Risk Factors For Congenital Hypothyroidism Research Articles

Perinatal risk factors for congenital hypothyroidism in very preterm infants: a multicenter prospective study

Objective: To investigate the incidence and perinatal risk factors of congenital hypothyroidism (CH) in very preterm infants. Methods: This prospective, multicenter observational cohort study was conducted at 33 neonatal intensive care units based on the data from Sina-northern Neonatal Network (SNN). Perinatal information and thyroid function of 3 179 very preterm infants with gestational age <32 weeks who were born from January 2019 to June 2021 was collected. According to the occurrence of CH during hospitalization, all the infants were assigned into CH group and non-CH group. Chi square test, Fisher exact probability method, rank sum test and multivariate Logistic regression model were tested to detect the perinatal risk factors for CH. Results: A total of 3 179 very preterm infants were enrolled with 56.4% (1 793/3 179) male. The incidence of CH was 6.9% (220/3 179), in which the incidence for extremely low birth weight infant (ELBWI) and extremely preterm infants (EPI) of gestational age <28 weeks were 13.5% (64/475) and 13.9% (66/475), respectively. On Logistic regression analysis, maternal hypertensive disorders of pregnancy (OR=1.59, 95%CI 1.14-2.23, P=0.007) and multiple birth (OR=1.60, 95%CI 1.18-2.17, P=0.003) were both significant perinatal risk factors of CH. In addition, gestational age (OR=0.81, 95%CI 0.71-0.93, P=0.002), birth weight (OR=0.99, 95%CI: 0.98-0.99, P<0.001) and 1 min Apgar score (OR=0.92, 95%CI 0.86-0.98, P=0.008) were protective factors. Conclusions: The incidence of CH is high in very preterm infants which increased with the decreased birth weight and gestational age. For very premature infants with perinatal high risk factors such as hypertensive disorders of pregnancy, attention should be paid to assess thyroid function status dynamically.

Investigation of Risk Factors of Congenital Hypothyroidism in Children in Southwestern Iran.

Due to the fact that congenital hypothyroidism is one of the preventable causes of mental retardation, so this study was conducted to determine the risk factors in children with congenital hypothyroidism. In this descriptive-analytical cross-sectional study, the study population included all children with congenital hypothyroidism referred to outpatient clinics of teaching hospitals whose congenital hypothyroidism was diagnosed by a physician specializing in this field from the first months after birth. The data collection tool is a researcher-made checklist that includes individual and clinical variables (age, sex, height, weight, several children in the family, etc.). In order to analyze the data, SPSS19 software and descriptive statistics such as mean, standard deviation and frequency percentage were used to describe the demographic information. The significance level used in statistical tests was considered equal to 0.05. The results of this study showed that out of 350 affected children, 163 (46.6) were girls and 187 (53.4) were boys. Also, the majority of children are over 6 years old (35.14%). Most children live in the city (88.57%). Also 55.71% of mothers of affected children had a normal delivery. 57.42% of the parents of children have a family relationship. According to the results of this study, many risk factors for congenital hypothyroidism are identified. Therefore, based on these findings, Health planners should consider the necessary strategies to prevent and control this congenital disease in a timely manner.

Perinatal risk factors for congenital hypothyroidism: A retrospective cohort study performed at a tertiary hospital in China.

Congenital hypothyroidism (CH) is one of the most common neonatal endocrine diseases. This retrospective cohort study aimed to identify the potential perinatal risk factors for CH and to differentiate between transient and permanent CH (TCH and PCH, respectively) as well as determine their prevalence in a southeastern Chinese population.This study was based on an 18-year surveillance of a neonatal CH screening program in a large tertiary hospital. A retrospective review of the maternal and neonatal perinatal exposures was conducted.Of the 205,834 newborns screened between 2000 and 2018, 189 were diagnosed with CH (1/1089). Among the 131 CH patients who again underwent thyroid function testing (TFT) after discontinuation of levothyroxine at the age of 3 years, 61 (46.6%) were diagnosed with PCH and 70 (53.4%) were diagnosed with TCH. In the maternal characteristics model, women aged 35 years or older and those who had thyroid disease and/or diabetes mellitus during pregnancy had increased risk of having an offspring with CH (P = .001, .000, and .001, respectively). Significant associations were found with regard to parity and the risk of CH in the offspring (P = .000). In the neonatal characteristics model, infants with female sex, preterm birth, post-term birth, low birth weight, other birth defects, and those born as part of multiple births (P = .011, .034, .001, .000, .000, and .003, respectively) had increased risk of CH. The rate of newborns with other birth defects was higher in the PCH group than that in the TCH group (P = .008), whereas the rate of maternal thyroid disease, newborns with low birth weight, and newborns with preterm birth was higher in the TCH group than that in the PCH group (P = .041, .020, and .013, respectively). The levothyroxine dose (μg/kg/day) at 1 year, 2 years, and 3 years old was significantly lower in the TCH group than that in the PCH group (P = .000, .000, and .000, respectively).Perinatal factors should be considered during the diagnosis and treatment of CH.

Epidemiologic Characteristics and Risk Factors for Congenital Hypothyroidism from 2009 to 2018 in Xiamen, China

Objective: Early diagnosis and treatment of children with congenital hypothyroidism (CH) through newborn screening can effectively prevent delayed development. This study was designed to investigate the pathogenesis and factors that influence CH in urban areas of China between 2009 and 2018. Methods: A retrospective analysis of newborn screening data and diagnosis and treatment information for CH diagnosed in the information database of the neonatal disease screening center in one of China's five special economic zones from 2009 to 2018. Results: Of the 947,258 newborns screened between 2009 and 2018, 829 (406 girls) were diagnosed with CH at birth (1 diagnosis/1,136 births). Among the 608 cases of CH diagnosed at birth and re-evaluated at the age of 3 years, 487 were permanent congenital hypothyroidism (PCH, 1/1,429), and 121 were transient congenital hypothyroidism (TCH, 1/5,882). A total of 83.2% of infants with PCH (405/487) underwent thyroid imaging in the neonatal period, of which thyroid dysgenesis accounted for 28.64% (116/405) and functional defects accounted for 71.36% (289/405). The incidence of CH changed significantly in infants with initial serum thyroid-stimulating hormone concentrations of 41 to 100 mIU/L and ≥100 mIU/L, whereas the incidence of mild CH showed a slight increase. The incidence of CH was significantly higher in postterm infants (1/63) and low-birth-weight infants (1/370). Conclusion: In the past decade, the incidence of CH has increased, mainly due to the increase in the incidence of PCH and TCH. The incidence of mild CH has increased slightly. Postterm birth and low birth weight are important factors affecting the incidence of CH. Abbreviations: CH = congenital hypothyroidism; FT4 = free thyroxine; L-T4 = levothyroxine sodium; PCH = permanent congenital hypothyroidism; TCH = transient congenital hypothyroidism; TSH = thyroid-stimulating hormone; TT4 = total thyroxine.

Congenital Hypothyroidism: 8-Year Experience Using 2 Newborn Screens in Alabama

Background/Aims: Newborn screening protocols for congenital hypothyroidism (CH) vary as to whether a TSH or T4 algorithm or some combination is performed. We aimed to determine the 3-year clinical outcome of infants diagnosed with CH and screen-positive for CH using a 2-screen protocol that measures both T4 and TSH on all specimens. Methods: Retrospective analysis of patients with CH who were detected by first (NBS1) or second (NBS2) newborn screen in Alabama (2009–2016) and followed at our university-based practice. Clinical follow-up established the final diagnoses in 146 patients, including a subset of 72 patients with eutopic glands. Results: 168 patients were studied: 139 (83%) were detected by NBS1 and 29 (17%) by NBS2. Screening T4 concentrations were 45% reduced in NBS2 compared to NBS1 (p= 0.0002). Thyroid dysgenesis was present in 55% of NBS1 patients while all in NBS2 were eutopic. Follow-up of 146 patients confirmed permanent CH in 92 patients in NBS1 (75%) and 5 in NBS2 (20%). Hispanic infants were only detected by NBS1, and 93% had permanent CH. Transient CH was associated with congenital heart disease. In patients with eutopic, permanent CH, dyshormonogenesis was confirmed in 23% of NBS1 patients and 40% of NBS2. One case of central CH was detected by each screen. Conclusions: This 8-year, retrospective study buttresses the importance of a 2-screen approach for CH by identifying 5 infants with clinically significant permanent thyroid dysfunction including dyshormonogenesis and central hypothyroidism. It is the first 2-screen study to incorporate thyroid ultrasound. Disconcertingly, 4 of 5 second-screen infants with permanent CH had no risk factors for CH, and these infants would otherwise not have been detected.

Investigation of the Risk Factors for Congenital Hypothyroidism in Iran: A Population-Based Case-Control Study

Background Congenital hypothyroidism (CH) is one of the most common causes of mental disability, which can be prevented in the case of early diagnosis and treatment. We aimed to study the some relevant risk factors for CH in neonates born in Khorasan Razavi Province, Iran. Materials and Methods: This was a population-based case-control study conducted on 97,380 neonates.The study population consisted of neonates born from April, 2016 to March, 2018 and undergone a screening program for CH.Overall, 530 neonates diagnosed with CH by a specialist were assigned to a case group and the remaining were considered as controls. Information was extracted from the Sina Electronic Health Record System (SinaEHR®, Iran). Bivariate and multivariate logistic regressions were carried out to determine the associations between independent variables and CH. Results: Of the 97,380 neonates, the case and control groups included 530 (248 females) and 96,860 (47,061 males) newborns, respectively. In multivariate analysis, the use of neonate formula (adjusted odds ratio [AOR]=0.63; 95% confidence interval [CI]: 0.43-0.93, P=0.02), medication during pregnancy (AOR=1.29; 95% CI: 0.86-1.94, P=0.23), maternal hypertension (AOR=3.25; 95% CI: 1.15-9.19, P=0.03), maternal depression (AOR=2.19; 95% CI: 1.16-4.14, P=0.02), maternal diabetes (AOR=0.65; 95% CI: 0.51-0.83, P=0.001), consanguineous marriage (AOR=1.34; 95% CI:1.12-1.60, P=0.002), place of residence, and birth season after adjusting for confounding variable remained in the final model. Conclusion: The study findings showed that birth season, place of residence, maternal hypertension and depression, and consanguineous marriage can be the main risk factors for CH. However, further studies are needed to analyze the findings of the present study to be more confident about the causality of these relationships.

Epidemiologic characteristics and risk factors for congenital hypothyroidism from 1989 to 2014 in Beijing

To investigate the epidemiologic characteristics and risk factors for congenital hypothyroidism (CH) in Beijing between the years 1989 and 2014. Information on neonatal screening, and diagnoses and treatment of CH from 1989 to 2014 were obtained from the database of the Beijing Neonatal Screening Center. The screening parameter was thyroid-stimulating hormone (thyrotropin; TSH), which was measured by radioimmunoassay (RIA) from 1989 to 1995, enzyme-linked immunosorbent assay (ELISA) from 1996 to 2003, and time-resolved fluorescence immunoassay (DELFIA(®)) from 2004 to 2014. The cutoff value of each screening method was set as the international standard for the corresponding years (20 mIU/L from 1989 to 1995 and 10 mIU/L from 1996 to 2014). CH was diagnosed using "The Technical Specification of Diagnosis and Treatment of Phenylketonuria and Congenital Hypothyroidism" , published in 2010 by the Ministry of Health of the People's Republic of China. Data on live birth infants were obtained from Beijing obstetric quality reports. The incidence of CH using different screening methods was compared, and trends in annual incidence were analyzed. To exclude the influence of different screening methods, data from the years 2004 to 2014 were used to identify the risk factors for CH. Between 1989 and 2014, the incidence of CH in Beijing was 36.7 per 100 000 individuals, with permanent CH (PCH) and transient CH (TCH) having incidences of 16.4 per 100 000 and 15.9 per 100 000, respectively. The annual incidence of CH increased from 11.2 per 100 000 in 1989 to 51.0 per 100 000 in 2014 (χ(2)=119.02, P<0.001), with PCH increasing from 5.6 to 16.0 per 100 000 (χ(2)=34.38, P<0.001) and TCH increasing from 5.6 to 13.0 per 100 000 (χ(2)=26.93, P<0.001). Among the PCH cases, 70.44% (255/362) were thyroid dysgenesis or ectopic glands, while the other 29.56% (107/362) were dyshormonogenesis. Between 2004 and 2014, the incidence of CH in females (51.7/100 000) was higher than in males (37.0/100 000), and it was higher in post-term (334.5/100 000) and preterm births (77.8/100 000) than that in term births (41.4/100 000). It was also higher in the low birth weight (87.7/100 000) than the normal (42.4/100 000) and high birth weight (42.6/100 000) populations. Between 1989 and 2014, there was a tendency towards an increase in the overall incidence of CH, and the incidence of both PCH and TCH in Beijing. Female sex, preterm birth, older gestational age, low birth weight, and preterm birth were risk factors affecting the incidence of CH in Beijing.

Risk factors for congenital hypothyroidism in Egypt: results of a population case-control study (2003–2010)

BACKGROUND AND OBJECTIVESAlthough the prevention of the neuropsychological consequences of congenital hypothyroidism (CH) through the use of replacement therapy represents an important public health success, knowledge about the modifiable risk factors could reduce the number of infants affected by this disease. This study was carried out to identify risk factors for CH at Fayoum Governorate, Egypt.DESIGN AND SETTINGSThis was a population-based case-control study, which started in 2003 and was carried out for 8 years through Fayoum center of the Egyptian Ministry of Health and Population screening program for CH.METHODSThis study was a population-based case-control study carried out by using national project for CH. One control was enrolled for each new CH infant; 320 cases and 320 controls were enrolled in 8 years. Maternal and neonatal influences were investigated.RESULTSA statistically significant association of CH was observed with birth defects, female gender, gestational age >40 weeks, and gestational diabetes. An increased risk for CH was detected in twins by a multivariate analysis.CONCLUSIONOur results suggest a multifactorial origin of CH in which genetic (high frequency of additional malformations) and environmental factors (especially maternal diabetes) play a role in the development of the disease.

Prevalence of Congenital Hypothyroidism—Current Trends and Future Directions: Workshop Summary

In response to published newborn-screening data that have shown an increase in the incidence (birth prevalence) rate of primary congenital hypothyroidism (CH) in the United States, a workshop was held in Atlanta, Georgia, on February 27 and 28, 2008, to examine this issue. Topics of the meeting included pathophysiology, medical management, and follow-up of CH; transient hypothyroidism (etiology, clinical implications, management, and changes in prevalence); risk factors for CH; laboratory approaches to newborn screening for CH; state-specific evaluations of trends in incidence rates of CH; and concluding discussions on future directions to resolve outstanding issues. Through presentations and discussion, gaps in knowledge were identified, such as the lack of consistent definitions for CH and transient hypothyroidism and the effects of preventable risk factors on incidence rates of CH. One outcome of the meeting was a series of accompanying articles that examined (1) trends in the incidence rates of CH in individual states and nationally, (2) effects of newborn-screening practices on CH-incidence rates, (3) the contribution of transient hypothyroidism to CH-incidence rates, and (4) future research directions. In this summary, we briefly touch on the topics of these articles and examine highlights of other presentations from the workshop that illuminated the secular trends in reported CH-incidence rates in the United States.

Risk factors for congenital hypothyroidism: results of a population case-control study (1997–2003)

To identify risk factors for permanent and transient congenital hypothyroidism (CH). A population-based case-control study was carried out by using the network created in Italy for the National Register of Infants with CH. Four controls were enrolled for each new CH infant; 173 cases and 690 controls were enrolled in 4 years. In order to distinguish among risk factors for permanent and transient CH, diagnosis was re-evaluated 3 years after enrollment when there was a suspicion of transient CH being present. Familial, maternal, neonatal and environmental influences were investigated. An increased risk for permanent CH was detected in twins by a multivariate analysis (odds ratio (OR) = 12.2, 95% confidence interval (CI): 2.4-62.3). A statistically significant association with additional birth defects, female gender and gestational age >40 weeks was also confirmed. Although not significant, an increased risk of CH was observed among infants with a family history of thyroid diseases among parents (OR = 1.9, 95% CI: 0.7-5.2). Maternal diabetes was also found to be slightly associated with permanent CH (OR = 15.7, 95% CI: 0.9-523) in infants who were large for gestational age. With regard to transient CH, intrauterine growth retardation and preterm delivery were independent risk factors for this form of CH. This study showed that many risk factors contribute to the aetiology of CH. In particular, our results suggested a multifactorial origin of CH in which genetic and environmental factors play a role in the development of the disease.

Risk factors for congenital hypothyroidism: An investigation of infant's birth weight, ethnicity, and gender in California, 1990–1998

Background Approximately 85% of primary congenital hypothyroidism (CH) is sporadic and due to malformations of the thyroid gland. Past studies have reported an increased birth weight among infants with CH. We have attempted to replicate and expand these observations, examining the association between different birth weight categories and CH stratified by infant's sex. We have also examined the prevalence of CH by mother's age and infant's ethnicity, gender, and year of birth. Methods A cross-sectional study was conducted on 5,049,185 infants screened by the statewide California Newborn Screening Program between 1990 and 1998, an estimated 98.6% of all newborns in the state. Dried blood spots from a heel stick were assayed for thyroxine (T4), and presumptive positives had follow-up assays of thyroid-stimulating hormone (TSH) to determine definite positives. Results A total of 1,806 cases of CH were identified. The following findings are unlikely to be due to chance. Compared with infants with birth weights of 3,000–3,499 g, infants weighing <2,000 g and those weighing ≥4,500 g had a twofold or greater increase in the prevalence of CH. This was not explained as a result of confounding by the infant's ethnicity or gender. Compared with whites, elevated prevalence rates were found in most ethnic groups, which include the following: Hispanics, Chinese, Vietnamese, Asian Indians, Filipinos, Middle Easterners, and Hawaiians. As reported previously, black infants had about one-third the prevalence rate of whites. We also observed the frequently described female preponderance of CH. The female excess was maintained at all birth weights, however it varied by infant's ethnicity. Trends in the prevalence of CH were not associated with mother's age or with the time interval between 1990 and 1998. Conclusions We observed an increased risk of CH in both low-birth-weight (<2,000-g) and macrosomic (≥4,500-g) infants. This U-shaped association has not been described in past studies. We have also expanded the previously described ethnic differences in CH risk to include ethnic groups not previously studied. The unique pattern of CH occurrence suggests that further studies to define modifiable risk factors may be useful. Teratology 62:36–41, 2000. © 2000 Wiley-Liss, Inc.