Russel Rickard

Updated National Birth Prevalence estimates for selected birth defects in the United States, 2004-2006.

BACKGROUND The National Birth Defects Prevention Network collects state-specific birth defects surveillance data for annual publication of prevalence estimates and collaborative research projects. In 2006, data for 21 birth defects from 1999 through 2001 were presented as national birth prevalence estimates. The purpose of this report was to update these estimates using data from 2004 through 2006. METHODS Population-based data from 11 active case-finding programs, 6 passive case-finding programs with case confirmation, and 7 passive programs without case confirmation were used in this analysis. Pooled birth prevalence estimates for 21 birth defects, stratified by case ascertainment approach, were calculated. National prevalence estimates, adjusted for maternal race/ethnicity and maternal age (trisomy 13, trisomy 18, and Down syndrome only) were determined using data from 14 programs. The impact of pregnancy outcomes on prevalence estimates was also assessed for five specific defects. RESULTS National birth defects prevalence estimates ranged from 0.72 per 10,000 live births for common truncus to 14.47 per 10,000 live births for Down syndrome. Stratification by type of surveillance system showed that active programs had a higher prevalence of anencephaly, anophthalmia/microphthalmia, cleft lip with or without cleft palate, reduction defect of upper limbs, and trisomy 18. The birth prevalence of anencephaly, trisomy 13, and trisomy 18 also varied substantially with inclusion of elective terminations. CONCLUSION Accurate and timely national estimates of the prevalence of birth defects are needed for monitoring trends, assessing prevention efforts, determining service planning, and understanding the burden of disease due to birth defects in the United States.

Prevalence and correlates of gastroschisis in 15 states, 1995 to 2005.

OBJECTIVE: To identify trends in the prevalence and epidemiologic correlates of gastroschisis using a large population-based sample with cases identified by the National Birth Defects Prevention Network over the course of an 11-year period. METHODS: This study examined 4,713 cases of gastroschisis occurring in 15 states during 1995–2005, using public use natality data sets for denominators. Multivariable Poisson regression was used to identify statistically significant risk factors, and Joinpoint regression analyses were conducted to assess temporal trends in gastroschisis prevalence by maternal age and race and ethnicity. RESULTS: Results show an increasing temporal trend for gastroschisis (from 2.32 per 10,000 to 4.42 per 10,000 live births). Increasing prevalence of gastroschisis has occurred primarily among younger mothers (11.45 per 10,000 live births among mothers younger than age 20 years compared with 5.35 per 10,000 among women aged 20 to 24 years). In the multivariable analysis, using non-Hispanic whites as the referent group, non-Hispanic black women had the lowest risk of having a gastroschisis-affected pregnancy (prevalence ratio 0.42, 95% confidence interval [CI] 0.37–0.48), followed by Hispanics (prevalence ratio 0.86, 95% CI 0.81–0.92). Gastroschisis prevalence did not differ by newborn sex. CONCLUSIONS: Our findings demonstrate that the prevalence of gastroschisis has been increasing since 1995 among 15 states in the United States, and that higher rates of gastroschisis are associated with non-Hispanic white maternal race and ethnicity, and maternal age younger than 25 years (particularly younger than 20 years of age). LEVEL OF EVIDENCE: III

Multistate study of the epidemiology of clubfoot.

BACKGROUND Although clubfoot is a common birth defect, with a prevalence of approximately 1 per 1000 livebirths, the etiology of clubfoot remains largely unknown. Studies of the prevalence and risk factors for clubfoot in the United States have previously been limited to specific states. The purpose of this study was to pool data from several birth defects surveillance programs to better estimate the prevalence of clubfoot and investigate its risk factors. METHODS The 10 population-based birth defects surveillance programs that participated in this study ascertained 6139 cases of clubfoot from 2001 through 2005. A random sample of 10 controls per case, matched on year and state of birth, was selected from birth certificates. Data on infant and maternal risk factors were collected from birth certificates. Prevalence was calculated by pooling the state-specific data. Conditional logistic regression was used to investigate the association between risk factors and clubfoot. RESULTS The overall prevalence of clubfoot was 1.29 per 1000 livebirths; 1.38 among non-Hispanic whites, 1.30 among Hispanics, and 1.14 among non-Hispanic blacks or African Americans. Maternal age, parity, education, and marital status were significantly associated with clubfoot. Maternal smoking and diabetes also showed significant associations. Several of these observed associations were consistent between surveillance programs. CONCLUSIONS We estimated the prevalence of clubfoot using data from several birth defects programs, representing one-quarter of all births in the United States. Our findings underline the importance of birth defects surveillance programs and their utility in monitoring population-based prevalence and investigating risk factors.

Selected birth defects data from population-based birth defects surveillance programs in the United States, 2006 to 2010: Featuring trisomy conditions

The annual National Birth Defects Prevention Network (NBDPN) Congenital Malformations Surveillance Report includes state-level data on major birth defects (i.e., conditions present at birth that cause adverse structural changes in one or more parts of the body) and a directory of population-based birth defects surveillance systems in the United States. Beginning in 2012, these annually updated data and directory information are available in an electronic format accompanied by a data brief. This year’s report includes data from 41 population-based birth defects surveillance programs and a data brief highlighting the more common trisomy conditions (i.e., disorders characterized by an additional chromosome): trisomy 21 (commonly referred to as Down syndrome), trisomy 18, and trisomy 13. State-Specific Data Collection and Presentation for Selected Birth Defects Data collection The NBDPN Data Committee, in collaboration with the Centers for Disease Control and Prevention (CDC), invited population-based birth defects surveillance programs in the United States to submit data on major birth defects affecting central nervous, eye, ear, cardiovascular, orofacial, gastrointestinal, genitourinary, and musculoskeletal systems, as well as trisomies, amniotic bands, and fetal alcohol syndrome. Table 1 lists these 47 conditions and their diagnostic codes (International Classification of Diseases, 9th Revision, Clinical Modification [ICD-9-CM]; and Centers for Disease Control and Prevention/British Pediatric Association Classification of Diseases [CDC/BPA]). Table 1 ICD-9-CM and CDC/BPA Codes for 47 Birth Defects Reported in the NBDPN Annual Report Participating state birth defects programs provided counts of all cases of the birth defects listed in Table 1 as well as counts of live births and male live births in their catchment areas for births occurring from January 1, 2006 through December 31, 2010. The cases for all defects were reported by maternal census race/ethnic categories: White non-Hispanic, Black/African-American non-Hispanic, Hispanic, Asian/Pacific Islander non-Hispanic, American Indian/Alaska Native non-Hispanic. Additionally, trisomy cases were provided by six categories of maternal age at delivery: less than 20 years, 20 to 24 years, 25 to 29 years, 30 to 34 years, 35 to 39 years, and 40+ years.

The Association Between Race/Ethnicity and Major Birth Defects in the United States, 1999–2007

OBJECTIVES We investigated the relationship between race/ethnicity and 27 major birth defects. METHODS We pooled data from 12 population-based birth defects surveillance systems in the United States that included 13.5 million live births (1 of 3 of US births) from 1999 to 2007. Using Poisson regression, we calculated prevalence estimates for each birth defect and 13 racial/ethnic groupings, along with crude and adjusted prevalence ratios (aPRs). Non-Hispanic Whites served as the referent group. RESULTS American Indians/Alaska Natives had a significantly higher and 50% or greater prevalence for 7 conditions (aPR = 3.97; 95% confidence interval [CI] = 2.89, 5.44 for anotia or microtia); aPRs of 1.5 to 2.1 for cleft lip, trisomy 18, and encephalocele, and lower, upper, and any limb deficiency). Cubans and Asians, especially Chinese and Asian Indians, had either significantly lower or similar prevalences of these defects compared with non-Hispanic Whites, with the exception of anotia or microtia among Chinese (aPR = 2.08; 95% CI = 1.30, 3.33) and Filipinos (aPR = 1.90; 95% CI = 1.10, 3.30) and tetralogy of Fallot among Vietnamese (aPR = 1.60; 95% CI = 1.11, 2.32). CONCLUSIONS This is the largest population-based study to our knowledge to systematically examine the prevalence of a range of major birth defects across many racial/ethnic groups, including Asian and Hispanic subgroups. The relatively high prevalence of birth defects in American Indians/Alaska Natives warrants further attention.

Birth defects data from population-based birth defects surveillance programs in the United States, 2007 to 2011: Highlighting orofacial clefts

© 2014 The Authors Birth Defects Research Part A: Clinical and Molecular Teratology Published by Wiley Periodicals, Inc.

Prevalence, Correlates, and Outcomes of Omphalocele in the United States, 1995-2005.

OBJECTIVE: To examine the trends in the prevalence, epidemiologic correlates, and 1-year survival of omphalocele using 1995–2005 data from the National Birth Defects Prevention Network in the United States. METHODS: We examined 2,308 cases of omphalocele over 11 years from 12 state population-based birth defects registries. We used Poisson regression to estimate prevalence and risk factors for omphalocele and Kaplan-Meier survival curves and Cox proportional hazards regression to estimate survival patterns and hazard ratios, respectively, to examine isolated compared with nonisolated cases. RESULTS: Birth prevalence of omphalocele was 1.92 per 10,000 live births with no consistent trend over time. Neonates with omphalocele were more likely to be male (prevalence ratio 1.22, 95% confidence interval [CI] 1.12–1.34), born to mothers 35 years of age or older (prevalence ratio 1.77, 95% CI 1.54–2.04) and younger than 20 years (prevalence ratio 1.34, 95% CI 1.14–1.56), and of multiple births (prevalence ratio 2.22, 95% CI 1.85–2.66). The highest proportion of neonates with omphalocele had congenital heart defects (32%). The infant mortality rate was 28.7%, with 75% of those occurring in the first 28 days. The best survival was for isolated cases and the worst for neonates with chromosomal defects (hazard ratio 7.75, 95% CI 5.40–11.10) and low-birth-weight neonates (hazard ratio 7.51, 95% CI 5.86–9.63). CONCLUSION: Prevalence of omphalocele has remained constant from 1995 to 2005. Maternal age (younger than 20 years and 35 years or older), multiple gestation, and male sex are important correlates of omphalocele, whereas co-occurrence with chromosomal defects and very low birth weight are consistent determinants of 1-year survival among these neonates. LEVEL OF EVIDENCE: II

Development and implementation of the first national data quality standards for population-based birth defects surveillance programs in the United States

BackgroundPopulation-based birth defects surveillance is a core public health activity in the United States (U.S.); however, the lack of national data quality standards has limited the use of birth defects surveillance data across state programs. Development of national standards will facilitate data aggregation and utilization across birth defects surveillance programs in the U.S.MethodsBased on national standards for other U.S. public health surveillance programs, existing National Birth Defects Prevention Network (NBDPN) guidelines for conducting birth defects surveillance, and information from birth defects surveillance programs regarding their current data quality practices, we developed 11 data quality measures that focused on data completeness (n = 5 measures), timeliness (n = 2), and accuracy (n = 4). For each measure, we established tri-level performance criteria (1 = rudimentary, 2 = essential, 3 = optimal). In January 2014, we sent birth defects surveillance programs in each state, District of Columbia, Puerto Rico, Centers for Disease Control and Prevention (CDC), and the U.S. Department of Defense Birth and Infant Health Registry an invitation to complete a self-administered NBDPN Standards Data Quality Assessment Tool. The completed forms were electronically submitted to the CDC for analyses.ResultsOf 47 eligible population-based surveillance programs, 45 submitted a completed assessment tool. Two of the 45 programs did not meet minimum inclusion criteria and were excluded; thus, the final analysis included information from 43 programs. Average scores for four of the five completeness performance measures were above level 2. Conversely, the average scores for both timeliness measures and three of the four accuracy measures were below level 2. Surveillance programs using an active case-finding approach scored higher than programs using passive case-finding approaches for the completeness and accuracy measures, whereas their average scores were lower for timeliness measures.ConclusionsThis initial, nation-wide assessment of data quality across U.S. population-based birth defects surveillance programs highlights areas for improvement. Using this information to identify strengths and weaknesses, the birth defects surveillance community, working through the NBDPN, can enhance and implement a consistent set of standards that can promote uniformity and enable surveillance programs to work towards improving the potential of these programs.