This paper has probably been posted before but no harm in posting it again as many will find it useful to present to doctors obsessed by low TSH. It concludes that supressed but not below range TSH is a factor in cardiovascular and bone disease.
SUPRESSED TSH: This paper has probably been... - Thyroid UK
SUPRESSED TSH
Actually, it talks about a 'low but not suppressed' TSH. You cannot have a suppressed TSH that is still in range.
Patients with a high or suppressed TSH had an increased risk of cardiovascular disease, dysrhythmias, and fractures, but patients with a low but unsuppressed TSH did not. It may be safe for patients treated with T4 to have a low but not suppressed serum TSH concentration.
Which really isn't much use at all to those taking T3. In fact, it buys into the doctor premise that TSH must be kept in-range. And, you cannot take seriously a research paper that doesn't mention FT3 once. Sorry.
Thank you for being there to help decipher these papers which I find challenging.
I have GRAVES and at different times my TSH has been suppressed/ low/ in range/high.
When supressed and low I was warned about CV and bone disease.
Although this paper referred to people on T4 therapy I picked up on their conclusion of no increased risk for those with low TSH which I had at the time and felt it could POSSIBLY indicate that I too was at low risk of CV and bone disease which reassured me a bit. With so little evidence around I find I am reduced to using any little bits I can find as there is no good scientific evidence yet.
Well, I think there is. Have you looked through diogenes ' posts on here?
healthunlocked.com/user/dio...
Thanks I will have a look and update myself as it is a while since I gathered all the evidence to help me decide if I should go with TT/RAI or drug treatment.
What a great list of useful articles from Diogenes. However I have had a quick look and although there are studies advocating use of fT4/fT3 measurement rather than over reliance on TSH I cannot find a scientific paper that shows low TSH does not increase the risk for CV and bone disease. ( neither is there one showing it does ) Hence my interest in this paper. Does anyone know of one I've missed ?
Sorry, I thought there was. I'll have a look and see what I can find.
How about this:
"Conversely, subclinical hyperthyroidism occurs when T4 and T3 levels are within their reference ranges, but the TSH concentration is suppressed below its reference range. The effect of subclinical hypothyroidism on bone mineralization and fracture susceptibility has not been studied extensively [1], but a recent individual participant meta-analysis of data from 70,298 subjects from 13 prospective cohort studies consisting of 762,401 person-years follow-up demonstrated no association with fracture [28]."
ncbi.nlm.nih.gov/pmc/articl...
healthunlocked.com/thyroidu...
healthunlocked.com/thyroidu...
healthunlocked.com/thyroidu...
Read diogenes' comment.
This doesn't directly relate to your quest, but I thought you might find it interesting:
Thank you so much greygoose for your tenacity in finding these. I am very grateful and I am sure many others will be too to see this evidence that we are not at great risk. It is late and I have had a glass of wine so I will leave closer scrutiny till tomorrow.
Cheers !
Yes, I think that might be best! lol I'm still looking for something that relates to hearts. I was sure I had something, but I'm having trouble finding it.
I thought that was a typo, but I think it is talking about subclinical hypothyroidism. The bit below is about subclinical hyperthyroidism. Thanks very much for posting, useful thread and I will look through all links too!
‘More studies have investigated the relationship between subclinical hyperthyroidism and BMD or fracture risk [1] and large population studies have suggested an increase in bone turnover, decrease in BMD and an increased risk of fracture, especially in post-menopausal women, although heterogeneity between studies prevented firm conclusions in several meta-analyses and reviews [32–38]. Nevertheless, the recent large individual participant meta-analysis of data from 70,298 subjects demonstrated that a TSH value below 0.01 mU/L was associated with a 2- and 3.5-fold increased risk of hip and spine fractures, respectively. Overall, subclinical hyperthyroidism was associated with bone loss and fracture, particularly in individuals with endogenous disease [28]. Furthermore, a register-based cohort of 222,138 subjects with a normal TSH level plus 9217 individuals with a low TSH were followed up for 7.5 years. This study demonstrated an exponential association between the duration of thyrotoxicosis and fracture. In euthyroid individuals, the risk of fracture increased with each standard deviation unit decrease in TSH (hazard ratio 1.45, p < 0.001 for hip fracture; HR 1.32, p < 0.001 for major osteoporotic fracture) [39]’
That was the first paper you linked to I should add!
I'm sorry, I'm not clear on the point you're making, there.
Sorry if unclear. I thought you might have accidentally pasted the wrong segment, as this was the bit relevant to the OP’s discussion regarding suppressed tsh. When I read it I thought subclinical hyPOThyroidism should have read subclinical hypERThyroidism. Sorry if I am being pedantic I just noticed this and took a look as I was interested in the issue also. X
You're possibly right. I shall have to look at that again.
Isn't the risk of too high FTs (FT4 and FT3) the real problem when you have Grave's? That would result in a suppressed TSH, but that does not mean the TSH in itself is the problem, but the out-of-range free Ts (which are the actual thyroid hormones).
Absolutely agree. Unfortunately many docs don't know that and still give dire warnings of CV and bone disease. Hence my interest in this paper. When my TSH was low I could say it wasn't harmful.
I agree! Many people on NDT or T3, myself included, have a very low, even suppressed TSH, with no ill effects. I have Hashimoto's so the only cause of TSH suppression in my case has been drug-induced.
I have very low tsh and always have done since Graves, I now have atrial fibrillation and will either need ablation or pacemaker so maybe it is an issue for some.
But, if you had Grave's, surely you had a high FT3, the active hormone? Don't you think it's more likely to be that caused your heart problems, than the TSH itself?
If it was caused by Graves I think it would have occurred sooner as I've been hypo for well over 15 years with T3 only mid range tsh usually around 0.03 and no heart problems until now. It doesn't really matter what has caused the AFib because I can't do much about it unless raising my tsh a little would help, who knows.
You could try it and see if it would help.
So what figure would be defined as suppressed TSH and what would be considered low TSH, please?
Doctors consider that 0.1 is suppressed. I would have thought it was more like 0.01, but that's just me. I would imagine that definitions of 'low' vary from doctor to doctor.
I guess there are no exact rules, but a low TSH to me be would be somewhere near or at the very bottom of range, say 0.2-0.5 (I'm using "my" lab's range which is 0.2-4.0).
A suppressed TSH would be below 0 (or even 0.1 if interpreted strictly).
But that's just my interpretation.
The ranges quoted in the paper I referred to were:-
Supressed under 0.03
Low 0.04 - 0.4
Normal 0.4 - 4
Raised over 4
However as what is normal is debatable I imagine it can only be a rough guide.
Well, I guess there are subcategories as well as 0.2-0.5 could also be called "low normal"...some doctors (with a more holistic approach) call a TSH below 2 (or no higher than 1.5) "optimal" whereas a TSH close to 4 is considered "highish" since hypo symptoms often appear before the TSH is clinically out of range...not an easy subject, is it?!?
In the early days of TSH testing, using what are now called first generation assays, the lowest detectable was still quite significant. Below that level was regarded as suppressed as in "too low to be measured". Second generation, and now third generation TSH assays have increased sensitivity considerably. But no-one has formally defined or re-defined "suppressed". Wholly unsatisfactory.
Thanks, that was timely and interesting for me
The problem with this paper that I can see is they admittedly only looked at TSH levels: high, low and suppressed but did not take into account FT4 or FT3 levels.
We have no indication if those suppressed figures have a corresponding over range FT4 levels which would lead to a higher risk for AF and osteoporosis.
So the paper appears flawed unless I'm missing something else.