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

Quality of life and socioeconomic and educational status in patients with congenital hypothyroidism

BACKGROUND

The aim of this study was to investigate the influence of primary congenital hypothyroidism (CH) on quality of life, level of education and socioeconomic status (SES).

METHODS

Two independent study cohorts, a national and a regional, were collected from Finnish national registers and patient records. Data on social security benefits, SES, marital status, and education were collected from Statistics Finland. Health-related quality of life (HRQoL) was studied in the regional patient cohort with the standardized 15D and 16D instruments.

RESULTS

There were no statistically significant differences in education level, marital status, or SES between CH patients (n = 40) and their matched controls at the age of 25 years. The mean 15D score was both statistically significantly and clinically importantly lower in CH patients (n = 29) than controls (0.904 vs. 0.953, p = 0.008). CH patients reported significantly lower scores across various dimensions of physical and mental HRQoL, including breathing, sleeping, speech, excretion, mental function, distress, and vitality. The mean 16D score was lower in CH patients compared to controls (0.917, vs. 0.947), but without statistical significance.

CONCLUSION

SES of CH patients did not differ from matched controls. Thus, most CH patients integrate well into society, but their HRQoL is impaired.

IMPACT

Most patients with primary congenital hypothyroidism integrate well into society. In the current study, their socioeconomic and marital status did not differ from matched controls at the age of 25 years. However, health-related quality of life measured using 15D instrument was impaired. Every fourth patient reported that congenital hypothyroidism influenced everyday life.

History of Neonatal Screening of Congenital Hypothyroidism in Portugal

Congenital hypothyroidism (CH) leads to growth and development delays and is preventable with early treatment. Neonatal screening for CH was initiated in Portugal in 1981. This study examines the history of CH screening in the country. Data were obtained from annual reports and from the national database of neonatal screening laboratory. The CH screening strategy primarily relies on the thyroid-stimulating hormone (TSH), followed by total thyroxine measurement as the second tier for confirmation. The TSH cutoff started at 90 mIU/L, decreasing to the actual 10 mIU/L. The coverage of the screening program has increased rapidly; although voluntary, it reached about 90% in 6 years and became universal in 10 years. Guideline and cutoff updates led to the identification of over 200 additional cases, resulting in specific retesting protocols for preterm and very-low-birth-weight babies. The actual decision tree considers CH when TSH levels are above 40 mIU/L. Data from the CH screening also provide an indication of the iodine status of the population, which is presently indicative of iodine insufficiency. The Portuguese neonatal screening for CH is a history of success. It has rapidly and continuously adapted to changes in knowledge and has become a universal voluntary practice within a few years.

Comorbidity in Congenital Hypothyroidism-A Nationwide, Population-based Cohort Study

CONTEXT

Patients with congenital hypothyroidism (CH) are affected more often than the general population by other chronic diseases and neurological difficulties.

OBJECTIVE

The aim of this nationwide population-based register study was to investigate the incidence of congenital malformations, comorbidities, and the use of prescribed drugs in patients with primary CH.

METHODS

The study cohort and matched controls were identified from national population-based registers in Finland. All diagnoses from birth until the end of 2018 were collected from the Care Register, and subject-specific prescription drug purchases were identified from The Prescription Register from birth until the end of 2017.

RESULTS

Diagnoses of neonatal and chronic diseases were collected for 438 full-term patients and 835 controls (median follow-up time 11.6 years; range, 0-23 years). Newborns with CH were more often found to have neonatal jaundice (11.2% and 2.0%; P < .001), hypoglycemia (8.9% and 2.8%; P < .001), metabolic acidemia (3.2% and 1.1%; P = .007), and respiratory distress (3.9% and 1.3%; P < .003) as compared to their matched controls.Congenital malformations were diagnosed in 66 of 438 (15.1%) CH patients and in 62 of 835 (7.4%) controls (P < .001). The most commonly affected extrathyroidal systems were the circulatory and musculoskeletal systems. The cumulative incidence of hearing loss and specific developmental disorders was higher among CH patients than controls. The use of antidepressant and antipsychotic drugs was similar in CH patients and their controls.

CONCLUSION

CH patients have more neonatal morbidity and congenital malformations than their matched controls. The cumulative incidence of neurological disorders is higher in CH patients. However, our results do not support the existence of severe psychiatric comorbidity.

Neonatal Endocrine Diseases

Endocrine diseases are rare and can present very subtly in the neonatal period. Most are diagnosed using newborn screening in the United States; however, some infants may present with false negatives or more subtle findings. Endocrine etiologies should be considered during the management of critically ill infants. This article will give an overview of endocrine emergencies encountered in the neonatal period, including disorders of glucose metabolism, thyroid disorders, adrenal disorders, and pituitary disorders.

Per- and polyfluoroalkyl substances (PFAS) and thyroid hormone measurements in dried blood spots and neonatal characteristics: a pilot study

BACKGROUND

Pediatric thyroid diseases have been increasing in recent years. Environmental risk factors such as exposures to chemical contaminants may play a role but are largely unexplored. Archived neonatal dried blood spots (DBS) offer an innovative approach to investigate environmental exposures and effects.

OBJECTIVE

In this pilot study, we applied a new method for quantifying per- and polyfluoroalkyl substances (PFAS) to 18 archived DBS from babies born in California from 1985-2018 and acquired thyroid hormone measurements from newborn screening tests. Leveraging these novel data, we evaluated (1) changes in the concentrations of eight PFAS over time and (2) the relationship between PFAS concentrations, thyroid hormone concentrations, and neonatal characteristics to inform future research.

METHODS

PFAS concentrations in DBS were measured using ultra-high-performance liquid chromatography-mass spectrometry. Summary statistics and non-parametric Wilcoxon rank-sum and Kruskal-Wallis tests were used to evaluate temporal changes in PFAS concentrations and relationships between PFAS concentrations, thyroid hormone concentrations, and neonatal characteristics.

RESULTS

The concentration and detection frequencies of several PFAS (PFOA, PFOS, and PFOSA) declined over the assessment period. We observed that the timing of specimen collection in hours after birth was related to thyroid hormone but not PFAS concentrations, and that thyroid hormones were related to some PFAS concentrations (PFOA and PFOS).

IMPACT STATEMENT

This pilot study examines the relationship between concentrations of eight per- and polyfluoroalkyl substances (PFAS), thyroid hormone levels, and neonatal characteristics in newborn dried blood spots (DBS) collected over a period of 33 years. To our knowledge, 6 of the 22 PFAS we attempted to measure have not been quantified previously in neonatal DBS, and this is the first study to examine both PFAS and thyroid hormone concentrations using DBS. This research demonstrates the feasibility of using newborn DBS for quantifying PFAS exposures in population-based studies, highlights methodological considerations in the use of thyroid hormone data for future studies using newborn DBS, and indicates potential relationships between PFAS concentrations and thyroid hormones for follow-up in future research.

Incidence of primary congenital hypothyroidism over 24 years in Finland

BACKGROUND

A 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.

METHODS

Two 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.

RESULTS

Between 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.

CONCLUSIONS

In Finland, the incidence of CH has not changed during the 24-year study period.

IMPACT

As 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.

Mother's iodine exposure and infants' hypothyroidism: the Japan Environment and Children's Study (JECS)

In this study, we aimed to determine the association of neonatal/post-neonatal hypothyroidism with mother's iodine exposure, especially povidone iodine disinfection, and hysterosalpingography. Participants were mother-child pairs in a Japanese birth cohort (n = 100,286). Risk factors of hypothyroidism were supplement intake, seaweed intake, other daily iodine intake, povidone iodine disinfection at delivery, and maternal history of hysterosalpingography, thyroid disease (Graves' disease and Hashimoto's thyroiditis), and medication (thiamazole and levothyroxine). Congenital hypothyroidism (CH) at age 1 year was assessed using a questionnaire. Transient hypothyroidism was defined as elevated thyroid stimulating hormone level at birth and absence of CH at age 1 year. The incidence of CH at age 1 year per 100 children was 1.1 for those born at 22-30 weeks' gestation, 0.17 following povidone iodine disinfection, and 0.07, 0.95, 0.81, 1.17, and 1.15 with a maternal history of hysterosalpingography, Graves' disease, Hashimoto's thyroiditis, thiamazole use, and levothyroxine use, respectively. Odds ratios (95% confidence intervals) of CH at age 1 year for povidone iodine disinfection, hysterosalpingography history, maternal Graves' disease, and maternal Hashimoto's thyroiditis were 1.13 (0.71-1.79), 0.47 (0.07-3.36), 7.06 (3.70-13.5), and 5.93 (2.90-12.1), respectively. For transient hypothyroidism for povidone iodine disinfection and hysterosalpingography history, these values were 1.99 (1.51-2.62) and 0.63 (0.20-1.96), respectively. Maternal thyroid disease greatly increased neonatal/post-neonatal hypothyroidism risk. Povidone iodine disinfection may increase transient hypothyroidism risk but not the risk at 1 year of age. Hysterosalpingography does not increase hypothyroidism risk from birth to age 1 year.

A suggested screening method for hypothyroidism in very preterm and/or very low birth weight neonates

Objective:

To assess thyroid function in very preterm or very low birth weight (VLBW) neonates by measuring combination levels of thyroid-stimulating hormone TSH and free T4 (FT4)

Methods:

Inclusion criteria were defined as all very preterm (gestational age <32 weeks) or VLBW (birth weight ≤1500g) neonates with initial Thyroid Function Test (TFT) who were admitted to the Neonatal Intense Care Unit (NICU) of Taleghani Hospital, Tabriz, Iran, from March 2015 to March 2016. Exclusion criteria were the absence of initial TFT with any major congenital anomaly. The primary value of TSH was evaluated at 3–5 days, and mean levels of TSH with FT4 were measured at 2, 4, and 8-weeks.

Results:

Ninety-five neonates with a mean gestational age of 29.5 weeks were included, and the mean levels of thyrotropin and FT4 at postnatal week two were 4.4mIU/L and 1.4ng/dL, respectively. Two of the patients had serum TSH concentration >25mIU/L that was considered as permanent primary hypothyroidism. Among nine hypothyroxinemia cases, two had elevated TSH levels (10.8±0.4mIU/L at the end of 8 weeks) and normal FT4 concentration, and were considered transient hypothyroidism. Seven cases had normal TSH levels (1.6±1.0mIU/L at 2 weeks, 3.5±2.8mIU/L at 8 weeks) and low FT4 concentrations.

Conclusions:

Combined venous TSH and FT4 concentration at the end of the first postnatal month can be an efficient approach for detecting neonatal hypothyroidism.

ADHESION TO TREATMENT BY CHILDREN WITH CONGENITAL HYPOTHYROIDISM: KNOWLEDGE OF CAREGIVERS IN BAHIA STATE, BRAZIL

OBJECTIVE

To investigate knowledge of caregivers of children with congenital hypothyroidism (CH), followed in a public reference service, as well as their associations with treatment adherence.

METHODS

Exploratory, descriptive, cross-sectional study with convenience sample. Medical records of 158 patients diagnosed with congenital hypothyroidism were analyzed, and data were evaluated by applying a previously prepared questionnaire to caregivers from 2014 to 2016. Statistical analysis used the chi-square and the Spearman's correlation tests, being significant p-value ≤0.05.

RESULTS

Females were predominant among caregivers (94.3%), with a mean age of 31 years, from inland cities (77.8%). There was a predominance of socioeconomic class C (59.5%) and incomplete primary education (35.7%). More than half of patients (53.2%) with CH had an adequate hormonal control. Approximately one third of caregivers had poor knowledge (37.3%) or was unaware (24.1%) about the meaning of congenital hypothyroidism. The low knowledge level of the disease was observed to be related to caregivers' educational level (p=0.004).

CONCLUSIONS

Lack of education of caregivers was a barrier to be faced when monitoring children with CH. This reality requires greater attention from health professionals to ensure that they use clear language when giving instructions to caregivers, and that caregivers have adequately understood the proposed recommendations.

The Laboratory Features of Congenital Hypothyroidism and Approach to Therapy

Congenital hypothyroidism (CH) is one of the most common preventable causes of intellectual disability. Thyroid hormone is required for normal brain development, but neonates with CH typically appear healthy at birth, which leads to delays in diagnosis and treatment. In developed countries, newborn screening programs have led to earlier diagnosis and treatment of CH, resulting in improved neurodevelopmental outcomes. Neonates with an abnormal newborn screen require prompt confirmatory serum thyroid function tests and treatment with thyroid hormone. Further evaluation for the etiology of CH should not delay treatment decisions.

Newborn Screening for Congenital Hypothyroidism: the Benefit of Using Differential TSH Cutoffs in a 2-Screen Program

CONTEXT

Analysis of a 2-screen program for congenital hypothyroidism (CH) was performed using differential dried-blood spot thyrotropin (bTSH) cutoffs of 10 mU/L at first screening (all infants) and 5 mU/L at second screening (selected infants).

OBJECTIVES

This work aimed to characterize CH infants identified by the second screening and compare infants with bTSH of 5.0 to 9.9 and 10 mU/L or greater on second screening.

DESIGN AND PATIENTS

Maternal and neonatal clinical features were retrospectively analyzed for 119 CH babies detected on the second screen in the Lombardy region of Italy, 2007 to 2014.

RESULTS

Fifty-two (43.7%) of the 119 CH neonates showed bTSH values ranging from 5.0 to 9.9 mU/L at the second screening (low bTSH group) and 67 (56.3%) bTSH of 10.0 mU/L or greater (high bTSH group). The frequency of thyroid dysgenesis and eutopic gland was similar in both groups, as was the frequency of permanent and transient CH. Moreover, a high frequency of extrathyroidal malformations was found in both groups. The percentage of preterm infants (57.7% vs 23.9%, P < .001) and infants admitted to the neonatal intensive care unit (50.0% vs 17.9%, P < .001) was significantly higher in the low vs the high bTSH group. In addition, maternal treatment with glucocorticoids in pregnancy was significantly more frequent in the low bTSH group than in the high bTSH group (11.5% vs 1.5%, P = .042), as well as maternal hypothyroidism and/or goiter (26.9% vs 10.4%, P = .036).

CONCLUSIONS

This study has demonstrated that a lower TSH cutoff at the second screening can detect additional cases of CH and that a second bTSH cutoff of 5.0 mU/L is appropriate for identifying preterm newborns and babies with associated risk factors.

Congenital Hypothyroidism and its Related Factors in an Iranian Population: A Retrospective Study in Semnan (2011-2016)

Background:

Congenital hypothyroidism (CH) is an important and preventable cause of intellectual disability. This study determined the incidence of CH and its related factors in Semnan city in Iran.

Methods:

All neonates born in Semnan from 2011 to 2016 who participated in a screening program for CH were evaluated to estimate the incidence of CH. In a nested case-control study, all diagnosed CH cases were compared with a control group of healthy newborns. Statistical analysis used conditional logistic regression model with STATA-14.

Results:

106 out of 17,507 neonates born in Semnan during 2011–2016 were diagnosed with CH (6.05 cases per 1,000 live births). Maternal parity (odds ratio [OR] =1.78, P = 0.044), birth weight (OR = 0.29, P = 0.001), parental history of thyroid disease (OR = 3.43, P = 0.001), father's education (OR = 0.71, P = 0.003), father's occupation (nonworker) (OR = 2.97, P = 0.001), and the presence of other anomalies (OR = 4.14, P = 0.037) were related to the incidence of CH.

Conclusions:

The cumulative incidence of CH in Semnan was higher than in both the global and national statistics. Aside from well-known medical determinants, some important social factors such as father's occupation and education have a significant and independent relationship with occurrence of CH; rational attention should be given to them in health care programs to increase the effectiveness of preventative measures for CH.

Newborn Iodine Status Is Not Related to Congenital Hypothyroidism

BACKGROUND

Severe iodine deficiency or excess during pregnancy can cause congenital hypothyroidism (CH). Iodine deficiency is common in pregnant women in the United States.

OBJECTIVES

We conducted a nested case-control study in a cohort of ∼2.5 million births in California to determine whether iodine status is related to CH in a US population.

METHODS

Dried blood spots from 907 newborns with CH identified by newborn screening and 909 unaffected controls matched by month of birth were obtained from the California Newborn Screening Program to measure whole-blood iodine concentration. Iodine status was compared between cases and controls, and logistic regression was used to assess the association between CH status and blood iodine concentrations. Iodine status was also compared between cases and controls among infants treated in a neonatal intensive care unit (NICU) because CH has been reported in infants exposed to high levels of iodine in the NICU.

RESULTS

Blood iodine concentrations did not differ significantly between cases (median: 20.0 ng/mL; IQR: 12.1-29.8 ng/mL) and controls (median: 20.3 ng/mL; IQR: 12.5-30.9 ng/mL; P = 0.59). Neither extremely high nor extremely low blood iodine concentrations (1st, 5th, 95th, and 99th percentiles of the distribution) were more common in cases. Among infants treated in NICUs, however, cases had significantly (P = 0.01) higher iodine (median: 22.7 ng/mL; IQR: 16.4-32.1 ng/mL) compared with controls (median: 17.3 ng/mL; IQR: 8.3-26.6 ng/mL).

CONCLUSIONS

CH cases did not have significantly higher or lower iodine in this population, which is reassuring given that maternal iodine deficiency is common in the United States. Among newborns in the NICU, CH cases had higher blood iodine concentrations compared with controls, suggesting that excess iodine exposure in the NICU could be causing CH. It may be beneficial to monitor iodine exposure from surgical procedures, imaging, and iodine-containing disinfectants and to consider non-iodine alternatives.

Congenital Hypothyroidism in Children - A Cross-Sectional Study in a Tertiary Centre in Malaysia

Introduction

The causes of congenital hypothyroidism (CHT) are thyroid dysgenesis (TD), dyshormonogenesis (TDH) or transient hypothyroidism (TH).

Methodology

This is a cross-sectional study looking at data over a period of 16 years (2000-2016). Confirmed cases had thyroid scan at the age of 3-years-old and repeated TFT (after 6 weeks off medications). Relevant data was collected retrospectively.

Results

Forty (60% female) children with CHT were included in the study. Thirty (75%) children presented with high cord TSH. Nine (23%) presented after 2 weeks of life. Majority were diagnosed with TDH (42.5%) with TD and TH of 40% and 17.5% respectively. Median cord TSH of children with TD was significantly higher compared to TDH and TH (p=0.028 and p=0.001 respectively). L-thyroxine doses were not significantly different between TD, TDH and TH at diagnosis or at 3 years.

Conclusions

TDH is highly prevalent in our population. TD may present after 2 weeks of life. One in five children treated for CHT had TH. Differentiating TD, TDH and TH before initiating treatment remains a challenge in Malaysia. This study provides clinicians practical information needed to understand the possible aetiologies from a patient’s clinical presentation, biochemical markers and treatment regime. Reassessing TH cases may be warranted to prevent unnecessary treatment.

Effect of delayed diagnosis and treatment of congenital hypothyroidism on intelligence and quality of life: an observational study

BACKGROUND Congenital hypothyroidism is one of the most prevalent, albeit preventable causes of intellectual disability. This study determined the intellectual outcome and health-related quality of life (QoL) in children and adolescents clinically diagnosed with congenital hypothyroidism and the associations among age of starting thyroid hormone treatment, current free thyroxine (FT4) level, intelligence quotient (IQ), and QoL.METHODS Intelligence (Wechsler scales) and QoL (PedsQLTM 4.0 parent proxy-report) tests were administered to 25 patients with congenital hypothyroidism in the pediatric clinic of Cipto Mangunkusumo Hospital, Jakarta. Nineteen patients underwent thyroid ultrasonography or scintigraphy to determine the etiology of congenital hypothyroidism.RESULTS A total of 25 patients with the median age of 9 (5.5–12.5) years were recruited. Eighteen patients had a total IQ of <70. The age of treatment initiation did not correlate with full scale IQ (FSIQ) (r = −0.261, p = 0.071) and verbal IQ (VIQ) (r = −0.232, p = 0.265). The late initiation of treatment was correlated with lower performance IQ (PIQ) (r = −0.325, p = 0.025). The higher current FT4 levels was correlated with higher scores ofFSIQ (r = 0.314, p = 0.046) and PIQ (r = 0.320, p = 0.043). The late initiation of treatment (r = 0.006, p = 0.980) and higher current FT4 levels (r = 0.246, p = 0.310) were not correlated with QoL. Hemiagenesis of thyroid gland was the most common etiology.CONCLUSIONS The late initiation of thyroid hormone substitution in patients with congenital hypothyroidism negatively affects intellectual abilities.

Effects of PM2.5 and PM10 on congenital hypothyroidism in Qingdao, China, 2014-2017: a quantitative analysis

BACKGROUND

We aimed to quantify the impact of PM_2.5 and PM₁₀ pollution on congenital hypothyroidism (CH) in Qingdao in the period 2014-2017.

METHODS

A generalized additive mixed model (GAMM) with time-series Poisson regression was conducted to quantify the association between PM_2.5 and PM₁₀ variables in the month when cases of CH were born or in the two preceding the months (lag0, lag1 and lag2) and monthly morbidity of people with CH across different populations.

RESULTS

A total of 480,633 newborns were screened for CH during 2014-2017 in Qingdao, and there were 268 cases of CH diagnosed. The count of days per month for which average concentrations of PM_2.5 and PM₁₀ exceed legal limits were positively associated with monthly CH morbidity at lag1 month among all the populations, and the adjusted relative risks (RRs) with exposure per 10 μg/m³ were close among different populations. However, the number of days per month of PM_2.5 and PM₁₀ concentrations exceeding limits were negatively associated with CH morbidity. Additionally, the RRs of CH increase with worsening air pollution.

CONCLUSIONS

Concentrations of PM_2.5 and PM₁₀ exceeding the legal limits are significantly associated with CH in Qingdao. Moreover, it suggests that sudden and short-term particulate matter pollution events with high levels of particulates exceeding the legal limits may be related to risk of CH.

Neonatal screening in the Czech Republic: increased prevalence of selected diseases in low birthweight neonates

Neonates with low birthweight (LBW) represent a vulnerable population. This retrospective study analyzed the birth frequency of diseases detected by neonatal screening (NBS) in normal and LBW neonates in the Czech Republic. Between years 2002 and 2016, the number of screened disorders in the Czech Republic gradually increased from two to 13. Prevalence of screened diseases was calculated for cohorts ranging from 777,100 to 1,277,283 neonates stratified by birthweight. Odds ratio of the association of LBW with each disease was calculated and statistical significance was evaluated using the chi-square test or Fisher's exact test, as appropriate. Three diseases were associated with higher risk of prevalence in LBW neonates, namely congenital hypothyroidism (OR 2.50, CI 1.92; 3.25), cystic fibrosis (OR 2.44, CI 1.51; 3.94), and long chain 3-hydroxyacyl-CoA dehydrogenase deficiency (LCHADD) (OR 7.74, CI 2.18; 27.42).Conclusion: Although the underlying mechanisms are not well understood, results can be hypothesized that LBW (respectively prematurity) may lead to the secondary and often transitory hypothyroidism while cystic fibrosis and LCHADD may manifest already prenatally and result into preterm birth and LBW. What is Known: • The percentage of low birthweight (LBW) neonates in the Czech Republic has been increasing. • Previously published studies reported positive association between LBW and congenital hypothyroidism and cystic fibrosis. What is New: • The association between LCHADD and LBW has not yet been described. • LBW can be the first manifestation of cystic fibrosis and LCHADD.

Phonological acquisition in children with early-treated congenital hypothyroidism: association with clinical and laboratory parameters

PURPOSE

To evaluate the phonological characteristics of children with congenital hypothyroidism (CH).

METHODS

Observational, analytical, cross-sectional, ambispective study including prepubertal children with CH (n=100; study group, SG) and controls without CH ( n=100; control group, CG). Assessments included a speech language pathology interview, the phonological evaluation of the ABFW Child Language Test, medical data, and neuropsychological tests in the first three years of life.

RESULTS

On treatment onset of the SG, the median chronological age of the participants was 18.0 days and 48.4% had total T4 <2.5 µg/dL (31.75 nmol/L). At the age of 7 years, children in the SG had higher rates of consonant cluster simplification and lower rates of complete phonological system compared to those in the CG. On analysis of combined age groups (4+5 and 6+7 years), the CG had a higher frequency of complete acquisition versus the SG. On multivariate analysis, thyroid agenesis, abnormal scores on the Clinical Linguistic and Auditory Milestone Scale and developmental quotient tests were associated with the occurrence of phonological disorders.

CONCLUSION

Children with CH present delay in phonological acquisition, despite early diagnosis and adequate treatment, especially between the ages of 6-7 years. The etiology of CH and the results of neuropsychological tests in the first years of life seem to be related to this delay.

Assessment of knowledge, attitudes and practices towards newborn screening for congenital hypothyroidism before and after a health education intervention in pregnant women in a hospital setting in Pakistan

Background

Most congenital hypothyroidism (CH) is not avertable; however, the adverse effects of CH are preventable with early detection and treatment. It is a common congenital endocrine disorder that affects 1 in 2000-4000 newborns globally. The true incidence in Pakistan is unknown. Data from hospital studies quote an incidence of 1 in 1600-2000. The aim of this study was to uncover existing knowledge of CH and screening for the condition and to assess the impact of health education on mothers' knowledge and attitudes towards having their newborns screened.

Methods

The study was conducted from January 2012 to August 2013 at a local hospital in Karachi, Pakistan. This was a prospective, interventional cohort study implemented through a pre- and post-cross-sectional knowledge, attitudes and practices (KAP) survey. Interviews were conducted using structured questionnaires on CH.

Results

At baseline (pre-intervention survey), 400 participants consented and 355 (88.9%) completed the study. There was a significant increase in awareness among participating women following the intervention (20% to approximately 98%). Similarly, 78.9% agreed to opt for a screening test for their newborns following delivery as compared with 57.7% in the pre-intervention KAP survey (relative risk 1.38, p-value <0.0001).

Conclusion

Unfortunately, the majority of mothers were unaware of CH and its implications, leading to less screening and fewer diagnoses. This study underlines the importance of education in screening programmes to create awareness and maximize uptake.

Incidence of congenital hypothyroidism in China: data from the national newborn screening program, 2013-2015

BACKGROUND

Congenital hypothyroidism (CH) is one of the most frequent, preventable causes of mental retardation. Little has been reported on the epidemiological characteristics of CH in China. We aimed to estimate the incidence of CH in China and investigate its geographical variation.

METHODS

We analyzed data from the nationwide newborn screening program for CH between 2013 and 2015. Poisson regression was used to generate the odds ratios (ORs) and 95% confidence intervals (CIs) between the rates of CH and selected demographic characteristics and assess the potential association between CH incidence and geographical locations.

RESULTS

A total of 18,666 patients with CH were identified from 45.2 million newborns, yielding an overall incidence rate of 4.13 per 10,000 live births. Compared with those in the remote area, regardless of infant sex, a higher incidence risk for CH was present in newborns in coastal areas and inland areas (females: OR=2.00, 95% CI: 1.86-2.16 and OR=1.74, 95% CI: 1.61-1.87, respectively; males: OR=1.70, 95% CI: 1.59-1.83 and OR=1.52, 95% CI: 1.42-1.63, respectively). Additionally, the highest risk of CH for thyroid-stimulating hormone (TSH) screening values <40 mU/L was observed among neonates in the coastal areas, while TSH screening values of 70-100 mU/L were observed among those in the inland areas.

CONCLUSIONS

The overall incidence of CH is high in China. The significant geographical variations of CH incidence are presented in this study.

Are lower TSH cutoffs in neonatal screening for congenital hypothyroidism warranted?

When newborn screening (NBS) for congenital hypothyroidism (CH) using thyroid-stimulating hormone (TSH) as a primary screening test was introduced, typical TSH screening cutoffs were 20-50 U/L of whole blood. Over the years, lowering of TSH cutoffs has contributed to an increased prevalence of detected CH. However, a consensus on the benefit deriving from lowering TSH cutoffs at screening is lacking. The present paper outlines arguments both for and against the lowering of TSH cutoffs at NBS. It includes a review of recently published evidence from Australia, Belgium and Italy. A section focused on economic implications of lowering TSH cutoffs is also provided. One issue that bears further examination is the extent to which mild iodine deficiency at the population level might affect the association of neonatal TSH values with cognitive and developmental outcomes. A debate on TSH cutoffs provides the opportunity to reflect on how to make NBS for CH more effective and to guarantee optimum neurocognitive development and a good quality of life to babies with mild as well as with severe CH. All authors of this debate article agree on the need to establish optimal TSH cutoffs for screening programs in various settings and to ensure the benefits of screening and access to care for newborns worldwide.

Vocal Evaluation of Children with Congenital Hypothyroidism

OBJECTIVE

To evaluate the vocal characteristics of a group of children with congenital hypothyroidism (CH) and the association of these characteristics with the children's clinical, laboratory, and therapeutic profiles.

MATHERIAL AND METHODS

Observational, analytical, cross-sectional study including 200 prepubertal children, of whom 100 had CH (study group [SG]) and 100 had no CH (control group [CG]). The following parameters were evaluated: 1) history (identification, complaints, and interfering variables), 2) auditory-perceptual and acoustic evaluation (samples analyzed by a group of specialists, and objectively by a computer program), 3) self-assessment scores in the Pediatric Voice-Related Quality-of-Life (PVRQoL) survey, 4) laryngological evaluation (presence or absence of laryngeal lesions and data regarding glottal closure), and 5) medical records (CH etiology, age at treatment initiation, disease severity at diagnosis, treatment quality, and thyroid function tests on the day of the examination).

RESULTS

In the perceptual assessment, 62.6% of the SG children passed, whereas 37.4% failed in the voice screening, but these results were comparable with those in the CG (P = 0.45). Both groups had mean/median acoustic measurements within the normal limits. The mean PVRQoL in the SG (99.3 ± 2.4) and CG (99.5 ± 1.7) were comparable (P = 1.00). Both SG (16.7%) and CG (15%) presented vocal cord lesions (P = 1.00). There was no association between voice/larynx characteristics and endocrinological data.

CONCLUSION

Prepubescent children diagnosed with CH during neonatal screening and who have a lifelong history of adequate treatment of CH showed similar vocal and laryngeal characteristics compared with children without CH.

Neonatal screening parameters in infants with congenital Cytomegalovirus infection

Congenital Cytomegalovirus infection (cCMV) is the most common cause of congenital infections worldwide that can cause long-term impairment (LTI). The metabolic alterations due to cCMV are largely unknown. This study aims to assess the metabolites included in the neonatal screening in relation to cCMV and cCMV outcome, allowing the identification of prognostic markers for clinical outcome. Essential amino acids, hormones, carnitines and enzymes from Dried Blood Spots (DBS) were analyzed of 102 children with cCMV and 179 children without cCMV, and they were related to symptoms at birth and LTI at 6years of age. In this cohort, the neonatal screening parameters did not change in relation to cCMV, nor to symptoms at birth or LTI. However, metabolic changes were observed in children born preterm, with lower concentrations of essential amino acids in premature infants with cCMV compared to premature controls. Finally, a higher concentration of palmytoilcarnitine (C16) in the group with higher viral load was observed. Though these data demonstrate limitations in the use of neonatal screening data as predictors for long-term cCMV outcome, the metabolism of preterm neonates with cCMV merits further evaluation.

The incidence of congenital hypothyroidism and its determinants from 2012 to 2014 in Shadegan, Iran: a case-control study

OBJECTIVES:

Congenital hypothyroidism (CH) is one of the major causes of preventable mental retardation in infants. The aim of this study was to determine the incidence of CH in Shadegan, Khuzestan Province, Iran from 2012 to 2014 and to identify the risk factors associated with CH.

METHODS:

A total of 203 cases were confirmed from 2012 to 2014 in Shadegan, with 66, 86, and 51 patients reported in 2012, 2013, and 2014, respectively. A total of 3,900, 3,991, and 4,050 live births occurred in 2012, 2013, and 2014, respectively. The controls (n=657) were selected using a random number table, and a case-control study was carried out to determine the risk factors for neonatal CH, including demographic, environmental, and medical factors.

RESULTS:

The incidence of CH was 17.0 per 1,000 live births in 2012, 21.5 per 1,000 live births in 2013, and 12.6 per 1,000 live births in 2014. This study showed that the likelihood of CH in children born to parents with a history of consanguineous marriage was 2.41 times greater than in children born to parents with no such history (odds ratio, 2.41; 95% confidence interval [CI], 1.65 to 3.53). This study also found that CH was 3.4 times more likely (95% CI, 2.29 to 5.20) in infants born in urban settings than in infants born in rural areas.

CONCLUSIONS:

The incidence of CH in Shadegan from 2012 to 2014 was approximately 17 times greater than the expected incidence in Iran. CH was associated with a history of consanguineous marriage and urbanization.

Reference intervals for thyroid stimulating hormone and free thyroxine derived from neonates undergoing routine screening for congenital hypothyroidism at a university teaching hospital in Nairobi, Kenya: a cross sectional study

BACKGROUND

In order to accurately interpret neonatal thyroid function tests (TFTs), it is necessary to have population specific reference intervals (RIs) as there is significant variation across different populations possibly due to genetic, environmental or analytical issues. Despite the importance of RIs, globally there are very few publications on RIs for neonatal TFTs primarily due to ethical and technical issues surrounding recruitment of neonates for a prospective study. To the best of our knowledge, this is the first report from Africa on neonatal RIs for TFTs.

METHODS

We used hospital based data largely derived from neonates attending the wellness clinic at the Aga Khan University Hospital Nairobi (AKUHN) where screening for congenital hypothyroidism is routinely done. Specifically we derived age and gender stratified RIs for free thyroxine (fT4) and thyroid stimulating hormone (TSH) which had been analyzed on a Roche e601 analyzer from 2011 to 2013. Determination of reference intervals was done using a non-parametric method.

RESULTS

A total of 1639 and 1329 non duplicate TSH and fT4 values respectively were used to derive RIs. There was a decline in TSH and fT4 levels with increase in age. Compared to the Roche RIs, the derived RIs for TSH in neonates aged 0-6 days and those aged 7-30 days had lower upper limits and narrower RIs. The fT4 lower limits for neonates less than 7 days and those aged 7-30 days were higher than those proposed by Roche. There was a significant difference in TSH RIs between male and female neonates aged less than 15 days. No gender differences were seen for all other age stratifications for both TSH and fT4. Appropriate age and gender specific RIs were subsequently determined.

CONCLUSION

The AKUHN derived RIs for fT4 and TSH revealed similar age related trends to what has been published. However, the differences seen in upper and lower limits across different age stratifications when compared to the Roche RIs highlight the need for population specific RIs for TFTs especially when setting up a screening programme for congenital hypothyroidism. We subsequently recommend the adoption of the derived RIs by the AKUHN laboratory and hope that the RIs obtained can serve as a reference for the African population.

Oxidative stress, thyroid dysfunction & Down syndrome

Down syndrome (DS) is one of the most common chromosomal disorders, occurring in one out of 700-1000 live births, and the most common cause of mental retardation. Thyroid dysfunction is the most typical endocrine abnormality in patients with DS. It is well known that thyroid dysfunction is highly prevalent in children and adults with DS and that both hypothyroidism and hyperthyroidism are more common in patients with DS than in the general population. Increasing evidence has shown that DS individuals are under unusual increased oxidative stress, which may be involved in the higher prevalence and severity of a number of pathologies associated with the syndrome, as well as the accelerated ageing observed in these individuals. The gene for Cu/Zn superoxide dismutase (SOD1) is coded on chromosome 21 and it is overexpressed (~50%) resulting in an increase of reactive oxygen species (ROS) due to overproduction of hydrogen peroxide (H₂O₂). ROS leads to oxidative damage of DNA, proteins and lipids, therefore, oxidative stress may play an important role in the pathogenesis of DS.

Single newborn screen or routine second screening for primary congenital hypothyroidism

Routine second screening of most newborns at 8-14 days of life for a panel of newborn conditions occurs in 12 U.S. states, while newborns in the other states typically undergo only a single routine newborn screen. The study objective was to evaluate screening consequences for primary congenital hypothyroidism (CH) in one- and two-screen states according to laboratory practices and medical or biochemical characteristics of screen-positive cases. Individual-level medical and biochemical data were retrospectively collected and analyzed for 2251 primary CH cases in one-screen (CA, WI) and two-screen (AL, DE, MD, OR, TX) states. Aggregate data were collected and analyzed for medical and biochemical characteristics of all screened newborns in the states. Among the states evaluated in this study, the detection rate of primary CH was higher in the one-screen states. In the two-screen states, 11.5% of cases were detected on the second screen. In multivariate analyses, only race/ethnicity was a significant predictor of cases identified on the first versus second screen, which likely reflects a physiologic difference in primary CH presentation. Newborn screening programs must heed the potential for newborns with CH not being detected by a single screen, particularly newborns of certain races/ethnicities. If the two-screen states converted to a single screen using their current algorithms, newborns currently identified on the routine second screen would presumably not be detected, resulting in probable delayed diagnosis and treatment. However, based on the one-screen state experiences, with appropriate modifications in screening method and algorithm, the two-screen states might convert to single screen operation for CH without loss in performance.

Using record linkage to investigate perinatal factors and neonatal thyroid-stimulating hormone

AIM

Studies examining the relationship between maternal and infant thyroid parameters have shown conflicting results. Record linkage provides an opportunity to examine the association between maternal and infant thyroid-stimulating hormone (TSH) levels. Our aim was to demonstrate the feasibility of record linkage of newborn screening (NBS), laboratory and birth databases for research by investigating the association between maternal and newborn TSH levels.

METHODS

The records of 2802 women with first trimester serum TSH concentrations were linked with population-based birth data and NBS data containing infant TSH levels. Association between moderately high neonatal TSH levels (>5 mIU/L) and maternal and infant characteristics was evaluated. The correlation and association between maternal and infant TSH levels were assessed using Pearson's correlation coefficient and multivariable linear regression, respectively.

RESULTS

Of maternal and birth records, 99.3% linked with an NBS record. Mother's country of birth, gestational age (>41 weeks) and lower birthweight were associated with neonatal TSH levels >5 mIU/L. Neonatal and maternal first trimester TSH levels were not correlated, although statistically significant (r = 0.05, P = 0.008). The association between neonatal TSH and maternal TSH, after adjusting for maternal age, gestational age and age at NBS testing, was also small (b = 0.039, P = 0.009).

CONCLUSIONS

Record linkage is a feasible and cost-efficient way to investigate the association between maternal factors and neonatal hormone levels. First trimester maternal thyroid levels are not correlated with neonatal TSH levels. This method of outcome assessment can be used for future research examining long-term outcomes for infants with different NBS results.

Clinical practice: experience with newborn screening for congenital hypothyroidism in the Republic of Macedonia - a multiethnic country

To evaluate the thyroid screening program and to estimate the prevalence of congenital hypothyroidism (CH) among newborns in the Republic of Macedonia, we measured thyroid-stimulating hormone (TSH) levels in dried blood spot specimens using the DELFIA fluoroimmunoassay, over a period of 12 years. The TSH cutoff level was 10 mU/L blood. A total of 215,077 newborns were screened (94.76 %). Out of 254 recalled newborns (a recall rate of 0.15 %), 83 newborns with CH were detected, yielding a CH prevalence at screening of 1/2,591 (female to male ratio, 1.86:1). Of the CH cases, 47/107,754 (56.6 %) neonates were Macedonian, 29/70,330 (34.9 %) were Albanian, and 7/15,055 (8.4 %) were Roma. The thyroid gland was undetectable on ultrasound in 43 (51.8 %) newborns with CH, thyroid hypoplasia was confirmed in 8 (9.6 %), while 29 (34.9 %) had a normal thyroid gland. In three newborns (3.6 %), agenesis of one lobe was confirmed. Therapy with levothyroxin was initiated on average 11.7 days after birth.

CONCLUSION

The national thyroid newborn screening program in Macedonia has been successful and effective, providing timely diagnosis and treatment of children with congenital hypothyroidism.

Congenital hypothyroidism

Congenital hypothyroidism (CH) is the one of the most common preventable cause of mental retardation. In the majority of patients, CH is caused by an abnormal development of the thyroid gland (thyroid dysgenesis) that is a sporadic disorder and accounts for 85% of cases and the remaining 15% of cases are caused by dyshormonogenesis. The clinical features of congenital hypothyroidism are so subtle that many newborn infants remain undiagnosed at birth and delayed diagnosis leads to the most severe outcome of CH, mental retardation, emphasizing the importance of neonatal screening. Dried capillary blood is used for screening and it is taken from heel prick optimally between 2 and 5 days of age. Blood spot TSH or thyroxine (T4) or both are being used for CH screening in different programs around the world. Neonates with abnormal thyroid screening tests should be recalled immediately for examination and a venipuncture blood sample should be drawn for confirmatory serum testing. Confirmatory serum should be tested for TSH and free T4, or total T4. Serum TSH and T4 undergo dynamic changes in the first weeks of life; it is important to compare serum results with age-normal reference ranges. Treatment should be started promptly and infant should be rendered euthyroid as early as possible, as there is an inverse relationship between intelligence quotient (IQ) and the age at diagnosis. Levothyroxine (l-thyroxine) is the treatment of choice and American academy of pediatrics and European society of pediatric endocrinology recommend 10-15μgm/kg/day as initial dose. The immediate goal of therapy is to normalize T4 within 2 weeks and TSH within one month. The overall goal of treatment is to ensure growth and neurodevelopmental outcomes as close as possible to their genetic potential.

Gender-based differences in pediatric nuclear medicine

Gender-based differences commonly encountered in pediatric nuclear medicine reflect both basic embryologic differences of the sexes, which are evident from infancy, and evolving physiological changes due to gender, which occur as the pediatric patient grows, undergoes puberty, and matures to adulthood. It is important for a nuclear medicine physician or radiologist to know both the gender and the age of a patient when interpreting her or his studies. It is also important that the reading physician be familiar with the normally evolving physiological changes that are specific for that patient's stage of development. It is particularly important that the reading physician consider such changes when comparing serial studies of the patient that are acquired during the patient's transitions through her or his different significant stages of development. Many pediatric nuclear medicine imaging protocols are modifications or adaptations of the protocols for adult imaging. Physicians reading pediatric studies must routinely incorporate knowledge on age and gender that is relevant to the patient for any given study. The age-defined gender-based subtleties of potential findings in pediatric nuclear medicine studies are often underrecognized. However, they are often of interest and at times important in the workup of both benign entities and pathologic processes of the pediatric patient.

Agenesis and not ectopia is common in North Indian children with thyroid dysgenesis

CONTEXT

Ectopic Thyroid Gland (ETG) is known to be the most common form of thyroid dysgenesis in children with permanent congenital hypothyroidism (CH). Recent reports indicate that agenesis or hypoplasia of thyroid gland may be commoner as compared to ETG in thyroid dysgenesis (TD). There is limited information available on the proportion of different variants of TD in Indian children.

AIM

To characterize the different TD variants in a cohort of North Indian children with TD.

SETTINGS AND DESIGN

Endocrinology Unit of a large Multispecialty Pediatrics Center located in North India. Retrospective review of clinical records of children with CH due to TD diagnosed between April 2004 and March 2014.

RESULTS

Diagnoses of TD in 94 children (48 boys and 46 girls) were based on combined scanning with high-resolution ultrasonography, and technetium-99m pertechnetate thyroid scintigraphy. Thyroid agenesis, ectopia and hypoplasia were diagnosed in 74 (78.7%), 14 (14.8%) and 6 (6.4%) patients respectively. The mean initial serum total T4 and thyroid stimulating hormone concentrations at diagnosis were 3.03 ± 2.88 μg/dL (range 0.01-8.9) and 284.52 ± 300.67 mIU/L (range 10.03-1159.0) respectively. Patients with ETG were older at the time of diagnosis as compared to patients with hypoplasia or ectopia. The mean duration of follow-up was 3.7 ± 2.85 years (range 3 months-10 years).

CONCLUSIONS

Thyroid agenesis was the most common form of TD in our children with permanent CH. Hypoplasia and ectopia were uncommon. Female preponderance, noted in many previous reports, was not seen in our patients with TD.

Aneuploidy and skeletal health

The normal human chromosome complement consists of 46 chromosomes comprising 22 morphologically different pairs of autosomes and one pair of sex chromosomes. Variations in either chromosome number and/or structure frequently result in significant mental impairment and/or a variety of other clinical problems, among them, altered bone mass and strength. Chromosomal syndromes associated with specific chromosomal abnormalities are classified as either numerical or structural and may involve more than one chromosome. Aneuploidy refers to the presence of an extra copy of a specific chromosome, or trisomy, as seen in Down's syndrome (trisomy 21), or the absence of a single chromosome, or monosomy, as seen in Turner syndrome (a single X chromosome in females: 45, X). Aneuploidies have diverse phenotypic consequences, ranging from severe mental retardation and developmental abnormalities to increased susceptibility to various neoplasms and premature death. In fact, trisomy 21 is the prototypical aneuploidy in humans, is the most common genetic abnormality associated with longevity, and is one of the most widespread genetic causes of intellectual disability. In this review, the impact of trisomy 21 on the bone mass, architecture, skeletal health, and quality of life of people with Down syndrome will be discussed.

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

BACKGROUND AND OBJECTIVES

Although 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 SETTINGS

This 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.

METHODS

This 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.

RESULTS

A 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.

CONCLUSION

Our 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.

Hipotireoidismo congênito: recomendações do Departamento de Tireoide da Sociedade Brasileira de Endocrinologia e Metabologia

O hipotireoidismo congênito (HC) é o distúrbio endócrino congênito mais frequente, com incidência variando de 1:2.000 a 1:4.000 crianças nascidas vivas e uma das principais causas de retardo mental que pode ser prevenida. Os Programas de Triagem Neonatal para a doença permitem a identificação precoce dos afetados e seu tratamento de modo a evitar as complicações da falta do hormônio. A maioria dos casos de hipotireoidismo congênito é decorrente de disgenesias tireoidianas (85%), entre elas a ectopia, hipoplasia ou agenesia tireoidianas, e os demais resultam de defeitos de síntese hormonal. As crianças afetadas (> 95%) geralmente não apresentam sintomas sugestivos da doença ao nascimento. Os sintomas e sinais mais comuns são: icterícia neonatal prolongada, choro rouco, letargia, movimentos lentos, constipação, macroglossia, hérnia umbilical, fontanelas amplas, hipotonia e pele seca. Várias estratégias são utilizadas para a triagem do HC. No Brasil, esta é obrigatória por lei e geralmente é feita com a dosagem de TSH em sangue seco coletado do calcanhar. A idade recomendada para sua realização é após as 48 horas de vida até o quarto dia. A confirmação diagnóstica é obrigatória com as dosagens de TSH e T4 livre ou T4 total.

Congenital hypothyroidism after assisted reproductive technology in Japan: comparison between multiples and singletons, 2005-2009

Background

The relationship between congenital hypothyroidism (CH) and multiple pregnancy has not been fully studied in Japan.

Methods

Complete nationwide data of assisted reproductive technology (ART) in Japan from 2005 to 2009 presented by the Japan Society of Obstetrics and Gynecology, which include information on CH and birth defects were used for analyses. Diseases were reclassified according to the International Classification of Diseases, tenth edition (ICD-10, 2003 version). The relative risk (RR) and 95% confidence interval (CI) of the incidence rate for CH was calculated with singletons as the reference group. Additional birth defects with CH were examined. The probandwise concordance rate of multiples and recurrence risk ratio were calculated.

Results

There were 18 patients with CH, consisting of 12 singletons and 6 multiples. The incidence rates of CH per 1,000 live births in singletons and multiples are 0.14 (=12/87,145) and 0.31 (=6/19,533), respectively. The incidence rate was more than twofold higher in multiple births than in singleton births, but the difference was not statistically significant (RR=2.2, 95% CI 0.8–5.9). Additional birth defects were present in three patients with CH (17%=3/18). The multiples were affected by other birth defects more frequently (33%=2/6) than the singletons (8%=1/12). The six multiple-births patients were derived from one concordant twin pair, which consisted of two twin patients; three discordant twin pairs, which consisted of three twin patients; and one discordant triplets set, which consisted of one triplet patient. Thus, the probandwise concordance rate was 33.3% (=2/(2+4)). The estimated recurrence risk ratio was 1976 (for the total ART population) or 609 (for the Japanese general population).

Conclusions

CH was more frequent in multiples compared to singletons. A higher percentage of additional birth defects was also observed in multiples compared to singletons. The familial aggregation of CH was suggested.

Diagnosed congenital hypothyroidism with missing follow-up: is it time for a national registry?

A treatable and preventable disorder, congenital hypothyroidism (CH) is still a common cause of mental retardation. A 17-year-old Saudi boy with CH due to an ectopic thyroid gland was diagnosed by the neonatal screening program.Thyroxine replacement therapy was started for one month when the family chose to discontinue medication and follow-up. He was not then seen until 11 years of age. Thyroxine was restarted with a close follow-up, although thyroid function tests gradually improved back to normal levels, but his final height was short (159 cm) and IQ was negatively affected. Despite the diagnosis having been made at an appropriate time, patient was lost to follow up. This indicates an obvious flaw in the system for follow-up care. We recommend a registry of patients with CH to monitor their care. The aim of such a registry would be to monitor the efficiency and efficacy of neonatal screening.

Neonatal screening for congenital hypothyroidism in East Azerbaijan, Iran: the first report

Objectives

To investigate the prevalence of congenital hypothyroidism (CH) among neonates in East Azerbaijan, Iran.

Methods

A cross-sectional study conducted from 2009 to 2010. Most heel blood samples were taken between three and seven days of birth. Thyroid stimulating hormone (TSH) was tested using the enzyme-linked immunosorbent assay method. Neonates with abnormal screening results (TSH>20 mIU/L, T4<6.5 mg/dL) were re-examined. Data were analysed using SPSS software.

Results

A total of 62,459 infants were screened. Of 1562 re-called subjects (re-call rate 2.5%), 94 cases with CH were detected, yielding a CH prevalence of 1:666 (female:male ratio 1:1.4).

Conclusion

The prevalence of CH in East Azerbaijan province is higher in comparison with worldwide levels. These results emphasize the importance of the neonatal screening programme.

Birth prevalence of disorders detectable through newborn screening by race/ethnicity

PURPOSE

The purpose of this study was to describe the birth prevalence of genetic disorders among different racial/ethnic groups through population-based newborn screening data.

METHODS

Between 7 July 2005 and 6 July 2010 newborns in California were screened for selected metabolic, endocrine, hemoglobin, and cystic fibrosis disorders using a blood sample collected via heel stick. The race and ethnicity of each newborn was self-reported by the mother at the time of specimen collection.

RESULTS

Of 2,282,138 newborns screened, the overall disorder detection rate was 1 in 500 births. The disorder with the highest prevalence among all groups was primary congenital hypothyroidism (1 in 1,706 births). Birth prevalence for specific disorders varied widely among different racial/ethnic groups.

CONCLUSION

The California newborn screening data offer a unique opportunity to explore the birth prevalence of many genetic disorders across a wide spectrum of racial/ethnicity classifications. The data demonstrate that racial/ethnic subgroups of the California newborn population have very different patterns of heritable disease expression. Determining the birth prevalence of these disorders in California is a first step to understanding the short- and long-term medical and treatment needs faced by affected communities, especially those groups that are impacted by more severe disorders.

Review of primary hypothyroidism in very low birthweight infants in a perinatal centre in Hong Kong

AIMS

To review the incidence and risk factors of primary hypothyroidism in very low birthweight (VLBW) infants in our centre and to assess their neurodevelopmental outcome.

METHOD

Retrospective, descriptive review of VLBW infants with primary hypothyroidism from 1 January 2000 to 31 December 2008 in a perinatal centre. Case control comparisons for neurodevelopmental outcome at 18 months, nested to a prospective VLBW cohort (Vermont Oxford Database).

RESULTS

Twelve cases were identified, with the incidence of primary hypothyroidism of 1 in 55 live births in our VLBW cohort during the 9-year study period. Umbilical cord blood thyroid-stimulating hormone was abnormal in less than half of the cases using the current cut-off (≤14 mIU/L). Five cases were transient in nature, four cases were permanent and the causes for the rest remained undetermined at the time of review. Elevation of thyroid-stimulating hormone was first evident at a mean of 2.4 weeks post-natally. Follow-up assessment reviewed normal development in 83% of cases (10 out of 12 cases). There was no statistically significant difference in Griffith's scores at 18 months between the case and matched controls.

CONCLUSIONS

The high incidence of primary hypothyroidism in our VLBW cohort deserved stringent monitoring of thyroid function post-natally. Umbilical cord blood screening was not useful as a screening tool because of its low sensitivity. Neurodevelopmental outcome for treated primary hypothyroidism was favourable as assessed at 18 months of age.

[Endocrinological abnormalities in 1,105 children and adolescents with Down syndrome]

BACKGROUND AND OBJECTIVE

Children and adolescents with Down syndrome (DS) show a greater prevalence of endocrinological abnormalities when compared with the general population. Our aim is to analyze endocrinological abnormalities in 1,105 patients with DS.

PATIENTS AND METHODS

A review of 1,105 cases of children and adolescents with DS under care in our Department (ages between 0 and 18 years) analyzed retrospectively the presence of thyroid pathology and diabetes mellitus throughout development.

RESULTS

Our data indicate the presence of endocrinological abnormalities in 222 patients [216 with thyroid pathology (19.5%) and 6 cases with diabetes mellitus type 1 (0.45%)]. Subclinical primary hypothyroidism was present in 168 cases, congenital primary hypothyroidism in 15 cases, clinical primary hypothyroidism in 24 cases and 5 cases had hyperthyroidism. In addition, 16.9% of these patients exhibit criteria of obesity and 28.2% had overweight. The prevalence of endocrinological comorbidities in children and adolescents with DS is higher than in the general population.

CONCLUSION

Subclinical primary hypothyroidism, due to autoimmune causes in most of the patients, without a higher incidence in females, is the most common endocrinological pathology associated with DS. The high frequency of thyroid pathology and diabetes mellitus type 1 in these patients should induce us to have a closer clinical control of children and adolescents with DS.

Primary blood TSH/back up TSH measurements: an improved approach for neonatal thyroid screening

OBJECTIVE

Neonatal hypothyroidism is one of the most common endocrine disorders related to mental impairment and growth retardation in newborns. In many countries, the neonatal thyroid screening programs are performed for rapid diagnosis and treatment of hypothyroidism. The major aim of this investigation was to improve the thyroid screening program using primary blood TSH/back up TSH measurements as some patients are missed due to technical and human errors.

METHODS

A total of 9,118 neonates were evaluated on the protocol. On top of that, the quality control procedures were applied to improve the sampling technique and the laboratory results.

RESULTS

Three missed neonates by current programs using the cutoff point more than 20  mU/l for blood TSH were found by our approach.

CONCLUSION

Results showed that the programs based on the primary blood TSH/back up TSH measurements improve the thyroid screening results.

Effect of temperature changes on the occurrence of congenital hypothyroidism

OBJECTIVES

To investigate an association between seasonal changes in temperature and the prevalence of congenital hypothyroidism (CH) in the Southwest of Iran.

METHODS

A prospective two-year study conducted from March 2007 to March 2009 during the nationwide screening programme for CH in Ahvaz, the biggest city in southwest Iran. Blood samples were taken from almost all newborns by heel-stick and used in a thyroid-stimulating hormone (TSH)-enzyme-linked immunosorbent assay (ELISA). Serum thyroxine (T4) and TSH were measured if the ELISA-TSH was >5 mIU/L (suspicious cases). Infants were considered to have CH with T4 <6.0 µg/dL and TSH > 10 mIU/L, or with normal T4 values and persistent high TSH values for >2 months (subclinical hypothyroidism). Date of birth and sex were recorded. Detailed temperature data were obtained from the meteorological organization. The relationship between the monthly incidence of CH and the average monthly temperature was investigated.

RESULTS

From 47,075 (50.92% male) newborns, 1131 were referred (recall rate = 2.4%) and 142 infants (51.4% male) were confirmed to have CH. The seasonal distribution of CH cases was 32.4% in the warm period and 67.6% in the cold period of the year (19%, 13.4%, 32.4% and 35.2% in spring, summer, fall and winter, respectively; P = 0.001). A statistical difference was seen between mid-summer (2.8%, warmest time) and early winter (15.5%, coldest time). The above-mentioned difference was the same for suspicious individuals (P < 0.001). The odds of being affected were increased by 4% for each fall of 1°C.

CONCLUSION

The prevalence of CH has a significant negative correlation with the temperature in the tropical area of Iran.

Variation by ethnicity in the prevalence of congenital hypothyroidism due to thyroid dysgenesis

BACKGROUND

The scant data on ethnic differences in the prevalence of congenital hypothyroidism (CH) have generally not taken etiology of CH into account. Our hypothesis is that the prevalence of CH due to thyroid dysgenesis (TD) varies by ethnicity.

METHODS

This case-control study included all patients with CH due to TD (a condition of unknown origin) or to dyshormonogenesis (DH, of known autosomal recessive transmission) between 1987 and 2009. Etiology was established by (99m)Tc scintigraphy. The parents self-assessed their ethnicity, which we grouped in Caucasian, Hispanic, black, Asian, and Maghreb/Middle East. We compared ethnicity between the 190 patients with TD (147 ectopies, 40 athyreoses, and 3 orthotopic hypoplasias) and the 44 patients with DH. Ethnicity was also compared to the reference population of the city of Montreal. Prevalence odds ratios (POR) were calculated and compared by the bilateral Fisher's exact test.

RESULTS

The ethnic composition of the DH group was similar to that of the reference population. In blacks, TD prevalence of 1 in 190 (0.5%) was low compared to that of DH (4 in 44; 9.1%; POR 0.06; 95% confidence interval: 0.001-0.56; p = 0.005). In contrast, Caucasians showed an increased TD prevalence of 166 in 190 (87.3%) compared to that of DH (30 in 44; 68.2%; POR 3.21; 95% confidence interval: 1.37-7.34; p = 0.0052). No statistically significant differences were observed between other ethnic groups.

CONCLUSION

TD is less prevalent in blacks and more prevalent in Caucasians. Blacks being more genetically diverse, this is an argument for an oligogenic inheritance of susceptibility to TD.

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.

Trends in incidence rates of congenital hypothyroidism related to select demographic factors: data from the United States, California, Massachusetts, New York, and Texas

Primary congenital hypothyroidism (CH) is a common and preventable cause of intellectual disability. The incidence rate of CH has been reported to be increasing in the United States, but the factors behind the observed rate increase are not known. We summarize here the data presented at a workshop on CH, at which factors potentially related to the CH-incidence-rate increase (namely, race, ethnicity, sex, and birth outcomes) were evaluated. Data sources for the analyses included a national data set of newborn-screening results and state-specific data from newborn-screening programs in California, Massachusetts, New York, and Texas. The incidence rate of CH increased in the United States by 3% per year; however, an increase did not occur in all states, at a constant rate, or even at the same rate. Analysis of US data (1991-2000) showed a CH-incidence-rate increase only among white newborns. More recently, in California (2000-2007), the rate was constant in non-Hispanic newborns, but it increased among Hispanic newborns. In the national data, the CH-incidence rate increased similarly among boys and girls, whereas in Texas (1992-2006), the rate among boys increased significantly more than among girls and varied according to race and ethnicity. In Massachusetts (1995-2007), low birth weight newborns or newborns who had a delayed rise in thyrotropin concentration accounted for the majority of the recent rate increase. Race, ethnicity, sex, and pregnancy outcomes have affected the observed increasing incidence rate of CH, although there have been some inconsistencies and regional differences. The association with preterm birth or low birth weight could reflect the misclassification of some cases of transient hypothyroxinemia as true CH. Future studies of risk factors should focus on correct initial identification and reporting of demographic characteristics and pregnancy outcomes for cases of CH. In addition, long-term follow-up data of presumed cases of CH should be ascertained to differentiate true cases of CH from cases of transient hypothyroidism.

Future research directions to identify causes of the increasing incidence rate of congenital hypothyroidism in the United States

A workshop to evaluate the reported increasing trend in the incidence rate of primary congenital hypothyroidism (CH) identified by newborn screening was held February 27 and 28, 2008, in Atlanta, Georgia, and was sponsored by the Centers for Disease Control and Prevention, the Health Resources and Services Administration, and the National Newborn Screening and Genetics Resource Center. Through a series of presentations and discussions, this group of experts considered a variety of factors that could be contributing to the perceived increasing trend of the CH-incidence rate, the gaps in knowledge that need to be overcome to identify the causes of the observed trend, and possible future research activities that might resolve the uncertainties surrounding the increasing incidence rate of CH in the United States. On the basis of these discussions, workshop participants concluded that the initial focus of future efforts should be to determine if the increasing CH-incidence rate persists once there is standardization of the diagnostic criteria for the classification of CH versus transient hypothyroidism. In discussions, workshop participants suggested that if the increasing incidence rate of CH could not be explained by definitional issues, then future research could focus on the identification and evaluation of risk factors for CH that might be changing among the US population and, thus, contributing to the observed increasing incidence rate of CH.

Discontinuation of thyroid hormone treatment among children in the United States with congenital hypothyroidism: findings from health insurance claims data

BACKGROUND

Thyroid hormone treatment in children with congenital hypothyroidism can prevent intellectual disability. Guidelines recommend that children diagnosed with congenital hypothyroidism through newborn screening remain on treatment to at least 3 years of age, after which a trial off therapy can determine which children have transient hypothyroidism. The purpose of this study was to describe the rate at which children with congenital hypothyroidism in the United States discontinue thyroid hormone treatment in early childhood.

METHODS

Retrospective analysis of the 2002-2006 MarketScan(R) Commercial Claims and Encounters research databases and the 2001-2005 MarketScan Multi-State Medicaid databases. Children were classified as having congenital hypothyroidism based on billing codes and having filled a prescription for thyroid hormone treatment. Kaplan-Meier curve analysis was used to determine discontinuation rates.

RESULTS

There were a total of 412 Medicaid-enrolled children and 292 privately-insured children with presumed congenital hypothyroidism included in this study. The overall birth prevalence of congenital hypothyroidism across both datasets was about 1 per 2,300. By 36 months, the percentage who had discontinued thyroid replacement treatment was 38% (95% Confidence Interval: 32%-44%). Medicaid-enrolled children had a more rapid decline in the first 24 months of treatment compared to those with private insurance (P = 0.02).

CONCLUSIONS

More than one-third of children treated for congenital hypothyroidism discontinued treatment within 36 months, which is inconsistent with current guidelines. It is not known how many of these children required continued treatment or experience adverse effects from discontinuation. These findings emphasize the critical need for follow-up systems to monitor the outcome of newborn screening.