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The increased incidence of congenital hypothyroidism: fact or fancy
Lee Lab
  • Marvin L. Mitchell, University of Massachusetts Medical School
  • Ho-Wen Hsu, University of Massachusetts Medical School
  • Inderneel Sahai, University of Massachusetts Medical School
  • Stuart J. Brink, Tufts University
  • Rosalind S. Brown, University of Massachusetts Medical School
  • Laurie E. Cohen, New England Newborn Screening Program
  • Roger B. Eaton, University of Massachusetts Medical School
  • Mary M. Lee, University of Massachusetts Medical School
  • Lynne L. Levitsky, New England Newborn Screening Program
  • Edward Reiter, New England Newborn Screening Program
  • Abdollah Sadeghi-Nejad, Tufts University
  • Leslie A. Soyka, University of Massachusetts Medical School
  • Joseph I. Wolfsdorf, Harvard Medical School
  • Bradford L. Therrell, New Engand Newborn Screening Program
UMMS Affiliation
Department of Pediatrics
Date
12-1-2011
Document Type
Article
Medical Subject Headings
Child; Cohort Studies; Congenital Hypothyroidism; Female; Follow-Up Studies; Humans; Incidence; Infant; Infant, Newborn; Male; Massachusetts; Neonatal Screening; Severity of Illness Index; Up-Regulation
Abstract

OBJECTIVE: The incidence of congenital hypothyroidism (CH) detected by newborn screening in the US has increased significantly since the early 1990s. We defined the characteristics associated with the increased incidence.

PATIENTS: A cohort of children with CH born during an earlier period of low incidence (1991-94) was compared with a cohort born during a later period when the incidence of CH had doubled (2001-04).

MEASUREMENTS: Screening was performed with T4 as the primary marker and thyroid stimulating hormone (TSH) on selected specimens. Follow-up on hypothyroid children determined whether they had permanent or transient hypothyroidism. Cases were classified based on laboratory results: initial TSH >/=100 mU/l was 'severe,' initial TSH /l but >/=20 mU/l was 'mild' and initial TSH /l with subsequent abnormal TSH was 'delayed'.

RESULTS: The overall incidence of CH almost doubled between the two time periods, from 1:3010 to 1:1660. Excess cases were found in the mild and delayed categories, with no increase in severe cases. The proportion of transient cases was <5% in severe cases, 40% in mild cases and 70% among delayed cases. There was no difference in the proportion of transient case between the two time periods. Modifications to the T4/TSH testing protocol between the two time periods resulted in substantially increased numbers of specimens in the younger cohort being selected for TSH testing in both initial and repeat specimens.

CONCLUSION: The rising incidence of CH in Massachusetts is confined to mild and delayed cases. Our findings suggest that this rise is attributable to enhanced detection rather than an absolute increase in numbers.

Rights and Permissions
Citation: Clin Endocrinol (Oxf). 2011 Dec;75(6):806-10. doi: 10.1111/j.1365-2265.2011.04128.x. Link to article on publisher's site
Related Resources
Link to Article in PubMed
PubMed ID
21623857
Citation Information
Marvin L. Mitchell, Ho-Wen Hsu, Inderneel Sahai, Stuart J. Brink, et al.. "The increased incidence of congenital hypothyroidism: fact or fancy" Vol. 75 Iss. 6 (2011) ISSN: 0300-0664 (Linking)
Available at: http://works.bepress.com/mary_lee/10/