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Journal of Thyroid Research
Volume 2010, Article ID 101948, 5 pages
http://dx.doi.org/10.4061/2010/101948
Research Article

Increasing Incidence, but Lack of Seasonality, of Elevated TSH Levels, on Newborn Screening, in the North of England

1Institute of Health and Society, Newcastle University, Newcastle upon Tyne NE1 4LP, UK
2Department of Paediatrics, Royal Victoria Infirmary, Newcastle upon Tyne NE1 4LP, UK
3Department of Biochemistry, University Hospital of North Durham, Durham DH1 5TW, UK
4Department of Clinical Biochemistry, Royal Victoria Infirmary, Newcastle upon Tyne NE1 4LP, UK
5Department of Microbiology, University Hospital of North Durham, Durham DH1 5TW, UK
6Department of Paediatrics, James Cook University Hospital, Middlesbrough TS3 3TA, UK

Received 3 June 2009; Accepted 15 December 2009

Academic Editor: Jack R. Wall

Copyright © 2010 Mark S. Pearce et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Previous studies of congenital hypothyroidism have suggested an increasing incidence and seasonal variation in incidence, which may suggest nongenetic factors involved in aetiology. This study describes the incidence of elevated thyroid stimulating hormone (TSH) values in newborns, a surrogate for congenital hypothyroidism, measured as part of the screening programme for congenital hypothyroidism, over an eleven-year period (1994–2005), and assesses whether seasonal variation exists. All infants born in the Northern Region of England are screened by measuring levels of circulating TSH using a blood spot assay. Data on all 213 cases born from 1994 to 2005 inclusive were available. Annual incidence increased significantly from 37 per 100,000 in 1994 to a peak of 92.8 per 100,000 in 2003. There was no evidence of seasonal variation in incidence. The reasons for the increasing incidence are unclear, but do not appear to involve increasing exposure to seasonally varying factors or changes in measurements methods.