This Article Full Text Full Text (PDF) Submit a related Letter to the Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Walsh, J. P. Articles by Michelangeli, V. Search for Related Content PubMed PubMed Citation Articles by Walsh, J. P. Articles by Michelangeli, V. Related Collections Thyroid Female Endocrinology

Parity and the Risk of Autoimmune Thyroid Disease: A Community-Based Study

Department of Endocrinology and Diabetes (J.P.W.), Sir Charles Gairdner Hospital, Perth, Western Australia 6009, Australia; Schools of Medicine and Pharmacology (J.P.W., P.J.L.), Population Health (A.P.B., M.K.B.), and Women’s and Infants’ Health (P.O.), University of Western Australia, Western Australia 6009, Australia; Genomics Directorate (P.O.), Department of Health, Western Australia 6009, Australia; Laboratory for Cancer Medicine (P.J.L.), University of Western Australia Centre for Medical Research, Western Australian Institute for Medical Research, Perth, Western Australia 6000, Australia; Department of Endocrinology and Diabetes (P.J.L.), Royal Perth Hospital, Perth, Western Australia 6000, Australia; and Biomediq-DPC (P.F., V.M.), Doncaster, Victoria 3108, Australia

Address all correspondence and requests for reprints to: Dr. John P. Walsh, Department of Endocrinology and Diabetes, Sir Charles Gairdner Hospital, Nedlands, Western Australia 6009, Australia. E-mail: john.walsh{at}health.wa.gov.au.

Context: Recent studies have suggested that fetal microchimerism (transplacental passage of fetal cells followed by engraftment into maternal tissues) may play a role in the pathogenesis of autoimmune thyroid disease. If that is true, then parity should be a risk factor for autoimmune thyroid disease.

Objective: The objective of this study was to examine parity as a risk factor for autoimmune thyroid disease.

Design, Setting, and Participants: TSH, thyroid peroxidase antibody, and thyroglobulin antibody concentrations were measured on archived sera from 1045 female participants in a 1981 community health survey in Busselton, Western Australia.

Outcome Measures: Odds ratios (ORs) for positive thyroid antibodies (increased concentration of either antibody) or thyroid dysfunction (abnormal serum TSH) were used.

Results: After adjustment for age, women who had previously been pregnant did not have a significantly increased risk of positive thyroid antibodies [OR, 1.20; 95% confidence interval (CI), 0.74–1.97; P = 0.46], raised TSH (OR, 0.93; 95% CI, 0.46–1.87; P = 0.84), or reduced TSH (OR, 0.87; 95% CI, 0.33–2.30; P = 0.79) compared with women who had never been pregnant. For each additional pregnancy, the OR was 1.02 (95% CI, 0.94–1.11; P = 0.57) for positive antibodies, 1.02 (95% CI, 0.91–1.14; P = 0.67) for raised TSH, and 1.03 (95% CI, 0.87–1.22; P = 0.73) for reduced TSH. Analysis using number of live births gave similar results. The results were similar in younger and older women.

Conclusions: Parity is not a risk factor for thyroid autoimmunity or thyroid dysfunction. These data do not support a key pathogenic role for fetal microchimerism in chronic autoimmune thyroid disease.

This article has been cited by other articles:

				T. H. Brix, P. S. Hansen, K. O. Kyvik, and L. Hegedus Aggregation of Thyroid Autoantibodies in Twins from Opposite-Sex Pairs Suggests that Microchimerism May Play a Role in the Early Stages of Thyroid Autoimmunity J. Clin. Endocrinol. Metab., November 1, 2009; 94(11): 4439 - 4443. [Abstract] [Full Text] [PDF]

				H. Volzke, T. Ittermann, C. O Schmidt, M. Dorr, U. John, H. Wallaschofski, B. H C Stricker, S. B Felix, and R. Rettig Subclinical hyperthyroidism and blood pressure in a population-based prospective cohort study Eur. J. Endocrinol., October 1, 2009; 161(4): 615 - 621. [Abstract] [Full Text] [PDF]

				M. Klintschar, U.-D. Immel, A. Kehlen, P. Schwaiger, T. Mustafa, S. Mannweiler, S. Regauer, M. Kleiber, and C. Hoang-Vu Fetal microchimerism in Hashimoto's thyroiditis: a quantitative approach Eur. J. Endocrinol., February 1, 2006; 154(2): 237 - 241. [Abstract] [Full Text] [PDF]