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Epidemiologic studies of birth defects often conduct separate analyses for cases that have isolated defects (e.g., spina bifida only) and cases that have multiple defects (e.g., spina bifida and a congenital heart defect). However, in some instances, cases with additional defects (e.g., spina bifida and clubfoot) may be more appropriately considered as isolated because the co-occurring defect (clubfoot) is believed to be developmentally related to the defect of interest. Determining which combinations should be considered isolated can be challenging and potentially resource intensive for registries. Thus, we developed automated classification procedures for differentiating between isolated versus multiple defects, while accounting for developmentally related defects, and applied the approach to data from the Texas Birth Defects Registry (1999-2018 deliveries). Among 235,544 nonsyndromic cases in Texas, 89% of cases were classified as having isolated defects, with proportions ranging from 25% to 92% across 43 specific defects analyzed. A large proportion of isolated cases with spina bifida (44%), lower limb reduction defects (44%), and holoprosencephaly (32%) had developmentally related defects. Overall, our findings strongly support the need to account for isolated versus multiple defects in risk factor association analyses and to account for developmentally related defects when doing so, which has implications for interpreting prior studies., (© 2024 Wiley Periodicals LLC.)

Introduction: Traditional strategies for grouping congenital heart defects (CHDs) using birth defect registry data do not adequately address differences in expected clinical consequences between different combinations of CHDs. We report a lesion-specific classification system for birth defect registry-based outcome studies., Methods: For Core Cardiac Lesion Outcome Classifications (C-CLOC) groups, common CHDs expected to have reasonable clinical homogeneity were defined. Criteria based on combinations of Centers for Disease and Control-modified British Pediatric Association (BPA) codes were defined for each C-CLOC group. To demonstrate proof of concept and retention of reasonable case counts within C-CLOC groups, Texas Birth Defect Registry data (1999-2017 deliveries) were used to compare case counts and neonatal mortality between traditional vs. C-CLOC classification approaches., Results: C-CLOC defined 59 CHD groups among 62,262 infants with CHDs. Classifying cases into the single, mutually exclusive C-CLOC group reflecting the highest complexity CHD present reduced case counts among lower complexity lesions (e.g., 86.5% of cases with a common atrium BPA code were reclassified to a higher complexity group for a co-occurring CHD). As expected, C-CLOC groups had retained larger sample sizes (i.e., representing presumably better-powered analytic groups) compared to cases with only one CHD code and no occurring CHDs., Discussion: This new CHD classification system for investigators using birth defect registry data, C-CLOC, is expected to balance clinical outcome homogeneity in analytic groups while maintaining sufficiently large case counts within categories, thus improving power for CHD-specific outcome association comparisons. Future outcome studies utilizing C-CLOC-based classifications are planned., (© 2024 Wiley Periodicals LLC.)

Background: Penoscrotal transposition (PST) is an uncommon urogenital malformation in which the penis is mal-positioned to be inferior to the scrotum. The purpose of this study was to explore PST risk by maternal characteristics and to describe co-occurring congenital abnormalities in the Texas Birth Defects Registry (TBDR)., Methods: We conducted a population-based descriptive study examining occurrence of PST in the TBDR between 1999 and 2019. The primary outcome variable was PST diagnosis during infancy. Descriptive variables included maternal age, education, and race/ethnicity. Prevalence ratios (PRs) were calculated within each maternal variable category using Poisson regression. Counts and percentages of cases with select co-occurring congenital abnormalities were also calculated., Results: Overall, 251 infants had PST, providing a prevalence of 0.61/10,000 live male births (95% CI: 0.53-0.68). PST prevalence was significantly lower among infants of mothers who had lower educational attainment (high school), who were younger (<25 vs. 25-34), and who were Hispanic (vs. non-Hispanic White) and was significantly higher among older mothers (35+ vs. 25-39). Hypospadias was the most common co-occurring genitourinary anomaly, affecting close to 70% of cases., Conclusions: To our knowledge, this is the first investigation exploring the prevalence of PST in a population-based birth defects registry. Our findings help to understand the risk for PST among select maternal demographic characteristics and may assist in generating hypotheses about the underlying etiology of this condition for future work., (© 2023 Wiley Periodicals LLC.)

Background: Few studies of congenital anomalies provide prevalence estimates stratified by maternal race/ethnicity. We sought to determine whether the prevalence of a broad spectrum of anomalies varies among offspring of women from different race/ethnic groups., Methods: We obtained information on cases with anomalies from the population-based Texas Birth Defects Registry, and denominator data on livebirths among Texas residents during 1999-2018 from the Texas Center for Health Statistics. We estimated the prevalence ratio (PR) and 95% confidence interval (CI) of N = 145 anomalies among offspring of Hispanic and non-Hispanic Black relative to non-Hispanic White women using Poisson regression, adjusting for maternal age, education, body mass index, and previous livebirths. We performed a two-stage analysis with a Bonferroni-adjusted p < 1.7 × 10 -4 in the initial screening phase to identify anomalies with statistically significant variation., Results: There were 7,698,768 livebirths and 1,187,385 anomalies diagnosed in 368,393 cases. The prevalence of any monitored congenital anomaly was similar among offspring of non-Hispanic White (referent), non-Hispanic Black (PR 0.98, CI 0.96-1.00), and Hispanic (PR 0.95, CI 0.93-0.96) women. We observed statistically significant racial/ethnic variation for 42 anomalies. Marked differences were observed when comparing offspring of non-Hispanic Black to non-Hispanic White women with respect to polydactyly (PR 4.38, CI 4.07-4.72), pyloric stenosis (PR 0.34, CI 0.29-0.40), and aortic valve atresia/stenosis (PR 0.51, CI 0.36-0.72)., Conclusions: Birth prevalence of many major congenital anomalies varies by maternal race and ethnicity. While the reasons for these differences are likely multifactorial, a thorough understanding of racial and ethnic disparities is useful to stimulate etiologic research., (© 2023 Wiley Periodicals LLC.)

Background: Building on findings that linked higher levels of sunspot (SS) activity with a range of health and adverse birth outcomes, we sought to understand how SS activity over a 17-year time period may be correlated with the occurrence of birth defects., Methods: Data from the Texas Birth Defects Registry, vital events from the Texas Center for Health Statistics, and mean monthly numbers of sunspots from the National Oceanic and Atmospheric Administration were utilized. Poisson regression was used to calculate crude/adjusted prevalence ratios (cPRs/aPRs) and 95% confidence intervals for three quartiles (Q) of increasing SS activity (compared to a referent of low activity) and 44 birth defects (31 non-cardiac; 13 cardiac) with estimated dates of conception from 1998 to 2016., Results: We found moderately protective aPRs (range: 0.60-0.89) in a little over half of the case groups examined in our quartiles of higher SS activity (19 non-cardiac; 6 cardiac), after adjusting for maternal age, race/ethnicity, and education. Particularly protective aPRs in the highest SS quartiles (Q3-4) were noted for: anophthalmia, cataract, gastroschisis, trisomy 18, ventricular septal defects, atrial septal defects, and pulmonary valve atresia or stenosis. Conversely, modestly elevated aPRs were noted for two defect groups (agenesis, aplasia, and hypoplasia of the lung and microcephaly [Q2-3]). Following an additional adjustment of year of conception, results remained similar although many of the estimates were attenuated., Conclusion: The seemingly protective associations between increasing SS activity may be an artifact of increasing spontaneous abortions that occur following conception during these periods of heightened SS activity., (© 2023 Wiley Periodicals LLC.)

Many infants with anotia or microtia (A/M) have co-occurring birth defects, although few receive syndromic diagnoses in the perinatal period. Evaluation of co-occurring birth defects in children with A/M could identify patterns indicative of undiagnosed/unrecognized syndromes. We obtained information on co-occurring birth defects among infants with A/M for delivery years 1999-2014 from the Texas Birth Defects Registry. We calculated observed-to-expected ratios (OER) to identify birth defect combinations that occurred more often than expected by chance. We excluded children diagnosed with genetic or chromosomal syndromes from analyses. Birth defects and syndromes/associations diagnosed ≤1 year of age were considered. We identified 1310 infants with non-syndromic A/M, of whom 38% (N = 492) were diagnosed with co-occurring major defects. Top combinations included: hydrocephalus, ventricular septal defect, and spinal anomalies (OER 58.4); microphthalmia and anomalies of the aorta (OER 55.4); and cleft lip with or without cleft palate and rib or sternum anomalies (OER 32.8). Some combinations observed in our study may represent undiagnosed/atypical presentations of known A/M associations or syndromes, or novel syndromes yet to be described in the literature. Careful evaluation of infants with multiple birth defects including A/M is warranted to identify individuals with potential genetic or chromosomal syndromes., (© 2022 Wiley Periodicals LLC.)

Background: Few risk factors have been identified for nonsyndromic anotia/microtia (A/M)., Methods: We obtained data on cases and a reference population of all livebirths in Texas for 1999-2014 from the Texas Birth Defects Registry (TBDR) and Texas vital records. We estimated prevalence ratios (PRs) and 95% confidence intervals (CIs) for A/M (any, isolated, nonisolated, unilateral, and bilateral) using Poisson regression. We evaluated trends in prevalence rates using Joinpoint regression., Results: We identified 1,322 cases, of whom 982 (74.3%) had isolated and 1,175 (88.9%) had unilateral A/M. Prevalence was increased among males (PR: 1.3, 95% CI: 1.2-1.4), offspring of women with less than high school education (PR: 1.3, 95% CI: 1.1-1.5), diabetes (PR: 2.0, 95% CI: 1.6-2.4), or age 30-39 versus 20-29 years (PR: 1.2, 95% CI: 1.0-1.3). The prevalence was decreased among offspring of non-Hispanic Black versus White women (PR: 0.6, 95% CI: 0.4-0.8) but increased among offspring of Hispanic women (PR: 2.9, 95% CI: 2.5-3.4) and non-Hispanic women of other races (PR: 1.7, 95% CI: 1.3-2.3). We observed similar results among cases with isolated and unilateral A/M. Sex disparities were not evident for nonisolated or bilateral phenotypes, nor did birth prevalence differ between offspring of non-Hispanic Black and non-Hispanic White women. Maternal diabetes was more strongly associated with nonisolated (PR: 4.5, 95% CI: 3.2-6.4) and bilateral A/M (PR: 5.0, 95% CI: 3.3-7.7). Crude prevalence rates increased throughout the study period (annual percent change: 1.82)., Conclusion: We identified differences in the prevalence of nonsyndromic A/M by maternal race/ethnicity, education, and age, which may be indicators of unidentified social/environmental risk factors., (© 2022 Wiley Periodicals LLC.)

Background: There is considerable variability in the prevalence of birth defects among racial/ethnic groups. This study estimated birth defect prevalence among the less studied non-Hispanic (NH) Asian/Pacific Islander (PI) and American Indian/Alaska Native (AI/AN) populations in Texas relative to NH Whites., Methods: Data were obtained from the Texas Birth Defect Registry from 1999 to 2015 for deliveries to Texas-resident women who were NH White, NH Asian/PI, or AI/AN. This covers a live birth population of 2.6 million. Prevalence ratios and 95% confidence intervals (95% CIs) were calculated for NH Asian/PIs and AI/ANs (relative to NH Whites) for 44 birth defects using Poisson regression adjusting for maternal age., Results: After adjustment there were 33 statistically significant prevalence ratios (aPRs). Among NH Asian/PIs, 23 defects had a lower aPR (0.38-0.86) and three defects had a higher aPR (1.19-2.50). AI/ANs had one defect with a significantly lower aPR (0.64) and six with a higher aPR (1.36-4.63)., Conclusions: Non-Hispanic Asian/PIs generally have a lower prevalence ratio for many birth defects while AI/ANs have a higher prevalence ratio compared to NH Whites. These findings update the limited literature on this topic and warrant additional research to identify the true associations across a range of birth defects among these understudied racial/ethnic groups., (© 2019 Wiley Periodicals, Inc.)