that category (of being euthyroid and never considered by the medical establishment as hypothyroid despite symptoms to the contrary) any answers. My last TSH result was 3.8 and I exhibit all the signs of being hypo.

Or maybe I've missed something?

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No, but the chance of you having a TSH of that level and still being healthy is only 3% out of 100. This is what you need to say to your doctor. The 2.5 story is still controversial for many.

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Thanks Diogenes. Unfortunately I doubt very much my GP will take heed as she adheres strictly to protocol and whenever I raise symptoms such as extreme coldness in body extremities, low body temperatures, difficulty losing weight or severe fluid retention in the summer I get pat answers at worst or a brush off ("oh I get fluid retention too...") at best.

Having said this I have had some improvements since taking a number of supplements related to mytochondrial dysfunction and NAX and nutrithyroid products though there is a setback as the latter have been unavailable for a number of months.

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This is the basic problem. The patient in front of the doctor is an individual with their own individual solution of being healthy. But the statistical range for everyone is far wider. So just using statistics and saying " you 're in the normal range, therefore OK go away" cannot be right. The question is: " where in the normal range should you be for health, not a generalisation like the above".

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