Thyroid UK
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Are you a smoker?

If the answer is "yes" you may want to have a look at this (unfortunately the complete paper is not accessible). It might be that not smoking the day of your TSH test could produce a higher TSH result.


The association of cigarette smoking with serum TSH concentration and thyroperoxidase antibody - Mehran L, Amouzgar A, Delshad H, Azizi F.

Source- Endocrine Research Center, Research Institute for Endocrine Sciences, Shahid Beheshti University of Medical Sciences, Tehran, IR Iran.



Although several studies have found an association between tobacco smoking and thyroid disorders such as Graves' disease, Graves' ophtalmopathy, goiter and thyroid multi nodularity, the effect of smoking on thyroid function is controversial.


The aim of this study was to evaluate the association between smoking and serum TSH concentration and the presence of thyroperoxidase antibody (TPO Ab) in Tehranian adults.


In this cross sectional community based survey, 1,581 randomly selected subjects with no history of thyroid disorders were studied within the framework of Tehran Lipid and Glucose Study. Serum TSH and TPOAb were measured in a fasting serum sample. Weight and height were measured and BMI was calculated. Smokers were classified into ever and never smokers based on the declaration of participants.


Mean Ln TSH values in the ever smoker (0.36±0.82) was significantly lower than the never smoker (0.6±0.82) group (p<0.001) even after adjustment for age and BMI. The odds ratio for hypothyroidism (TSH>5.8) was 0.4 in the ever smoker group compared to the never one (odds ratio 0.4, 95% CI=0.2-0.8). The frequency of positive TPOAb in never smokers was significantly higher than ever smokers (%13.5 vs. %?6.7, p<0.001).


The results suggest that smoking is associated with decreased serum TSH concentrations, lower risk of hypothyroidism and possibly with a lower frequency of thyroid auto immunity.

© J. A. Barth Verlag in George Thieme Verlag KG Stuttgart · New York.

I'm not sure I like that you have a lower risk of hypothyroidism and autoimmune thyroid disease if you smoke!

Carolyn x

37 Replies

and that Thryoid problems tend to appear when we quit? J


And anyway, that is in Iran. Physiology is different there. Science is different there. :-)

Seems all too likely given the repeated "I gave up smoking and ended up hypo" story - mine along with many others.


Rod, I am being particularly obtuse today (lack of sleep). I'm presuming you are being ironic? I'm really bad at irony and other such humour so I may have got it completely wrong ;)


It is just that people have a strong tendency to dismiss anything that comes from another country - especially if they are culturally distinct, many miles away and portrayed as evil in the news. So anything from Iran is bound to be treated with the deepest suspicion.

But the bit about me giving up was spot on true.


Thanks for clearing that up :) I can be very literal and occasionally when I think people are being ironic or sarcastic they are not! I still haven't worked out how to tell, even when I am face to face with them. Luckily, everyone who knows me is very understanding or I could end up in trouble!

In this case it was the statement about science being different in Iran that led me to think "irony". Being a physicist, I cannot accept that statement :D


I understand - we all have things we don't "get". :-)


Yep my tsh was 2.8 December so I started smoking again and it was 0.8 two months later so I am a firm believer.


I am muddled now, I was diagnosed with copd and eventually gave up smoking, was diagnosed hypothyroidism not long after? was the the stopping smoking that caused it? that would be awful because apart from the copd I have never felt so ill with autoimmune / fibromyalgia since stopping!


It is more likely that stopping "triggered" it and that you would have developed it eventually anyway (that's my understanding so far). Also there's all the other risks associated with smoking, and with COPD I imagine it was pretty crucial to stop smoking.


Folks report that Thyroid problems come to the fore when they give up smoking, perhaps nicotine intake 'masks' the problem for a while? who knows - there's quite a few previous discussions if you use search - here's one....

Jane :D


The risk of receiving a diagnosis of overt autoimmune hypothyroidism is increased more than six-fold in the first 2 years after smoking cessation. Clearly, smoking cessation is vital to prevent death and severe disease. However, awareness of hypothyroidism should be high in people who have recently quit smoking, and virtually any report of symptoms should prompt thyroid-function testing.

This and more smoking related info on our main Thyroid UK website here:



Thanks Red, good to see actual studies. Hopefully one day docs will realise the possible connection. I always wonder if B3 is involved (nicotenic acid) ?? J :D


Ooo! Interesting :D

I was kind of in a hurry because I had to go out but wanted to post something. This is much better though!


Yes! I gave up smoking almost three years ago (May). Since then I have put on two stone in weight, have become depressed, feeling half of the person I was before quiting smoking, I have lost my confidence, and I miss having a fag now and then!! I was diagnosed with underactive thyroid Sept 2010, so the coincidence with stopping smoking it happened 4 months later! I would rather have 20 malborough than take Levothyroxine, as taking levo has knocked the life out of me.


I really wish in a way that I had never stopped! I thought I would feel so much better, I feel really sad about it, now stuck on this horrid levo,


Trouble is, we'll never know whether the smoking was simply delaying the inevitable and it was going to happen somewhere along the way regardless.


That's what I wonder. I also wonder if people would have suffered with hypothyroidism if they had never smoked.

I seem to remember reading that nicotine replaces a substance that the body normally produces itself but as it is getting it from cigarettes, it no longer needs to make this substance. When you stop smoking it can take a while for your body to start making it again, hence the withdrawal symptoms.

I wonder if this is a similar effect to the adrenal insufficiency resulting from stopping steroid treatment...


It sounds like either you are on too low a dose or you need some T3. It's awful when you do something to make you feel better and be healthier and you end up feeling worse than ever :(


I just checked my diary, says, " stopped smoking 29/4/2011, got diagnosed with hypo 16/1/2012, nine months later, I went to doctors due to all the pain I was in, the pain has been with me ever since, I am now registered disabled, have a blue badge, and cant walk far, I have tried all the recommended supplements, can't get T3 for love nor money , your so right Carolyn, it's so upsetting when you try to do the right thing and end up like this, I was told that once your put on levo, that's it for life, its so sad,


I hope you find a solution eventually. It does sound like T3 could be the answer. I'm sorry you can't get it prescribed :(


susie59, sorry that you had this experience: I agree that stopping smoking was the right thing - although to be totally honest, not smoking at all in the first place would have been even righter! I'm not trying to preach or be unkind here, as I am sure you know it anyway.

What happens is that according to the research, TSH levels are reduced in smokers. I wonder if there is something in the smoke which gives you enough of a boost to overcome the tiredness of not enough thyroxine (due to lower TSH output?) Maybe one day they will discover that is the mechanism which causes heart problems and circulation problems in smokers? The reason I say this is that I have an enlarged heart and valve problems caused by being starved of thyroxine for 6 years. I have never smoked. But both my parents did.

Whatever the truth, I think giving up smoking is not CAUSING the problem but REVEALING it. Whenever my mum tried to give up smoking (in her 70's) she would get serious breathing problems, but when she started again she would 'cough it up' as her neighbour so appealingly put it. So the problems were still there but stopping revealed them. She died of COPD.

If you are still in so much pain, are you being properly treated? It sounds as if not. Have you put your blood results on here?


This is a quote from Mary Shomon:

The Relationship Between Quitting Smoking and Thyroid Disease Onset

While I don't have an answer as to whether or not stopping smoking "triggers" problems with the thyroid -- as it anecdotally often appears to be -- it is clear that medical researchers have found that smoking can worsen hypothyroidism in people that already have it, and smoking can seriously affect thyroid function.

My theory is that smoking/nicotine creates an artificially high metabolism that masks the fatigue/lethargy commonly seen in hypothyroidism. When the smoker quits, this masking is removed, and the full effects of hypothyroidism on the metabolism and thyroid are felt.

And, for smokers with undiagnosed thyroid dysfunction, without proper thyroid hormone treatment, stopping seems to be a metabolic/weight gain double whammy, as they lose the appetite suppressant, metabolism-upping effects of nicotine, and experience the full effects of the hypothyroidism.


thanks so much for your reply, I think you are right, its not really so much as giving up smoking causing the problem, so I know I did the right thing really, I am sorry your mum died of copd, mine did too, so I am glad I stopped, I think your right about not being properly treated, my doctors doesn't really seem to know and just follows the basic levo/results path, I have previously posted my results a few times and had good advice from rod and carolynn etc,

my health authority has started to only test TSH, not even T4 any more, so its not much help, I am going to beg my doctor to refer me to an endo, I did try before but got no where, but a year has passed now so maybe I will get it this time,

take care, x


I seem to have the same difficulty. I asked a year ago and was totally ignored. Then when I nagged him so much that he increased the dosage, he said 'And if you're still not satisfied, you can see an endocrinologist!' I actually said - that's what I asked you for a year ago. Still no referral.


it is a nightmare, trying to get blood out of a stone!

my GP has let me increase, and he does agree a lower TSH usually helps , I think he is tied by the practice in so much as cant give T3 or get tests for it, I do have about 2/3 blood tests a year for TSH and he did try and get the T4 test back for me, but the lab wouldn't do it, I will try for a referral next time, but I think it all comes down to money perhaps?


I can see that it must be a really tough thing, but if you put it in proper perspective, my smoker dad died at 55 of pneumonia due to underlying previously undiagnosed lung cancer, and my smoker mum died at 80 of COPD, having been incapacitated for 24 years and spent an average of 8 weeks in hospital each of those years.

I was diagnosed with Graves' disease at 13 years of age .. this study suggests that there is a correlation between smoking and graves' disease. I was obviously not a smoker but I lived in a smoking environment, and also my brother who had pneumonia four times before he was 5.

I had a really good friend who was a chain smoker and when she was homeless she lived with me for a time. In that time she tried to stop smoking, I saw what she went through - it was sheer agony for her. How much better if she had never had to go through that.

Are you sure it is the Levo and not the hypothyroidism which is knocking the life out of you? Maybe you need to be treated better?


Well I smoke and have autoimmune hypothyroid :-(

I hope when I finally manage to kick the habit I don't feel worse than I do now!

To all of you sensible people who are already non smokers DON'T start again x


Agree! J x


I'm sorry :( That really is rotten luck! I'm determined never to smoke again. I'm fairly sure my hypothyroidism became overt (as opposed to "borderline") after stopping smoking but I could be wrong. So much was happening around that time!


Have a look at Mary Shomon's comment I quoted above. Her thought is that the metabolism boost of smoking can be masking the underlying hypo symptoms which are the result of TSH suppression.


Thanks. I did have a look and I think she is right.


Wow, interesting thread. I'm right on the zeitgeist here!

I recently started again. I was another whose hypo/cfs symptoms came up literally weeks after quitting nearly ten years ago, with high TSH and elevated TPO. I'd smoked for about 16 years from about age 16.

Started again lately just down to various stressy things and have a friend or two who smoke so I was cadging the odd cigarette from time to time and enjoyed it.

After a couple weeks on just 2 or 3 a day I've felt sick, grey, poisoned and increasingly craving my next one. It didn't seem to alter fatigue levels, still pretty low on energy either on or off the cigs.

I had my 'last' cig yesterday and gave away my tobacco and feeling the craving pangs now.

NOW I'm tempted to start again as a clinical trial on myself and then go and get my blood tested! But that's probably just the cravings swaying my better judgement.

Very interesting study outcome though. Hmmmm. Hmmmmmmmmm.


So how does smoking dampen down tpo ab or delay hypothyroidism? Is it the nicotine? I sure as hell don't want to start smoking again and if memory serves I certainly had my 'poison body feeling' the name I gave to what I now know we're autoimmune flair ups when I was still a smoker! This is very interesting. It's a shame the study didnt isolate or have an idea about what was causing the positive effect.


It would be very interesting to know wouldn't it? I suppose it could be the nicotine. I see some reading in my future :D


I gave up smoking in March 2012 and began showing symptoms of hypothyroidism almost within a 2 weeks. I was diagnosed August 5 months later. I even told my GP that giving up smoking is what started the thyroid problems but she just looked at me strangely.


Not sure if anyone will see this now as the discussion took place a couple of months ago, but I think I'm proof that there is some kind of link between stopping smoking and certainly Graves disease. I smoked from the age of 18. When I was in my early 40's I made my first serious attempt at stopping smoking. I lasted probably about 3 months. I also started with my first encounter with a hyperactive thyroid problem. It started mainly with bad fluid retention in my feet. Eventually I was told I was borderline hyper and the consultant decided not to treat it. A few year later and I tried stopping smoking again and although my swollen feet never really went away properly from the first time, they started to swell very badly, then I had all the other symptoms, pounding heart, palpitations, tremor in my hands, blurred vision, and was treated with carbimazole this time for 18 months. In the meantime I had started smoking again and with the treatment the swelling in my feet completely vanished. I have been fine for the last 3 years since I came off the carbimazole, indeed I lost 3 1/2 stones on a weightwatchers diet and was very fit and healthy apart from smoking. In January this year I decided to stop smoking again. I'm still not smoking but my feet are starting to swell again, I'm putting on weight, though I think a lot of it is fluid retention and as I am still in the midst of quitting I still use nicotine lozenges to help with the cravings. The lozenges have started to increase my heartbeat noticeably though I haven't noticed any palpitations yet. So yes there is definitely a link.


This is really interesting. I quit smoking when I found out I was pregnant with my daughter in 1996. I quit when I was just 2 weeks pregnant. Had some homeopathy to help me then. I gained a lot of weight during the pregnancy but my doc kept saying, no problem. I can attest to the fact that I must have become hypothyroid but it was not diagnosed until my daughter was 6 years old! I had gone back to smoking when she was age 2...why? Stress, could not lose the baby weight (!) and death of my father all made me start again. I wish I hadn't but that was the only way I thought I could lose the weight, get through it. Looking back was it the quitting smoking which brought on the hypothyroid?? Now, here I am again, just about to try and quit smoking again, am reading all your posts and wondering now if I should??? Can it really be that quitting smoking makes us more ill! GOD is there no mercy for us thyroid people?????????????


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