The evaluation of risk factors and screening test in newborns diagnosed with congenital hypothyroidism within newborn screening program in ankara in 2009: a nested case-control study

Congenital Hypothyroidism (CH) is a common preventable endocrinological disease in newborns all over the world and for this reason it has been a significant public health problem.The aim of this study is to evaluate the risk factors leading to CH and to determine the appropriateness of the cut-off value used in screening in our country.To investigate the risk factors, mothers of 84 newborns diagnosed with CH and 188 normal newborns as control group out of newborns whose dry blood spots were collected in National Newborn Screening Program (NSP) in Ankara in 2009 were enrolled a survey to perform a nested case-control study. In the survey, the parameters belonged to mother were mother age, education level, consanguineous marriage, smoking, alcohol use and radiation exposure during pregnancy, parity, history of abortus and still birth. Parameters related to the newborn were birth weight, singleton/multiple pregnancy, gestational age, delivery method. In addition, the presence of thyroid diseases (goiter, hypothyroidism) in family members was other parameter too.When family parameters evaluated, a statistically significant association with consanguineous marriage, history of threatened abortion, presence of thyroid disease or CH in family members was observed in newborns with CH.The second component of our study is related to the strength of screening test. When the cut-off value was taken as 15.05 mlU/L in the analysis of dry blood spots taken ?between 2-6 days after birth? using the test for CH in screening laboratories in our country, sensitivity and specificity of test was observed as 77.1% and 97.3%, respectively. This supports the appropriateness of the current cut-off value defined as ?15 mlU/L? for our country used in NSP workflow.Risk factors observed in this study and definition of the cut-off value as 15.05 mU/L in screening test are highly significant in establishing health policies for NSP in our country.