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Seasonal variation of neonatal transient hyperthyrotropinemia in tehran province, 1998–2005
Endocrine Research Center, Taleghani Hospital, Shaheed Beheshti University of Medical Sciences, Tehran, Iran.
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2010 (English)In: Chronobiology International, ISSN 0742-0528, E-ISSN 1525-6073, Vol. 27, no 9-10, 1854-1869 p.Article in journal (Refereed) Published
Abstract [en]

Seasonal aggregation and the monthly rate of neonatal transient hyperthyrotropinemia(THT) were assessed. From November 1998 to April 2005, neonates of gestationalage ≥37 wks, birth weight 2500–4000 g, birth length 45–55 cm, and 1st min Apgarscore >3, who had thyrotropin (TSH) ≥20 mU/L in their cord dried-blood specimen,but without congenital hypothyroidism, were enrolled in the study. The recall rateequals the rate of THT occurrence in this study. Of 47,945 neonates, 555 had THT(recall rate: 1.2%). The aggregated seasonal recall rate (recall for further assessment torule out congenital hypothyroidism) was significantly higher in winter (January,February, and March) than the other seasons ( p < .0001). Winter had higher recallrate in each year as compared to other seasons, but the overall rate of recalls decreasedin 2001 and 2002. Excluding the first 6 months (due to erratic variations), the remaining72 months revealed a relatively sinusoidal pattern in monthly recall rates; indeed,there was an initial 11-month high recall rates (1.7%), followed by a 33-month decrease(0.7%), a 19-month increase (1.9%), and a final 9-month decrease (0.8%). The recallrate of each of these time intervals was significantly different from that of the nexttime interval ( p < .0001). The monthly recall rates were best fitted to cubic curve estimationand then autoregressive integrated moving average (ARIMA) (0, 1, 1) models.THT occurs significantly more in winter than in other seasons, and this suggests apossible role for time-varying factor(s) contributing to its seasonal preponderance.

Place, publisher, year, edition, pages
Informa Healthcare, 2010. Vol. 27, no 9-10, 1854-1869 p.
Keyword [en]
Cord blood, Neonates Newborn screening, Recall rate, Seasonality, Thyrotropin
National Category
Medical and Health Sciences
Research subject
URN: urn:nbn:se:umu:diva-59592DOI: 10.3109/07420528.2010.516046OAI: diva2:553282
Available from: 2012-09-21 Created: 2012-09-18 Last updated: 2012-11-29Bibliographically approved

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Padyab, Mojgan
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