Newborn Screening for Thyroid-stimulating Hormone as an Indicator for Assessment of Iodine Status in the Republic of Macedonia

Iodine deficiency is associated with goiter and impaired brain function leading to cretinism. An increased frequency of thyroid-stimulating hormone (TSH) measurements above 5 mlU/L on newborn screening points toward an impaired iodine status of the population.A 13-year retrospective analysis was performed in 228,266 newborns participating in the national thyroid newborn screening program. The TSH concentration was measured in dry blood spots collected by heel stick on filter paper, 48 hours after birth, using fluoroimmunometric DELFIA method.Out of 236,378 live-born infants, 228,266 (96.6%) have been screened for TSH, of which 198,213 (86.8%) were retrospectively evaluated for TSH levels above 5 mlU/L. Neonates with congenital hypothyroidism, prematurity, and low birth weight were excluded from the evaluation, as well as the inadequately sampled neonates (13.2%). A national prevalence of 3.08% newborns (n=6,105) with TSH5 mIU/L was found. Higher percentages were noted in two regions of the country, indicating possible mild iodine deficiency in these regions and shifting the overall average to above 3%.Our results indicate overall iodine sufficiency in the Macedonian population. Additional assessment of the iodine intake in the regions with suspected mild iodine deficiency is needed to prevent suboptimal cognitive and psychomotor outcomes.Nedostatak joda je povezan sa strumom i kompromitovanom funkcijom mozga sa konsekutivnim kretenizmom. Povecćana učestalost nivoa tireostimulišućeg hormona (TSH) iznad 5 mU/L dobijena na skriningu novorolenih govori o poremecenom statusu joda u stanovništva.Uralena je retrospektivna analiza kod 228,266 no- vorolenčadi koja su tokom proteklih 13 godina bila obuhvaćena nacionalnim neonatalnim tiroidnim skrining programom. Koncentracija TSH je merena u suvim kapima krvi pokupljene iz pete novorolencadi na filter hartiji, 48časova nakon rolenja, koristeći fluoroimunometrijsku DELFIA metodu.Od 236,378 živorodenih, 228,266 (96,6%) testi- rani su za TSH, od kojih su 198,213 (86,8%) retrospek-tivno analizirani za nivo TSH iznad 5 mU/L. Novorolencčad sa urolenom hipotireozom, preranim rolenjem i niskom porolajnom tezinom, kao i novorolencad sa neadekvatno sakupljenim uzorcima krvi (13,2%) isključena su iz pro - cene. Dobijena je nacionalna prevalencija od 3,08% novorolenčadi (n=6,106) sa TSH5 mU/L. Veći procenat od prosečnog je zabeležen u dva regiona u zemlji, ukazujući namoguć blagi nedostatak joda u ovim regionima.Naži rezultati ukazuju na sveukupnu dovoljnost joda kod makedonskog stanovništva. Dodatna procena unosa joda u regionima sa sumnjom na blagi nedostatak joda je potrebna da bi se omogucio normalan kognitivni i psihomotorni razvoj kod dece.