Cynthia F. Hinton

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.

The Impact of Transient Hypothyroidism on the Increasing Rate of Congenital Hypothyroidism in the United States

The reported incidence rate of primary congenital hypothyroidism (CH) has been increasing in the United States over the past 2 decades. We have considered the possibility that the inclusion of cases of transient hypothyroidism has inflated the reported incidence rate of CH. Assessing the effects of cases of transient hypothyroidism on the incidence rate is problematic, because the definitions, diagnostic criteria, and differentiation from transient hyperthyrotropinemia vary widely among state newborn screening programs. Among the 4 etiologies for transient hypothyroidism (maternal thyrotropin receptor–blocking antibodies, exposure to maternal antithyroid medications, iodine deficiency, and iodine excess), there is little evidence of increases in the incidence rate from thyrotropin receptor–blocking antibodies. Exposure to antithyroid drugs could contribute significantly to the incidence rate of transient CH, given the high estimated incidence of active maternal hyperthyroidism. Iodine deficiency or excess in the United States seems unlikely to have contributed significantly to the incidence rate of CH, because the secular trend toward lower iodine intake among women of reproductive age in the 1980s and 1990s seems to have plateaued, and perinatal iodine exposure has presumably declined as a result of recommendations to discontinue using iodine-containing disinfectants. Although the female-to-male sex ratio among newborns with thyroid agenesis or dysgenesis (the most common causes of CH) is typically 2:1, analysis of the sex ratio of newborns diagnosed with presumed CH in the United States suggests that a substantial proportion might have transient hypothyroidism or hyperthyrotropinemia, because the sex ratio has been well below the expected 2:1 ratio. Combined ultrasonography and 123I scintigraphy of the thyroid gland are effective tools for identifying cases of thyroid agenesis and dysgenesis and can help to differentiate cases of transient hypothyroidism from true CH. Imaging is also a vital component in evaluating children who, at 3 years of age, undergo a trial of discontinuation of levothyroxine treatment to test for persistence of hypothyroidism. Ultimately, thyroid gland imaging, in conjunction with long-term follow-up studies that appropriately assess and report whether there was permanence of hypothyroidism, will be necessary to address the true incidence rate of CH and any contribution to the observed rate by transient cases of hypothyroidism or hyperthyrotropinemia.

Results From the New Jersey Statewide Critical Congenital Heart Defects Screening Program

BACKGROUND AND OBJECTIVE: New Jersey was the first state to implement legislatively mandated newborn pulse oximetry screening (POxS) in all licensed birthing facilities to detect critical congenital heart defects (CCHDs). The objective of this report was to evaluate implementation of New Jersey’s statewide POxS mandate. METHODS: A 2-pronged approach was used to collect data on infants screened in all New Jersey birthing facilities from August 31, 2011, through May 31, 2012. Aggregate screening results were submitted by each birthing facility. Data on failed screens and clinical characteristics of those newborns were reported to the New Jersey Birth Defects Registry (NJBDR). Three indicators were used to distinguish the added value of mandated POxS from standard clinical care: prenatal congenital heart defect diagnosis, cardiology consultation or echocardiogram indicated or performed before PoxS, or clinical findings at the time of POxS warranting a pulse oximetry measurement. RESULTS: Of 75 324 live births in licensed New Jersey birthing facilities, 73 320 were eligible for screening, of which 99% were screened. Forty-nine infants with failed POxS were reported to the NJBDR, 30 of whom had diagnostic evaluations solely attributable to the mandated screening. Three of the 30 infants had previously unsuspected CCHDs and 17 had other diagnoses or non-CCHD echocardiogram findings. CONCLUSIONS: In the first 9 months after implementation, New Jersey achieved a high statewide screening rate and established surveillance mechanisms to evaluate the unique contribution of POxS. The screening mandate identified 3 infants with previously unsuspected CCHDs that otherwise might have resulted in significant morbidity and mortality and also identified other significant secondary targets such as sepsis and pneumonia.

Maternal and Neonatal Vitamin B12 Deficiency Detected through Expanded Newborn Screening—United States, 2003–2007

The incidence of neonatal vitamin B12 (cobalamin) deficiency because of maternal deficiency was determined by surveying state newborn screening programs. Thirty-two infants with nutritional vitamin B12 deficiency were identified (0.88/100,000 newborns). Pregnant women should be assessed for their risk of inadequate intake/malabsorption of vitamin B12.

Birth Prevalence Rates of Newborn Screening Disorders in Relation to Screening Practices in the United States

OBJECTIVE To examine the associations between the first-tier-screening laboratory methods and criteria and the birth prevalence of congenital adrenal hyperplasia (CAH), phenylketonuria (PKU), and the sickle hemoglobinopathies occurring in the United States between 1991 and 2000. STUDY DESIGN By using validated data from the National Newborn Screening and Genetics Resource Center, we fit Poisson regression models with laboratory methods and criteria used in every year for each state for each disorder. We also examined whether there was an overall change in birth prevalence over the decade and whether there was an effect resulting from obligatory second screenings. RESULTS There were no associations among any of the factors and the birth prevalence of PKU in this decade. Use of the enzyme-linked immunosorbent assay was more likely than any other laboratory method to identify cases of CAH (OR 1.16; 95% CI 1.04-1.30), but no other factors were associated with this disorder. None of the factors examined were associated with the birth prevalence rates of any of the sickle hemoglobinopathies. CONCLUSION There were no substantial changes in the birth prevalence rates of PKU, CAH, or the sickle hemoglobinopathies over the study period despite rapid changes in technology.

Developing a public health-tracking system for follow-up of newborn screening metabolic conditions: a four-state pilot project structure and initial findings

Purpose:The aim of this study was to describe the methods, cases, and initial results of a pilot project using existing public health data collection programs (birth defect surveillance or newborn screening) to conduct long-term follow-up of children with metabolic disorders.Methods:California, Iowa, New York, and Utah expanded birth defect surveillance or newborn screening programs to collect long-term follow-up data on 19 metabolic disorders. Data elements to monitor health status and services delivered were identified, and record abstraction and data linkages were conducted. Children were followed up through to the age of 3 years.Results:A total of 261 metabolic cases were diagnosed in 1,343,696 live births (19.4 cases/100,000; 95% confidence interval = 17.1–21.8). Four deaths were identified. Children with fatty acid oxidation disorders had a higher percentage of health service encounters compared with children with other disorders of at least one health service encounter (hospitalization, emergency room, metabolic clinic, genetic service provider, or social worker) except for hospitalizations; children with organic acid disorders had a higher percentage of at least one hospitalization during their third year of life than children with other disorders.Conclusion:Existing public health data programs can be leveraged to conduct population-based newborn screening long-term follow-up. This approach is flexible according to state needs and resources. These data will enable the states in assessing health burden, assuring access to services, and supporting policy development.Genet Med 16 6, 484–490.

Ethical implications and practical considerations of ethnically targeted screening for genetic disorders: the case of hemoglobinopathy screening

The prevalence of hemoglobinopathies differs among populations due to genetic differences and due to the protective effects of the heterozygote (carrier) state against malaria. Because of the difference in genetic distribution, public health programs have weighed the ethical versus practical implications of ethnically targeted versus universal newborn, and where applicable, prenatal screening. We examine newborn and prenatal screening for hemoglobinopathies in relation to the use of ‘race’ and ethnicity to assess risk for genetic conditions. First, categories of race/ethnicity are social constructs, therefore, observed or self-identified broad racial/ethnic categories are correlated but not necessarily reliable indicators of geographic ancestry or genetic risk. Second, targeting based on ethnicity poses serious issues of logistics and equity for public health programs and clinical services. In the past, newborn screening for hemoglobinopathies in the United States and United Kingdom was often selective, targeted to women of certain ethnic groups or areas with large concentrations of ethnic minority groups. Presently, newborn screening for hemoglobinopathies is universal in both countries and programs emphasize that individuals of all ethnic backgrounds are at risk for carrying a hemoglobin genetic variant. Reported race/ethnicity is still used as a criterion for offering prenatal carrier testing in the United States, where it is not a public health responsibility. In the United Kingdom, prenatal screening under the National Health Service is universal in high-prevalence areas and in low-prevalence areas is targeted based on reported ancestry. The continued use of targeted prenatal screening in both countries reflects the different purposes and modes of laboratory testing in newborn and prenatal screening. The ethical imperative to identify as many affected infants with life-threatening conditions as possible in newborn screening programs is not applicable to prenatal carrier testing. Because newborn screening dried blood spot specimens are tested for multiple disorders, targeted screening poses serious logistical challenges which is not the case in prenatal screening.

CDC Grand Rounds: Addressing Preparedness Challenges for Children in Public Health Emergencies.

Recent public health emergencies including Hurricane Katrina (2005), the influenza H1N1 pandemic (2009), and the Ebola virus disease outbreak in West Africa (2014–2015) have demonstrated the importance of multiple-level emergency planning and response. An effective response requires integrating coordinated contributions from community-based health care providers, regional health care coalitions, state and local health departments, and federal agency initiatives. This is especially important when planning for the needs of children, who make up 23% of the U.S. population (1) and have unique needs that require unique planning strategies.

Congenital adrenal hyperplasia cases identified by newborn screening in one- and two-screen states ☆

There is no clear consensus among state newborn screening programs on whether routine second screening of newborns identifies clinically relevant cases of congenital adrenal hyperplasia. This retrospective study evaluated laboratory practices, along with biochemical and medical characteristics of congenital adrenal hyperplasia (CAH) cases (1) detected on the first newborn screen in one-screen compared to two-screen states, and (2) detected on the first versus the second screen in the two-screen states, to determine the effectiveness of a second screen. A total of 374 confirmed cases of CAH from 2 one-screen states and 5 two-screen states were included in this study. Demographic data and diagnostic information on each reported case were collected and analyzed. Additionally, laboratory data, including screening methodologies and algorithms, were evaluated. The one-screen states reported 99 cases of CAH out of 1,740,586 (1 in 17,500) newborns screened: 88 (89%) identified on the first screen and 5 (5%) identified on the targeted second screen. The two-screen states reported 275 cases of CAH out of 2,629,627 (1 in 9500) newborns screened: 165 (60%) identified on the first screen and 99 (36%) identified on the second screen. Using a multivariate model, the only significant predictor of whether a case was identified on the first or the second screen in the two-screen states was the type of CAH. Compared with classical salt-wasting CAH, classical simple virilizing and non-classical CAH cases were less likely to be detected on the first versus the second screen. The routine second newborn screen is important for identifying children with CAH, particularly simple virilizing and non-classical forms, which might otherwise not be captured through a single screen.

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.