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Neonatal Thyroid-Stimulating Hormone Screening as a Monitoring Tool for Iodine Deficiency in Turkey
Nilgün Çaylan1, Başak Tezel, Sema Özbaş
1Public Health Institution of Turkey, Department of Child and Adolescent Health, Ankara, Turkey Phone: +90 312 565 60 76
Insights
Neonatal screening indicates mild iodine deficiency in Turkey, with elevated thyroid-stimulating hormone (TSH) levels observed in 7.2% of newborns. Further nationwide studies are recommended to confirm iodine status.
Area of Science:
- Endocrinology
- Public Health
- Pediatrics
Background:
- Thyroid-stimulating hormone (TSH) levels in newborns serve as a key indicator for assessing population-level iodine deficiency (ID) and monitoring iodine supplementation programs.
- The National Newborn Screening Program (NNSP) for congenital hypothyroidism (CH) collects crucial data for public health surveillance.
Purpose of the Study:
- To analyze neonatal TSH levels from the 2014 NNSP data to predict the current iodine nutrition status in Turkey.
- To identify regional and seasonal variations in elevated TSH levels as indicators of potential iodine deficiency.
Main Methods:
- Utilized heel-prick blood samples from newborns collected on filter paper cards, analyzing results from samples obtained >48 hours post-birth.
- Assessed the severity of iodine deficiency using World Health Organization (WHO) epidemiologic criteria.
- Classified elevated TSH levels (>5 mIU/L) based on province, region, birth season, and sampling time.
Main Results:
- A total of 1,270,311 newborns' screening results were included in the analysis.
- The national prevalence of elevated TSH was 7.2%.
- Significant regional variations were observed, with the highest TSH elevation rate in Gaziantep (15.9%) and the lowest in Tekirdağ (4.0%). Seasonal analysis showed the highest prevalence in winter (7.4%).
Conclusions:
- Neonatal CH screening results suggest that Turkey may be experiencing mild iodine deficiency.
- Further nationwide studies are essential for a direct assessment and accurate monitoring of iodine status in vulnerable populations.
Objective:
Thyroid-stimulating hormone (TSH) level in neonates is recommended as an indicator for presence of iodine deficiency (ID) at a population level and as a monitoring tool in programs of iodine supplementation. The purpose of this study, based on data from the National Newborn Screening Program (NNSP) for congenital hypothyroidism (CH) in 2014, was to analyze neonatal TSH levels to predict the current status of iodine nutrition in Turkey.
Methods:
According to screening methodology, heel-prick blood samples of newborns were collected on filter paper cards usually on day 3-5 after birth (or shortly before discharge). Results of samples collected >48 h after birth were analyzed. The degree of severity of ID was assessed by using the epidemiologic criteria of the World Health Organization (WHO). Elevated TSH levels (>5 mIU/L) were processed and classified according to province, region, birth season, and sampling time.
Results:
A total of 1,298531 newborns were registered in the NNSP for the CH database. Of those, 1,270311 newborns had screening results collected >48 h after birth and were included in the statistical analyses. The national prevalence of elevated TSH was 7.2%. While the Gaziantep sub-region had the highest TSH elevation rate (15.9%), the Tekirdağ sub-region had the lowest rate (4.0%; p<0.001). Seasonal variations were also significant, and the elevated TSH prevalence rate was highest in winter (7.4%; p<0.001).
Conclusion:
National CH screening results suggest that Turkey may still be mildly iodine deficient. Nationwide studies should be performed for direct assessment and monitoring of iodine status in vulnerable populations to confirm accuracy of our results.
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