Regional Variation in the Incidence of Congenital Hypothyroidism in Macedonia.

Milica Pesevska,Elizabeta Taseva,Elena Sukarova-Angelovska,Violeta Anastasovska,Mirjana Kocova

doi:10.3390/ijns3030022

Milica Pesevska, Elizabeta Taseva + Show 3 more

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https://doi.org/10.3390/ijns3030022

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Abstract

The incidence of congenital hypothyroidism (CH) is increasing in different areas around the world. Potential causes include changes in population ethnic composition, environmental factors, changing screening program methodology and lowering of TSH cutoff levels. The incidence of CH in different regions of Macedonia has not been evaluated before. A total of 251,008 newborns from all eight regions in the country have been screened between 2002 and 2015, by measurement of the thyroid-stimulating hormone (TSH) from blood spots, sampled 48-72 h after birth, using the DELFIA assay. Overall CH incidence confirmed at birth was 1/1976. The highest CH incidence was observed in the Vardar region (1/970), while the Eastern region had the lowest incidence (1/4202; p=0.021). In the other regions, the following CH incidence was detected: Northeastern 1/1459, Pelagonia 1/1627, Polog 1/1444, Skopje 1/2430, Southwestern 1/3226, and Southeastern 1/1843. Interestingly, in the Vardar region, 4.44% of the screened newborns had a TSH concentration > 5 mIU/L, as an indicator of regional iodine deficiency, compared to the Eastern region where 1.66% of newborns had a TSH > 5 mIU/L. The higher CH incidence in some of the regions may be due to increasing exposure to environmental toxic agents and/or deficient iodine intake. Further research into the potential environmental determinants of increased CH risk is warranted.

Highlights

Congenital hypothyroidism (CH) is a clinical condition caused by decreased production or inadequate action of thyroid hormones, resulting in a reduction of metabolic processes and impaired neurodevelopment
The highest CH incidence of 1/970 was detected in the Vardar region, while the lowest CH incidence of 1/4202 was observed in the Eastern region (Figure 1)
There was a significant difference between the CH incidence in Vardar and the Southwestern region (1/3226), (p = 0.052; x2 = 3.77)

Summary

Introduction

Congenital hypothyroidism (CH) is a clinical condition caused by decreased production or inadequate action of thyroid hormones, resulting in a reduction of metabolic processes and impaired neurodevelopment. According to the world-wide data obtained from neonatal thyroid screening programs, the incidence of primary CH is approximately 1:3000 to 1:4000. Despite similarity in the risk factors for CH in different countries such as female gender, birth defects, twins, preterm deliveries, geographic location, ethnicity, iodine deficiency, etc., the currently reported CH incidence varies widely worldwide [1,2,3]. The differences in CH incidence have mostly been attributed to the change of screening procedures, and the reduction of cutoff levels [5,6]. Differences of CH incidence are more likely due to iodine deficiency or to the type of screening method than to ethnic affiliation [10]

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