Development of Autoimmune Overt Hypothyroidism Is Highly Associated With Live Births and Induced Abortions but Only in Premenopausal Women

TY - JOUR

T1 - Development of Autoimmune Overt Hypothyroidism Is Highly Associated With Live Births and Induced Abortions but Only in Premenopausal Women

AU - Carlé, Allan

AU - Pedersen, Inge Bülow

AU - Knudsen, Nils

AU - Perrild, Hans

AU - Ovesen, Lars

AU - Rasmussen, Lone Banke

AU - Laurberg, Peter

PY - 2014/6

Y1 - 2014/6

N2 - CONTEXT: The 1-year postpartum period is often accompanied by increased risk for thyroid disease.OBJECTIVE: The objective of the study was to investigate the role of reproductive risk factors in the development of autoimmune overt hypothyroidism in the years after the 1-year postpartum period.DESIGN, SETTING, AND SUBJECTS: In a population study, we included Danish women with new autoimmune overt hypothyroidism not diagnosed within the first year after a pregnancy (n = 117; median age 53.0 y) and age- and region-matched euthyroid controls from the same population (n = 468).MAIN OUTCOME MEASURES: In conditional multivariate logistic regression models, we analyzed the associations between the development of autoimmune hypothyroidism and age at menarche/menopause, years of menstruations, pregnancies, spontaneous and induced abortions, live births, and years on oral contraceptives and postmenopausal hormone replacement therapy, also taking various possible confounders into account.RESULTS: In multivariate regression models with no event as reference, the odds ratios (ORs) for hypothyroidism [95% confidence interval (CI)] after one/two/three or more live births were 1.72 (0.56-5.32)/3.12 (1.14-8.48)/4.51 (1.65-12.3) and 1.02 (0.57-1.81)/2.70 (1.27-5.75) after one/two or more induced abortions. Findings were valid only for women having hypothyroidism diagnosed before the age of 55 years. We found no association between disease development and other reproductive risk factors investigated.CONCLUSIONS: Previous live births and induced abortions were major risk factors for the development of autoimmune overt hypothyroidism in women aged up to 55 years. The increased risk for hypothyroidism after giving birth extends longer than just to the 1-year postpartum period, and numbers of previous pregnancies should be taken into account when evaluating the risk of hypothyroidism in a young women.

AB - CONTEXT: The 1-year postpartum period is often accompanied by increased risk for thyroid disease.OBJECTIVE: The objective of the study was to investigate the role of reproductive risk factors in the development of autoimmune overt hypothyroidism in the years after the 1-year postpartum period.DESIGN, SETTING, AND SUBJECTS: In a population study, we included Danish women with new autoimmune overt hypothyroidism not diagnosed within the first year after a pregnancy (n = 117; median age 53.0 y) and age- and region-matched euthyroid controls from the same population (n = 468).MAIN OUTCOME MEASURES: In conditional multivariate logistic regression models, we analyzed the associations between the development of autoimmune hypothyroidism and age at menarche/menopause, years of menstruations, pregnancies, spontaneous and induced abortions, live births, and years on oral contraceptives and postmenopausal hormone replacement therapy, also taking various possible confounders into account.RESULTS: In multivariate regression models with no event as reference, the odds ratios (ORs) for hypothyroidism [95% confidence interval (CI)] after one/two/three or more live births were 1.72 (0.56-5.32)/3.12 (1.14-8.48)/4.51 (1.65-12.3) and 1.02 (0.57-1.81)/2.70 (1.27-5.75) after one/two or more induced abortions. Findings were valid only for women having hypothyroidism diagnosed before the age of 55 years. We found no association between disease development and other reproductive risk factors investigated.CONCLUSIONS: Previous live births and induced abortions were major risk factors for the development of autoimmune overt hypothyroidism in women aged up to 55 years. The increased risk for hypothyroidism after giving birth extends longer than just to the 1-year postpartum period, and numbers of previous pregnancies should be taken into account when evaluating the risk of hypothyroidism in a young women.

KW - Abortion, Induced

KW - Adolescent

KW - Adult

KW - Aged

KW - Case-Control Studies

KW - Cross-Sectional Studies

KW - Denmark

KW - Female

KW - Hashimoto Disease

KW - Humans

KW - Infant, Newborn

KW - Live Birth

KW - Middle Aged

KW - Pregnancy

KW - Premenopause

KW - Risk Factors

KW - Young Adult

U2 - 10.1210/jc.2013-4474

DO - 10.1210/jc.2013-4474

M3 - Journal article

C2 - 24694338

SN - 0013-7227

VL - 99

SP - 2241

EP - 2249

JO - Journal of Clinical Endocrinology and Metabolism

JF - Journal of Clinical Endocrinology and Metabolism

IS - 6

ER -