Incidence Of Primary Congenital Hypothyroidism Research Articles

Incidence of primary congenital hypothyroidism over 24 years in Finland

BackgroundA rise in the incidence of congenital hypothyroidism (CH) has been reported worldwide. This nationwide study aimed to describe the secular trends and current incidence of CH in Finland.MethodsTwo independent study cohorts, a national and a regional, were collected from national registers and patient records. The national cohort represents all CH cases born in Finland between 1994 and 2017. Birth data, results of the screening test, and the incidence of CH were reviewed.ResultsBetween 1994 and 2017, 1,400,028 children were born in Finland. Of these children, 503 were diagnosed with primary CH (incidence 1:2783). Male-to-female sex ratio was 1:2.0. The nationwide incidence was 33 cases per 100,000 live births between 1994 and 1999, 38 cases per 100,000 live births between 2000 and 2005, 40 cases per 100,000 live births between 2006 and 2011, and 33 cases per 100,000 live births between 2012 and 2017. In the regional cohort (n = 139), the incidence of transient CH was 3.6%. The incidence of mild, moderate, and severe CH remained constant.ConclusionsIn Finland, the incidence of CH has not changed during the 24-year study period.ImpactAs opposed to recent reports worldwide, the incidence of congenital hypothyroidism has not changed between 1994 and 2017 in Finland.The proportions of mild, moderate, and severe congenital hypothyroidism did not change significantly over the study period.Lowering the TSH cut-off limit or increasing immigration did not affect the incidence rate of primary congenital hypothyroidism in Finland.

Incidence of primary congenital hypothyroidism and relationship between diagnostic categories and associated malformations.

The incidence of primary congenital hypothyroidism (CH) has grown progressively and literature data indicate an association between CH and congenital malformations. The purpose of this study is to establish the current incidence of CH in the Italian Region of Piedmont and verify the relationship between CH diagnostic categories and associated malformations. The biochemical and clinical data of 105 newborns with CH diagnosed in the period January 2014 to December 2019 were analyzed. The incidence of CH in the Italian Piedmont region in the 2014-2019 period increased to 1:1090. Thyroid dysgenesis was responsible for 47.6% (50/105) of all cases, with agenesis in 14.3% (15/105), while ectopia and hypoplasia in 23.8% (25/105) and 9.5% (10/105) of the cases, respectively; dyshormonogenesis defects were found in 52.4% (55/105) of cases. Congenital extra-thyroid anomalies were identified in 33/105 (31.4%) of newborns with CH and mainly involve the cardiac system (17/85, 16.1%), urogenital tract (7/85, 6.7%), gastrointestinal tract (5/105, 4.8%), and the musculoskeletal system (5/105, 4.8%). The highest rate of malformations was observed in patients with thyroid agenesis and dyshormonogenesis, respectively, in 53.5% and 36.4% of cases, while in the presence of thyroid ectopia and hypoplasia, the rate was 12% and 20%, respectively, (p = 0.03). In the Italian region of Piedmont, the incidence of primary CH has been increased over time, with a variation in the percentage of the different forms of CH. Congenital malformations, especially affecting the cardiovascular, urogenital, gastrointestinal, and musculoskeletal systems, seem to be mainly associated with thyroid agenesis or defects in hormonogenesis.

Ethnicity and incidence of congenital hypothyroidism in the capital of Macedonia.

Congenital hypothyroidism (CH) is a common and preventable cause of intellectual disability for which early diagnosis is difficult without newborn screening. Genetic and environmental factors, race, ethnicity, sex, and pregnancy outcomes were noted as risk factors. In the study we aimed to determine the incidence of CH among different ethnic groups in the capital of Macedoina - a multiethnic city. A 14-year retrospective cohort analysis was performed on 121,507 newborns in the capital of Macedonia, Skopje, screened for whole-blood thyroid-stimulating hormone (TSH), in dry blood spots collected 48-72 h after birth, during the period 2002-2015. A TSH value of 15 mIU/L was used as cutoff point until 2010 and 10 mIU/L thereafter. Primary CH was detected in 46 newborns (female to male ratio 1.3) with overall incidence of 3.8/10,000 (1/2641). The incidence of primary CH was significantly increased after lowering the TSH cutoff value (p=0.038), primarily due to detected neonates with transient CH for this period. Ethnic differences in the incidence of primary CH were detected. CH incidence among Roma neonates (6.7/10,000) was significantly higher (p<0.05) than the incidence detected in Macedonians (3.9/10,000) or Albanians (3.7/10,000). Increased incidence of CH in Roma newborns was detected as compared to other ethnicities in the capital of Macedonia. Further analysis of factors in direct interrelationship with the increased CH incidence in Roma newborns, as well as elucidation of impact of the CH incidence in this ethnicity on the overall incidence in Skopje, is warranted.

Changes in the incidence and etiology of congenital hypothyroidism detected during 30years of a screening program in central Serbia.

The overall incidence of CH in Central Serbia during study period nearly tripled, with a significant increase in almost all etiological categories, and was associated with lowering TSH cutoffs as well as other yet unidentified factors. Further studies are needed to identify other factors associated with increasing incidence of CH. Congenital hypothyroidism (CH) is the main cause of preventable mental retardation. Recent reports have indicated a progressive increase in the incidence of primary CH throughout the world, partially explained by lowering of the TSH cutoff values. During the study period associated with lowering of the TSH cutoffs, the overall incidence of CH in Serbia tripled, including transient CH, ectopy, and dyshormonogenesis, while prevalence of athyreosis remained stable during 30 years. Significant increase in the incidence of both permanent and transient CH was observed, associated with lowering of TSH cutoffs as well as other yet unidentified factors.

High Prevalence of Congenital Hypothyroidism in the Greek Cypriot Population: Results of the Neonatal Screening Program 1990- 2000

To evaluate the results of the screening program for congenital hypothyroidism (CH) in the Greek Cypriot population. During 1990-2000, 109,532 neonates were screened by TSH determination. Permanent CH was proven with biochemical findings after discontinuation of treatment for scintigraphy at the age of 3 years. Permanent CH was diagnosed in 61 infants, incidence 1/1800, with female/male ratio 2.05/1. The most common clinical findings were omphalocele (61%), large anterior fontanelles (49%) and edema of the eyelids (34%). The more delayed the bone maturation, the lower were initial T4 levels (p = 0.005). Bone maturation tended to be more advanced in thyroid hypoplasia and more delayed in thyroid agenesis (p = 0.049). Scintigraphy of the thyroid with TC99 revealed ectopia in 38%, thyroid agenesis in 36%, thyroid hypoplasia in 24% and dyshormonogenesis in 1.7%. Children with transient CH had significantly lower T4 and higher TSH values initially compared to those with permanent CH after birth; initial TSH level, however, failed to predict the nature of CH. Children with transient CH required less thyroxine dosage to maintain normal thyroid hormone levels and they had a normal thyroid gland on scintigraphy. The TSH level was normalized before the age of 2 months with a starting L-thyroxine dose of 10 microg/kg/daily. The incidence of primary CH in Greek Cypriots is 1/1800 live births. The most common etiology is thyroid dysgenesis. Initial T4 levels correlated with the degree of skeletal maturation and the etiology. Initial TSH level, although lower in children with transient CH, could not predict the nature of CH.

Regional and temporal fluctuations in the incidence of congenital hypothyroidism in Israel.

It is well known that the incidence of congenital hypothyroidism (CH) differs significantly among different parts of the world. Northern Israel has been shown to be an iodine deficient area with a relatively high incidence of CH. This study aimed to compare the incidence of CH between different regions of Israel and to examine the temporal fluctuations of this disease in each region. All 303 primary CH infants born in Israel during the 10-year period between April 1978 and March 1988 were classified by hospital of birth and place of residence. Using these data we calculated the incidence of CH in the different subdistricts and districts of Israel. We also calculated the annual incidence of CH in each district. The incidence of CH in each hospital was compared to the filter paper T4 levels of all newborns born in that hospital during 1993. The incidence of CH decreased gradually from northern to southern Israel. This trend was also observed for thyroid agenesis, but the incidence of ectopic thyroid was highest in central Israel. Dyshormonogenesis (DHG) was on average 3.5 fold more frequent in the Arab compared to the Jewish populations, but did not show any clear geographic pattern. A significantly increased CH incidence in north-central Israel in 1985 was opposed by a low incidence in the South. A clear correlation exists between the incidence of CH in each hospital and the mean newborns' T4 level in that hospital. The incidence of primary CH in general, and of thyroid agenesis and ectopic thyroid specifically, has a clear regional-temporal pattern. Thus, some of the factors causing CH in Israel may be local factors that show local annual fluctuations.

Congenital hypothyroidism: the Riyadh Military Hospital experience

We aimed to find out the incidence of primary congenital hypothyroidism (CH) among infants born within the Riyadh Al-Kharj Hospital Programme in addition to early detection and treatment of these infants. All babies born within the Riyadh Al-Kharj Hospital Programme were screened by cord blood TSH. Blood spot TSH were done in the majority of infants between 2 and 5 days after birth. All suspected cases were recalled for confirmatory tests. 123I thyroid scan and X-ray of the knee and maternal blood for thyroid antibodies were done for confirmed cases. A cut off TSH level of 30 mIU/l for cord blood and 25 mIU/l for spot blood were used. All samples were assayed by immunoassay methods. 44,778 (99.4% of the total births) infants were screened. Twenty-five cases were detected, four of which were excluded. The incidence of primary congenital hypothyroidism was 1/2096. Five cases were missed on the initial screen. Eight out of 17 children who had 123I thyroid scan were found to have dyshormonogenesis. Associated malformation and diseases were diagnosed in 42.85%. Two had chromosomal anomalies; ring chromosome 9 has not been previously reported in association with congenital hypothyroidism. The incidence of congenital hypothyroidism, dyshormonogenesis and the associated malformations and diseases are higher than those reported in the literature. Cord blood as a screening method is associated with a significant number of missed cases.

Distribution of TSH levels on dried blood spots in 188.872 Greek newborns: incidence of primary congenital hypothyroidism

Distribution of TSH levels on dried blood spots in 188.872 Greek newborns: incidence of primary congenital hypothyroidism

Distribution of TSH levels in dried blood spot among 137,207 Greek newborns: incidence of Primary Congenital Hypothyroidism and Transient Hyperthyrotropinemia

In September 1979 screening for Congenital Hypothyroidism (C.H.) was started in Greece. As the screening method Thyroid-Stimulating Hormone (TSH) determination in dried blood spots collected on the 5th day of life was chosen. To date 137,207 newborns (65% of all live births in Greece) have been screened. The distribution of TSH levels in a single estimation was as follows: < 12.5μIU/ml 87.7%, 12.5-30μIU/ml 11.4% and > 30μIU/ml 0.9%.Values > 30μIU/ml were confirmed by a second estimation from the initial card in 171 cases, which were recalled for a new blood specimen (recall rate 0.12%). Among them 97 had TSH values between 30 and 50μIU/ml and TSH estimation from a blood spot on a new card 1-3 months later showed TSH values < 12.5μIU/ml. In 41 cases with TSH values 50-80μIU/ml, serum TSH and T4 revealed 4 cases of C.H. (9.7%), while 37 cases had serum TSH and T4 values within normal limits and were considered as Transient Hyperthyrotropinemias (T.H.). Finally among 33 cases with initial TSH values > 80μIU/ml, in 29 (88%) the diagnosis of C.H. was confirmed on biochemical and clinical grounds, while 4 were considered as T.H. The overall incidence of primary C.H. in our population was 1:4,157.