I'm researching papers to help when drs say a suppressed TSH causes osteoporosis amongst other things. Many of us taking T3 do have a suppressed TSH, while T4 and T3 are not over range.
Is this paper actually saying it's the level of thyroid hormones themselves that can cause OP? (not suppressed TSH) I'm not clear on 'thyroid sensitivity'.
"Impaired sensitivity to thyroid hormone correlates to osteoporosis and fractures in euthyroid individuals" Feb 2023 DOI: 10.1007/s40618-023-02035-1
This paper uses data from "normal" people rather than on treatment. It indicates that a FT3/FT4 ratio (conversion efficiency) is correlated positively with bone density. That is, within the group, bone density is linked to this factor. Of those with lower FT3/FT4 ratios because of higher FT4 and lower FT3, there is a positive relation between the lower conversion rate and incidence of bone fractures. So it seems that in older age, a patient gets less FT3 from FT4 than that optimally maintaining the body, so FT3 goes down as FT4 goes up. You could call this thyroid sensitivity, whereas I would say, thyroid hormone production and conversion.
Also, I don't think TSH here is useful, at least for those on T4 or T4/T3. The relation between TSH and FT4/FT3 is quite different from 'healthy" people, so this paper doesn't relate to those on thyroid hormone.
As noted by diogenes the NHANES data is from the general population not thyroid patients. It's difficult to glean too much from the abstract and the full paper is behind a paywall.
TSHI (not TSH) was found to be negatively associated with bone density as was TT4RI. TSHI is described here en.wikipedia.org/wiki/Joste... and TT4RI here en.wikipedia.org/wiki/Thyro... . I don't like these indices, they smack of pseudo-science, trying to give numerical precision to vague concepts. It's worth noting that the negative correlations seem to all include measures of fT4. It looks like higher fT4 is associated with bone problems, hardly a good advert for LT4 monotherapy.
A good fT3 / fT4 ratio was associated with better bones.
The claim about impaired sensitivity to thyroid hormone is associated with osteoporosis and fractures is strange. Impaired sensitivity to thyroid hormone is usually related to peripheral tissues having reduced response to thyroid hormones. Also, the results make no mention of fractures yet it is included in the Conclusions.
Bones have TSH receptors and TSH has protective roles but the impression I've got is that this is a minor effect.
All the above is evidence that we should not use levothyroxine monotherapy as it requires a lower TSH, low fT3 / fT4 ratio and in general is likely to give greater bone risk than an equivalent dose of LT3, LT4 combination therapy.
Really need to see the full paper to judge how reliable it is.
what is considered to be a good FT4 to FT3 ratio?
Doesn't answer your question at all, but I have noticed several references to using ultrasound to measure bone density. If effective, it would potentially be a major step which avoids the X-ray radiation of DEXA/DXA and might well be considerably less expensive.
If it were cheap and safe, maybe people who have low TSH and/or higher levels of FT4 and/or FT3 could have regular tests?
europepmc.org/search?query=...
A bone density scan uses very little radiation, equivalent to three hours background radiation. The machine looks expensive but I assume it does x-rays for broken bones also. I suspect much of the cost is in expert interpretation not just getting the T and Z scores. I had a DEXA a few days ago, told results would be in a couple of weeks.
Exposure of about 4 mSv.
gov.uk/government/publicati...
But the issue of X-rays goes beyond a single DXA. They need to be repeated in order to keep a patient under observation. A peripheral DXA requires a central DXA to manage treatment - and that also needs to be repeated.
Further, the use of X-rays means the location (even if built as a trailer/bus - which some are) requires shielding thus increasing cost and weight.
It might also be possible to calibrate ultrasound devices more consistently. Seems that central tests should be done on the same actual machine every time.
Thanks for the link, I'll add it to the one I use radiologyinfo.org/en/info/s... . The bone scan in the UK government doctor is referring to nuclear medicine, giving someone a radioactive substance to study bones. DEXA scans use much less radiation.
If ultrasound can be made to work well it will be better, or at least another option according to individual cases.
I had a DEXA about eight years ago and one last week, so should be able to see how my bones have progressed whilst on reasonably high doses of LT3.
(another way of testing bones is to play football against Leeds United!).
You are spot on - afraid I scrolled down too fast!
Bone Densitometry (DEXA) 0.001 mSv
radiologyinfo.org/en/info/s...
It will be interesting for you to see your results.
But what we really need is a comprehensive study which includes people across the range of T3 levels, and over long periods.
So many biological systems end up with U-shaped curves. Both high and low being bad, but somewhere in the middle is fine. However, that is not meant to imply symmetry - it could be at either end the change is gentle or sharp. And a change from low T3 to adequate or high T3 might well represent a more complex situation.
Your last paragraph made me laugh 😂
I have recently had a Radiofrequency Echographic Multi Spectrometry (REMS) ultrasound scan which has been accepted by the Royal Osteoporosis Society as being as good as DEXAs. I wonder how similar this is to the one you have mentioned. The REMS comes up with a fragility score, which appears to be measured more accurately than the FRAX score of the DEXA when it comes to actual risk of future fracture, and the results are given straight away in a consultation during and after the scan. I had the scan because I have osteoporosis but do not want to take the drugs I was offered, have never broken a bone despite an active lifestyle for years, and was curious to see what the result would be - the fragility score it showed was a great improvement on the DEXA I had 7 years ago. As far as I know there are only two people carrying these out in the UK and the current price is £210, with quite long waiting lists.
pubmed.ncbi.nlm.nih.gov/332...
Framboise,
Interesting about this new machine and how great you have improvements 😃 💪🏼. There’s more sophisticated methods for monitoring bone health being used now.
Since starting T3, HRT & Vit D my DEXA’s have continued to show improvements, and because reversal of osteopenia is still unrecognised without meds such as bisphosphonates, I’ve now been asked to have a Beta-CrossLaps blood test.
This gives exact info on bone formation & resorption and is often used to monitor bone meds which I was originally offered but have always declined.
endocrinology.testcatalog.o...
That's very interesting thank you, I shall look into it 
Things are certainly changing - they have to!
In an osteoporosis group I belong to (for people who don't want to take the drugs) the REMS scan is showing that many DEXAs are incorrect to start with, taken incorrectly etc. Meanwhile the patients are taking drugs they don't need and never did need. HRT is now being offered by enlightened doctors in place of the bone drugs. I think the next few years are going to have many advances.
Please could you share the details of the group you belong to. Many thanks
I follow several blogs and get their newsletters: Better Bones, Marcelle Pick from Women to Women, and Save Institute for Natural Health - Vivian Goldschmidt, but the group I particularly like is a Facebook one called Osteoporosis UK ~ Friendly Support & Natural Options. If you aren't happy using Facebook, it's possible to set up an account in a fictitious name which you keep just for a group such as that one. I think that between all those, there's a huge amount of information and help for us to improve our bone health without the drugs. Good luck!
Many thanks for your reply. That’s brilliant!
I too belong to the same group and as a result, I am to have an Osteoscan done in June to satisfy my curiosity. Around 7 years ago I was diagnosed with severe osteoporosis via a Dexa scan having been on T3 monotherapy for 5 years. I did not go on the offered OP medication and have had no fractures despite falling downstairs on my back so hard I got a detached retina. Plus other falls...
I have been on recommended supplements during this time. I did initially lose 1.5 inches but this stabilised and I lost no more. Also I am still on T3 monotherapy courtesy of the NHS (a kind of 12 yr miracle ha ha!).
Many thanks for your reply. It’s encouraging to know that the right supplements help so much. I hope your scan goes well.
Thank you LynLyn.
TaraJR,
'Conclusions: In elderly euthyroid individuals, impaired sensitivity to thyroid hormones correlates to osteoporosis and fractures, independent of other conventional risk factors'.
We don't need science to confirm this as see it through experience and I don't understand the language of your paper 😬, so put simply as I see it -
TSH has influence on bones but not when its low, and never as much as FT4:FT3 ratio which drives and retains healthy bone formation and absorption. Too much thyroid hormone will cause bone absorption to exceed bone production with a net loss of bone mass, and inadequate thyroid hormone results in both bone resorption and production decreasing and resulting in fragile brittle bones. TSH has receptors within bone and is only influential when high.
Other factors are oestrogen and progesterone, both major contributors for optimal osteoblast activity, and gut health allowing good usage of nutrients and particularly Vit D to allow calcium absorption. Further considerations are age related or illness that change the patterns of the three thyroid hormone activation/deactivion enzymes (D1, D2 & D3), as T4 converts to T3 within bone cells by D2 enzyme expression but only some bone cell types are equipped with D3 enzyme that deactivates (stops excess thyroid hormone working).
I think the lovely tattybogle has further papers on thyroid hormones and bone fractures.
TaraJR if you don't have them already , the first 3 papers on this list relate to fractures / bones density / low TSH : healthunlocked.com/thyroidu.... useful-evidence-that-tsh-between-0.04-0.4-has-no-increased-risk-to-patients-on-levothyroxine-as-long-as-ft4-and-ft3-are-in-range-.
I have Osteoporosis and Multiple Spine fractures, 1st fracture t7 5 1/2 years ago followed by t4, t1, t2, t11 and B12 + 3 Lumbar fractures and Cervical cracks/osteoblasts/osteophytes etc.
I won't take the dreaded bone meds e.e.g Alendronic acid, Prolia, teriparitide etc.
I didn't know before having the fractures that my Vitamin D was low.
I believe Vitamin D 5000iu 1 Day, 10,000iu the next, Vitamin K2/MK7 300mcg, Magnesium up to 400mg (my gut doesn't like Magnesium), pink Tribe Liposomal Vitamin B Complex, Selenium, Methylfolate, 400mcg, taurine, Alpha lipoic acid, eating more protein = fish, chicken, boiled gammon, lamb or beef has strengthened my bones noted by much reduced pain and more flexibility.
Nonetheless, my TSH has never been 'good' hovers around 3, ft4 around 12.
I have Blue Horizon Medicals blood tests to carry out in a Weeks time so I'll find out what ft3 is also then + Vitamins etc
Thyb,
Sorry to hear about your poor bone health. If your gut doesn’t like magnesium there are different forms better tolerated or you could try ReMag which is a liquid that’s absorbed before it hits the stomach as the molecule are so tiny. It’s expensive but potent so last for ages.
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