Hello everyone question re Low TSH and osteoporosis

Hello everyone I recently joined this forum and wanted to say hello and ask a question. I've been on levothyroxine for many years, I have Hoshimoto's. My TSH levels have been too low for some time and based on this whenever my thyroxine is reduced I become very hypo and cannot manage. Some years back I saw an endocrinologist who told me to stay with the slightly higher dose and not worry too much about TSH. And I've been largely fine for many years. But a few months ago I was told I have osteoporosis in my lower back and it was suggested to me that it's because I overdose on thyroxine. I don't actually overdose I take 100 a day and twice a week 125. I went on 100 for 2 months but felt really low on energy and actually became depressed and developed all kinds of weird symptoms. Anyway I've been back to GP and back to the specialist ( a very senior thyroid person in UK) and none of them can tell me if too low TSH ( or too much T4) has caused my osteoporosis. I had various blood tests and the only other thing was a slight deficiency in vitamin D which I am supplementing now.

So my question is, can taking a little too much thyroxine on which I feel fine but which lowers my TSH too much cause osteoporosis. Would welcome some views. By the way have read posts on this forum and it's so great! Wish I'd found it years ago.

10 Replies

  • If you have too low a TSH it can lead to osteoporosis, specifically if the TSH is suppressed. It depends upon your age and other factors like vit D and menopause. This information is based on population surveys which look at TSH in the general population and compare osteoporosis rates.

    It gets much more complex. For example, patients with thyroid cancer often require TSH suppressive doses of levothyroxine and do have osteoporosis higher osteoporosis rates. However, these patients often have disruption to the parathyroid glands also (so named because they are located next to the thyroid). The parathyroids are resonsible for bone metabolism, so it is hardly surprising if there is osteoporosis.

    Another issue is that looking at TSH in the general population is not the same as in a specific patient. If that patient requires a lower TSH to be clinically euthyroid it is not the same as reducing another person's TSH to the same level.

    Also, although these is evidence that a suppressed TSH reduces bone density there is no increase in fracture rates. A patient restored to normal health is able to exercise and build up bone strength.

    Your doctors can't tell you if your low TSH has caused your osteoporosis, nobody can. My judgement, as a patient, is that if you reduced your medication and your TSH rose it might reduce the chances of further osteoporosis but the loss of exercise capability would be just as bad. If it were me I'd take the minimum dose that resolves my symptoms and look at ways I can mitigate any osteoporosis, such as vit D and weight bearing exercise, maybe days out in the sunshine! Other factors are likely to have a greater bearing on osteoporosis.

    If I remember correctly it is suppressed (almost undetectable) TSH that is associated with osteoporosis and not just a low TSH, not just below the lower limit of the reference interval.

  • Thanks jimh111. My problem is that when i reduce my thyroxine i just cannot function. I am going to try and make sure my vitamin D levels stay optimal from now on. Re weight bearing I used to run and amsl swam and did weights in the gym regularly for years....but had so many problems with backache and knee ache and general aches and pains. I persisted despite all that but but then in january when i had reduced my thyroxine because of fears re osteoprosis, I developed knee pain so severe that it put me in crutches (for no clear reason, although there was an old knee injury many years ago). So only just managing to walk properly now. I am having physio and on his advice i've just bought an exercise bike and am starting on that with a daily program. and will slowly incorporate weight training. just need to decide on how to cope with low thyroxine or risk of further osteoprosis. I am 56 years old and the osteoprosis in my back is apparently something i could expect 20 years from now in "normal" circumstances.

  • That sounds like more than enough exercise! I was thinking of going for walks or gentle lifting. I'd take enough levo to make yourself well. Hypothyroidism seems to cause sensitivity to pain leading to less ability to exercise etc. Is seems you have the choice of having a life with levo or cutting back, having no life and getting just as much osteoporosis if not more.

  • Osteoporosis can happen with or without an accompanying thyroid disease. Therefore ascribing a "cause and effect" hypothesis to whether slightly higher thyroid supplementation was the cause of OP is very nebulous. You might well have got OP even if you'd not had thyroid trouble. It really isn't possible to say for one individual what was the cause. Alternatively like my wife, you can have suppressed TSH for 45 years on T4 and have no osteoporosis but have arthritis instead. Still no cause and effect, just the wear and tear of getting older.

  • thanks. i agree it is hard to ascribe "cause and effect" in general as we are all different. but specifically for me, if i could be certain that having slightly higher thyroxine is not going to worsen my early onset osteoporosis it would be of great help to me. but i am not sure if i can find this out. At the moment i have a choice between being hyo and not functioning or risking serious bone disease early in exchange for being ok now.

  • Afshan64,

    My TSH is to be suppressed <0.1 to avoid recurrence of cancer. I was diagnosed with mild osteopenia 2 years after TSH was suppressed. I doubt the TSH has anything to do with it and I think osteopenia is more likely due to early menopause <42 and severe vit D deficiency found in 2013.

    This article finds no increased incidences of osteoporosis in 4 groups of thyCa patients with varyihttp://www.ncbi.nlm.nih.gov/pubmed/24761409ng degrees of TSH suppression.

  • I thought it was over range T3, not low TSH, that was implicated in osteoporosis. Many people with "normal" TSH have osteoporosis - just as likely to be low magnesium, zinc and boron or too much calcium, or just generally being too acidic.

  • drmyhill.co.uk/wiki/Osteopo...

    You may find the link above to Dr Myhill's website and her points on Osteoporosis of help - you will see all the supplements that are part of bone building ! When taking VitD it is also good to take a VitK2 capsule to direct calcium away from the bloodstream and into the bones ....

    There is a piece of research saying that suppressed TSH does not cause OP - am still looking for it :-)

  • Most of us are happier if the TSH is suppressed.

  • Have you ever had your FT3 tested? There is an awful lot of difference between having a suppressed TSH due to over-range FT3 when you are hyper (Graves etc) and having a suppressed TSH due to thyroid hormone replacement - and, sometimes, quite a small dose can suppress the TSH, not necessarily being over-dosed. Most researchers agree that it is the excess of T3 that increases your risks - it's not a fatality - of getting osteoporosis, not the fact that the TSH is low. Doctors can't seem to get their heads around the difference.

    Its quite possible that your vit D has been low for some time, and that is the reason for your osteoporosis - if osteoporosis it really is - could it not be that your bones are thinner because of your age (no idea what your age is, though). You can't expect to have the bones of a 20 year-old at 65. But doctors tend to forget that.

    I think you should keep your levo at a dose you feel well on, and take your vit D3 with K2 - as Marz says - and magnesium. Magnesium is very important for bones, and most of us are deficient. And I would stop worrying. Low thyroid hormone is far more likely to have an adverse effect on your bones than a dose that makes you feel well. :)

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