I'm not sure how much "proof" this paper provides of a link. But it certainly points a finger at there being a link between hypothyroidism and cataracts.
Hypothyroidism is a causal determinant of age-related cataract risk in European population: a Mendelian randomization study
Abstract
Objective: To determine whether there is a causal relationship between thyroid dysfunction and the risk of age-related cataract (ARC) in the European population.
Design: A two-sample Mendelian randomization (MR) study.
Methods: Hypothyroidism, hyperthyroidism, free thyroxine (fT4), and thyrotropin (TSH) were selected as exposures. The single nucleotide polymorphisms (SNP) of hypothyroidism and hyperthyroidism were obtained from the genome-wide association studies (GWAS) of the IEU database, including 337,159 subjects. Data for fT4 and TSH (72,167 subjects) were extracted from the ThyroidOmics Consortium. ARC was used as the outcome. The SNPs associated with ARC were selected from a GWAS of 216,362 individuals in the FinnGen database. The main method used was the inverse variance-weighted method, together with four complementary methods. Sensitivity analyses were performed using Cochran's Q test, MR-PRESSO, MR-Egger regression and leave-one-out test. MR pleiotropy was used to test for pleiotropy. MR Steiger test was used to test for the directionality.
Results: Two-sample MR analysis revealed a positive association between genetically predicted hypothyroidism and risk of ARC (OR = 2.501, 95% CI: 1.325-4.720; P = 0.004). Hyperthyroidism, circulating fT4 and TSH levels did not have a significant causal effect on ARC (P > 0.05). The results were robust and reliable, and no horizontal pleiotropy was found after sensitivity analyses. In the MR Steiger test, we found no reverse causal effects of hypothyroidism on the ARC (P <0.001).
Conclusions: Our study provides strong evidence that hypothyroidism is a causal determinant of ARC risk.
Keywords: Mendelian randomization; age-related cataract; genome-wide association study; hypothyroidism; thyroid.
Interesting. I have significant family history of cataracts—my maternal grandmother (diagnosed with hypothyroidism and I suspect left undermedicated for years given how much hair loss she suffered) had them, as did my paternal grandmother who was never diagnosed with hypothyroidism but was significantly overweight at a time when most people of her generation weren’t, despite not appearing to overeat. My father also had cataracts.
I guess it remains to be seen what happens to me. I think I’ve always assumed it will happen, given my genetics. But let’s see…
I would have liked to know more. For example, does it just happen with untreated hypothyroidism, or those people on levothyroxine only treatment, or combination T4 + T3 treatment, or T3 only treatment. Does it only the affect those people with a poor T4 to T3 conversion ability? They are looking at genetic susceptibility, but these genes aren't always switched on - what happens in this case? As you can see, this left me with a lot of questions - though bear in mind I have only read the abstract and conclusion.
I don't think I can explain it any better than the abstract itself!
Definitely more of a link through the same genetic variants than an explanation of the mechanisms. I think we are going to see a huge number of this sort of study. But it will take much more work to explain them.
Im not sure I agree. My husband has cataracts and he does not have a thyroid condition nor did my father who also had cataracts. Sun damage is a known issue along with lots of other issues that can cause cataracts.
52 posts amongst 165,427 posts is a tiny tiny reflection. If you look for something amongst a community this big you will find lots of things that others have but it does not mean that it has anything to do with the thyroid. Sorry but I think its a reach too far.
But it’s only statistical risk they never said 100% of those with cataracts are also hypothyroid . There’s a big difference. There’s unlikely to be one cause ie hypothyroidism . Seems pretty convincing to me that one can cause the other
The mention of 52 posts wasn't meant to shout from the rooftops that everyone here has, or will get, cataracts. It was to point out that the issue has been mentioned. And to provide links back to those posts - I imagine some members remember some of the posts, or at least that there have been such posts.
And the genetic issues which suggest the relationship of hypothyroidism and cataracts do not predict thyroid issues in individuals.
Your husband and father could have the same genetic variants which sometimes lead to hypothyroidism but that never happened to them. Or they could not have them, and got cataracts anyway.
That does not mean they did not have the same genetic variants.
Variants can have been in existence for millennia, or be de novo, and the exact same variants sometimes appear with absolutely zero possibility of inheritance.
Considering all those people come here to discuss thyroid issues I very much doubt many of them would even imagine that cataracts could be associated with their thyroid issue, like so many other random things that effect us like frozen shoulder, gallstones, carpal tunnel or plantar fasciitis to name but a few...
Medics like to deal with one problem at a time rather than a holistic approach so rarely put 2 & 2 together and realise there is a root cause
I've got cateracts developing and have never mmentioned them on this forum. So I'm one of those people who have hypothyroidism who have never said anything about cataracts.
Actually Hypothyroidism and gallstones have a well documented link! I have had direct experience of it too. Hypothryoidism - the gift that keeps on giving
Yes most of these conditions are documented if people thought to look but when you are a muddle headed poorly treated Hypo you often don't think to research your condition as you (often wrongly) assume the GP knows about it 🙄
I personally didn't have a clue before I joined the forum
It took me 20 years of levothyroxine treatment before I started investigating hypothyroidism for myself to see if i could find answers to why i felt so rubbish. To be fair my GP at the time was searching too and put me in touch with an NHS endo who was experimenting with adding T3 to levothyroxine thyroid meds. It took me even longer to find this forum.
I have cataracts, my father had them but he wasnt hypo, yet I inherited hypo from him as nearly all his siblings, his mother and my female cousins on that side have hypo.
Thanks for posting this. Very interesting. I recently had my yearly eye test and found out that I have a cataract coming in one eye. I was a bit shocked. I did wonder if it was linked to hypo.
I have just been diagnosed with a cataract a fast growing one but not in the normal place. It is at the back of my eye. I only have had one aunt with cataracts and that was when she in her 80's. She was also diagnosed pre-diabetic. Although she was as skinny as a rake and ate very well.
Apparently it is unusual to have it in one eye. After they did all the tests as they seem to think it is rare and denotes a tumour at the back of the eye, thankfully I was in the clear for that. I noticed my eyes going down on me when they left me undiagnosed with B12 so long, it made me have uveitis/inflammation of the eyes. Right one being the worst and that is where the cataract is.
My consultant seems to think it is very common with people with diabetes. I have been diagnosed pre-diabetic, but only had this problem since I went on T3. I asked my consultant could T3 cause diabetes but he said no. I am not so sure.
Someone further up mentioned the sun, I know that this theory has been going around a long time. But to tell me our sun that gives us life and we have been under it for 1000's of years suddenly starts to cause cataracts. I just do not buy that one.
I do not want the op and have been putting NAC eyedrops in my eyes 3 times a week to see if that will make any difference, and start to dissolve the cataract. I only started 2 weeks ago. A uphill battle I know as my cataract is not in the usual place, front of eye.
I have often wondered if levothyroxine maybe the culprit. But cannot find a lot on it when I research.
Interesting. I had cataracts removed from both eyes last year when I was 58. I was told I was young to have them. I was diagnosed with hypothyroidism this year finally after years of feeling unwell.
I too have had cataracts develop in both eyes, right worse than left, since starting Levothyroxine in 2022, optician says cataract not bad enough yet for surgery. From research I have read it seems that they are very much on the increase everywhere and it’s thought to be due to multiple factors in our environment (toxins, dietary factors, less sleep) causing an onslaught of stress generally to our bodies.
I had cataract surgery a couple of years ago in one eye. Seen as young to have a cataract. The other eye now has a cataract developing. I have had untreated hypothyroidism for over a decade - possibly two decades.
The last time I had my eyes tested I was told (for the first time) that I was developing cataracts. It isn't a surprise. My mother had them but was never given treatment for them - and she was hypothyroid. By the time she died in her 80s she couldn't read without enormous difficulty.
I seem to be following in my mother's footsteps with regard to many aspects of my health. I just hope I don't live as long as she did with her enormous list of health problems.
My father had thyroid disease (Hyper) & cataracts in both eyes. I also have autoimmune thyroid disease (Hypo) & have cataracts in both eyes. I have always worn sunglasses when out so I definitely believe that there is a link between thyroid disease & cataracts.... along with the various other conditions that the medical profession fail to acknowledge or treat accordingly.
An interesting link, thanks for posting it! I had cataracts operated on two years ago - it's a wonderful surgery for anyone needing it, quick and so effective. In my 60s, I was 20 years younger than my mother was when she had them. She doesn't have a thyroid condition. I don't know of anyone else in my family who had them or had a thyroid condition either. My husband had surgery for them in his late 60s and he doesn't have a thyroid problem but his mother had similar eye problems.
I assumed mine were due to taking hydrocortisone for adrenal problems 15 years ago, but perhaps not. I do know that eyes react to different doses of thyroid hormone, and it seemed in some threads that vitreous detachments were linked with low levels of hormones.
For anyone facing cataract surgery who can afford to pay privately (about £4500 for both eyes), if you also have astigmatism you can have lenses fitted to correct that. I now see better than since I was in school and don't need contacts any more, just +1 reading glasses bought over the counter. If you don't have astigmatism and don't need special lenses then the NHS surgery is as good.
I've heard the same, and I also feel there's a bit of a conspiracy about when to operate! My optician, who only told me I had cataracts when I asked him directly, tried to dissuade me from surgery because he said it was very dangerous, had a high failure rate, and I could probably manage for another few years without it. I am the family driver and was having difficulties at night, so I insisted he refer me, and was told by the surgeon about three weeks later that my right eye was verging on illegal for driving. The surgery is so wonderful, and makes such a huge difference, that I think it's appalling that people are being made to wait. In 2022 (or 2023?) cataract surgery was carried out in the evenings and weekends in some areas, to clear the backlog of patients, and if they could work over those hours then, I wish they could do it routinely! I also think there are probably a lot of people in need of the surgery who are being allowed to drive, when they are actually a great danger on the roads.
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