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

A nationwide Danish register-based study

Marianne Thvilum, Frans Hjelm Brandt Kristensen, Thomas Heiberg Brix, Laszlo Hegedüs

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

Resumé

BACKGROUND: 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.

METHOD: 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.

RESULTS: 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).

CONCLUSION: 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.

OriginalsprogEngelsk
TidsskriftClinical Endocrinology
Vol/bind87
Udgave nummer6
Sider (fra-til)832-837
ISSN0300-0664
DOI
StatusUdgivet - 2017

Fingeraftryk

Cohort Studies
Confidence Intervals
Environmental Exposure
Autoimmunity
Proportional Hazards Models
Autoimmune Hypothyroidism
Diabetes Mellitus
Incidence
Health

Citer dette

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title = "Month of birth is associated with the subsequent diagnosis of autoimmune hypothyroidism: A nationwide Danish register-based study",
abstract = "BACKGROUND: 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.METHOD: 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.RESULTS: 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).CONCLUSION: 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.",
keywords = "Journal Article",
author = "Marianne Thvilum and {Hjelm Brandt Kristensen}, Frans and Brix, {Thomas Heiberg} and Laszlo Heged{\"u}s",
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year = "2017",
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Month of birth is associated with the subsequent diagnosis of autoimmune hypothyroidism : A nationwide Danish register-based study. / Thvilum, Marianne; Hjelm Brandt Kristensen, Frans; Brix, Thomas Heiberg; Hegedüs, Laszlo.

I: Clinical Endocrinology, Bind 87, Nr. 6, 2017, s. 832-837.

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

TY - JOUR

T1 - Month of birth is associated with the subsequent diagnosis of autoimmune hypothyroidism

T2 - A nationwide Danish register-based study

AU - Thvilum, Marianne

AU - Hjelm Brandt Kristensen, Frans

AU - Brix, Thomas Heiberg

AU - Hegedüs, Laszlo

N1 - This article is protected by copyright. All rights reserved.

PY - 2017

Y1 - 2017

N2 - BACKGROUND: 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.METHOD: 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.RESULTS: 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).CONCLUSION: 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.

AB - BACKGROUND: 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.METHOD: 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.RESULTS: 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).CONCLUSION: 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.

KW - Journal Article

U2 - 10.1111/cen.13425

DO - 10.1111/cen.13425

M3 - Journal article

VL - 87

SP - 832

EP - 837

JO - Clinical Endocrinology

JF - Clinical Endocrinology

SN - 0300-0664

IS - 6

ER -