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Thyroid UK
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Suppressed TSH, Osteoporosis and Atrial Fibrillation

My Endo is moderately reasonable (believes that Ferritin needs to be nowhere rock-bottom, for example), but still seems rather in thrall to the almighty TSH. she has told me, as so many Endos do, that a suppressed TSH leads to a greater risk of osteoporosis and atrial fibrillation; FT4 and FT3 values in range be damned.

I will be seeing her again on Thursday and would like to challenge her on this if I can, and in a reasonable manner. Therefore I would be grateful for links to studies / literature (if they exist) showing that a suppressed TSH value with a FT4 and FT3 value within the reference range is not harmful / runs no greater risk than for the average person. I have found studies which show that a very low (>0.03) TSH is not harmful wrt osteoporosis but atrial fibrillation wasn't mentioned. These studies concluded that having TSH <0.03 wasn't great news.

In addition, does anybody know what the increased risk for both osteoporosis and AF amounts to and what the baseline risk for the general population is?

Anecdotal evidence need not apply. You may well be someone who's gone for years with a suppressed TSH and in-range everything else with no problems but that's not going to do for my purposes.

Many thanks


11 Replies

Here is a very recent huge meta-analysis which actually pinpoints the risk in real terms. Whilst it exists, the extra risk is admitted to be small.

There has been recently in Clinical Thyroidal journal a meta- analysis paper on the risk of bone fractures in subclinical hyperthyroidism i.e. TSH's < 0.1 unit with normal FT4. No FT3 mentioned or done. I quote from the paper what I think is the culminating but less than impressive outcome:

Although the HRs for subclinical hyperthyroidism and all outcomes are significantly positive, the absolute excess number of fractures is still relatively small (i.e., 1 excess hip fracture for every 1000 person-years).

Subclinical Hyperthyroidism Is Associated with Increased Risks of Hip Fractures, Fractures at Any Site, Nonspine Fractures, and Clinical Spine Fractures in the Largest Meta-analysis to Date

To cite this article:

Leung Angela M.. Clinical Thyroidology. July 2015, 27(7): 174-176. doi:10.1089/ct.2015;27.174-176.


The link for the reference given by diogenes is :




The above link will take you to lots of previous posts on the topic of suppressed TSH.


I think the notion that a suppressed TSH causes AF and osteoporosis is a little dated now. If the TSH is suppressed and the FT3 is over range - then there may just be an issue. However they rarely test the FT3 so how would they know ?

An UNDER treated thyroid or UNDIAGNOSED thyroid problem is more likely to cause the above conditions....

1 like

Rubbish it causes neither!! Your doctor is living in the past and needs to change. You only get these problems if they are already part of your family history or several things come together, agree to disagree if you fell well there is no need to worry about suppression of TSH after all its a pituitary hormone NOT a thyroid hormone.


With respect Glynisrose, do you have studies / medical literature which says that a suppressed TSH doesn't cause osteoporosis / AF? (Regardless of whether there's a family history.) It may be a pituitary hormone but that doesn't mean it doesn't have other effects if too high or too low. Things rarely work in isolation.

However, I may ask my Endo by what mechanism suppressed TSH increases the risk of osteoporosis and AF, and write down what she says for the edification of us all :)


Sorry, I have checked out the studies and as usual they scare monger. Studies like clinical trials only come up with the answer they are looking for.


Unless the studies and trials come up with a result we like and then it's all smiles and roses, eh? ;-)

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You have to be discerning, these so called studies are all a sham. Its not a matter of taking the 'nice studies as fact its the vested interest that doctors have in the 'only'medication they approve of, who do you think pays for the conferences and other get togethers for doctors? Yes its either the pharmaceutical companies or people having a vested interest in theprescribing of levothyroxine.



Is this adequate hose1975 ?


That's grand, Marz. Many thanks. I haven't seen anything addressing the AF issue but will discuss further with the Endo (who will probably cut off my T3, I fear) on Thursday.



You can peep inside this book - on-line - and look at the contents. You will read that Liothyronine - T3 - is the star of the show. The book is based on research done in Italy when Endos and Cardios came together for the first time for the purposes of research !

Relevant papers are on PubMed - will have a look for you :-)


Surely prevention is better than cure !



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