Month of birth is associated with the subsequent diagnosis of autoimmune hypothyroidism

Do you have autoimmune thyroid disease? In what month were you born?

(I assume that the months would be shifted by 6 in the southern hemisphere. :-) )

Clin Endocrinol (Oxf). 2017 Jul 20. doi: 10.1111/cen.13425. [Epub ahead of print]

Month of birth is associated with the subsequent diagnosis of autoimmune hypothyroidism. A nationwide Danish register-based study.

Thvilum M1, Brandt F2, Brix TH1, Hegedüs L1 .

Author information:

1 Department of Endocrinology and Metabolism, Odense University Hospital, Denmark. Kloevervaenget 10, 6th floor, 5000, Denmark.

2 Department of Internal Medicine, Hospital of Southern Denmark, Sydvang 1, 6400, Sonderborg, Denmark.



The triggering of thyroid autoimmunity in the genetically susceptible remains a conundrum. Environmental exposures during gestation and/or early postnatally have proponents, as suggested in diabetes mellitus, with a higher incidence of births during spring and summer. Whether the development of autoimmune hypothyroidism (AIT) is influenced by month or season of birth is less clear.


Nationwide cohort study of 111,565 individuals diagnosed with AIT and four euthyroid controls per case, matched according to age and sex, were identified from Danish health registers. Differences in month-of-birth across the year was evaluated by the Walter-Elwood test. The risk of AIT patients being born in a certain month or season of the year was calculated using a Cox regression model.


There was a significant difference in birth month between cases and controls, p<0.001. Individuals with AIT had a significantly increased risk of being born in June (Hazard ratio 1.04; 95% Confidence interval (CI): 1.02-1.08) and in the summer (June-August; HR 1.02; 95%CI: 1.01-1.04).


In this large-scale nationwide cohort study, we found a higher risk of AIT when born in the summer season or more specifically in June, supporting the hypothesis that seasonal variations in exposures - gestationally and/or early postnatally - may contribute to the development of AIT. This article is protected by copyright. All rights reserved.

PMID: 28727153

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69 Replies

  • I was born in september!

  • So was my mother and she has both diabetes 2 and Parkersons disease!

  • Born in March

  • Me, too. :)

  • I was born in June!

  • I'm the 29th june

  • I was born in October.

  • May (although diagnosed with Graves, i.e. a hyper autoimmune if that counts??)

  • February

  • Me too.February 25 and I had a thyroid goitre that nearly killed me.Plus under hypthroidism before it was removed. I am on thyroxine for the rest of my life as a result.

  • Me too febuary

    Daughter December

    Mum may

    Dad January

    Niece April

    Cousin febuary

    Gran febuary

  • I was born in January

  • I was end of April, my husband was end of January. We both have Hashimoto's. I worry about my 9 year old daughter (born end of May). She always seems tired and gets pins & needles a lot but hopefully I'm just being paranoid.

  • Check your daughters levels of B12 - Folate - Ferritin - VitD - from what I see with 5 grandchildren modern food does not always supply the best nutrients. Pins and needles can be linked to low B12 ....

  • Thank you v much Marz- that's a good place to start.

  • Easily resolved too - come back here with results in a new post and people will help :-)

  • July! 😲

  • June!!!

  • March, January and September for my immediate family with an August hyperthyroid annomaly! Exceptions that probe the rule 😊

    A pole of this would be fun!

  • Hi i did suffer from this 3 years ago thyroid under control now I was born in February but last week I just got diagnosed with osteoporosis and Osteoarthritis and checking online thyroid trouble is up there with these they are all linked xx

  • August !

  • September and April for these two Hashimotos bods :-)

  • June

  • June

  • February for me

  • My two sisters were born in August and I was born in July. My niece was born in September, and my cousin was born in May. We all have autoimmune problems.

  • I guess genetic plays a bigger role than wich month you see the world for the first time..

  • Yes maybe it's certainly complicated. I was adopted and never meet my two sister until I was in my forties.

  • June

  • August

  • I'm June and have Hashimoto's. My bro is August and has type 1 diabetes. Neither of our parents have autoimmune issues!

  • Im a December baby!!🎄

    My mom however was born in June & no AIT or hypo .... Hmm

  • November, does'nt save me.

  • August for me with hashimotos. My sister born in April has rheumatoid arthritis (autoimmune)

  • I was born in June and have autoimmune kidney disease but my thyroid issues are due to having hemilobectomy

  • January... brother born in June and perfectly healthy.

  • Two aunties with hypothyroidism- one June (I think... she's a cancer) and the other Christmas Day.

  • I was born in June, sister with hashis born in april

  • I was born in December, my husband September and my my mum October. We are all hypo.

  • I was born in June and have Hashis.

  • December baby with Hashi's... So that puts that one to bed then, although I seem to be in a clear minority!

  • April and have Hashimoto.

  • I was born in October

  • Early July with Hashi's

  • January

  • I was born in July and my son was born in September.

  • October for me, November for my son, December for my husband (no auto-immune), June for daughter (no auto-immune) and July for eldest son who has symptoms but is denying it.

  • Hypothesis 1:

    Vitamin D???

    Possible Cause:

    Daylight hours are significantly different from winter to summer and seasonal diet (more fish in the summer) in Denmark where the study was done.

    Well it's worth looking into - wonder if there are other nutrients with seasonal variations..?

    Hypothesis 2:

    Mineral / vitamin content of animal products???

    Possible Cause:

    Dairy and meat can certainly vary in its quality across the year at these latitudes - grass fed in summer, grain fed in winter.


    We've got a mixed bag of birth months in our family and autoimmune / allergy illnesses across the board, so I doubt it's statistically helpful.

  • I was born in June.

  • I'm December with hashimotos!

  • I was born in April 1984. My doctor said my graves disease was a result of child birth. There is no history of thyroid problems in my family although my mum had part of her calcium gland, removed because it was producing too much calcium. The symptoms are quite similar to that of graves disease.

  • Should also add, all female relatives from my paternal have autoimmune thyroid disease. My three children all have symptoms but no diagnosis.

  • I was born in November and so was my Sister

  • November for me. xx

  • November for me. Can't wait to tell my June born daughter-she will accuse me of making it up-she is in denial! 😂

  • Born in july

  • January

  • I'm hypo - born end of August.

  • I was born in March

  • June

  • November hashies

  • June for me too!

    My nan and grandma and cousins and aunties as well- all June babies and all with hashimotos

  • I was born in June, my sister who also has thyroid problems was born in December.

  • I'm an October hypo, hubby is an insulin dependant diabetic born in February.

  • April both me with hashimoto and my brother with crohnes

  • I'm going to go one further and say that it is looking like to me from the majority of answers to be more common with people from the cardinal signs cancer, Capricorn, aries and libra. I would think there would be a lot of virgos here too september, because Virgo rules the 6th house of health. There is a whole branch of astrology dedicated to medicine and health and I have personally found it to be very accurate for me. It goes right into cell salts and how the affects of transits can manifest in our health. I really like lyn koiners recommendations. She teaches medical astrology and has a lot of Information online. It's a s fascinating topic

  • yep, I'm a Libra, born in October

  • I'm actually a Scorpio as born 27th October so I 'm not sure how that stacks up? I have multiple problems at present and though I can relate to lots of what I have read I'm also pretty confused about what is causing what. I'm so sorry, this is confusing for anyone so I will try to explain, I've been hypothyroid for a long time (years) & been taking 150Mcg thyroxine since day one, I can't remember when I last had a blood test & haven't a clue about all the different tests though when I read about gall bladder probs (had to have mine out) & tiredness (I have days which are 'cancelled') but I am also recovering from radio therapy and chemotherapy, going into the day surgery unit for facet joint jabs for osteoarthritis on 10th August, back at the dentist to get false teeth altered on Weds 2 nd August as still living on fortisip & want to eat and being driven crazy with both tinnitus & what I'm told is lymphatic tissue at the front of my neck which, some days makes me feel like a freak! Gosh, I am sorry for this outpouring but it's the first time I have actually said it (there is more but I think I have said enough for now). If anyone has some good but simple advice I would love to hear.........

  • I suggest you click on the green [ Write a post ] and put whatever you want help with there. That way, far more people will see it, and reply. :-) It sounds like you need some support and many here will be happy to help as far as we can.

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