Trends and patterns of mortality associated with birth defects and genetic diseases in the United States, 1979-1992: an analysis of multiple-cause mortality data

Geographical variation in infant mortality due to congenital heart disease in the USA: a population-based cohort study

BACKGROUND

Little is known about geographical variation in infant mortality due to congenital heart disease (CHD) and the social determinants of health that might mediate such variation. We aimed to examine US county-level estimates of infant mortality due to CHD to understand geographical patterns and factors that might influence variation in mortality.

METHODS

This US population-based cohort study used linked livebirth-infant death cohort files from the US National Center for Health Statistics from Jan 1, 2006, to Dec 31, 2015. All deaths attributable to congenital heart disease in infants in a given year were included. We used hierarchical Bayesian models to estimate rates of infant mortality due to congenital heart disease for all US counties. We mapped model-based estimates to explore geographical patterns. Covariates included infant sex, gestational age, maternal race and ethnicity, percentage of the county population below the poverty level, and proximity of the county to a US News & World Report 2015 top-50 ranked paediatric cardiac centre.

FINDINGS

From 2006 to 2015, 40 847 089 livebirths occurred, of which there were 13 988 infant deaths attributed to congenital heart disease, with an unadjusted infant mortality rate due to CHD of 0·34 per 1000 livebirths (95% CI 0·34-0·35). Kentucky and Mississippi had the greatest proportions of counties with a predicted rate of infant mortality due to CHD above the 95th percentile. All counties in Connecticut, Massachusetts, and Rhode Island had a predicted rate below the fifth percentile. In the model, lower mortality risk correlated with closer proximity to a top-50 ranked paediatric cardiac centre (odds ratio [OR] 0·890, 95% credible interval [CrI] 0·840-0·942), whereas higher mortality risk correlated with higher levels of poverty (OR 1·181, 95% CrI 1·125-1·239).

INTERPRETATION

Substantial geographical variation exists in infant mortality due to CHD in the USA, highlighting the potential importance of bolstering care delivery for infants from economically deprived communities and areas remote from top-performing paediatric cardiac centres.

FUNDING

None.

Measurement, consequences and determinants of time to diagnosis in children with new-onset heart failure: A population-based retrospective study (DIACARD study)

BACKGROUND

Time from first symptoms to diagnosis, called time to diagnosis, is related to prognosis in several diseases. The aim of this study was to assess time to diagnosis in children with new-onset heart failure (HF) and assess its consequences and determinants.

METHODS

A retrospective population-based observational study was conducted between 2007 and 2016 in a French tertiary care center. We included all children under 16 years old with no known heart disease, and HF confirmed by echocardiography. With logistic regression used for outcomes and a Cox proportional-hazards model for determinants, analyses were stratified by HF etiology: congenital heart diseases (CHD) and cardiomyopathies/myocarditis (CM).

RESULTS

A total of 117 children were included (median age [interquartile range (IQR)] 25 days (6-146), 50.4% were male, 60 had CHD and 57 had CM). Overall median (IQR) time to diagnosis was 3.3 days (1.0-21.2). The frequency of 1-year mortality was 17% and 1-year neuromotor sequel 18%. Death at 1 year was associated with low birth weight for all patients (adjusted odds ratio 0.24, 95% confidence interval [CI] 0.08-0.68) and time to diagnosis below the median with CM (0.09, 0.01-0.87) but not time to diagnosis above the median for all patients (0.59, 0.13-2.66). Short time to diagnosis was associated with clinical severity on the first day of symptoms for all patients (adjusted hazard ratio 3.39, 95% CI 2.01-5.72), and young age with CM (0.09, 0.02-0.41).

CONCLUSIONS

In children with new-onset HF presenting in our region, median time to diagnosis was short. Long time to diagnosis was not associated with poor outcome.

US Mortality Attributable to Congenital Heart Disease Across the Lifespan From 1999 Through 2017 Exposes Persistent Racial/Ethnic Disparities

BACKGROUND

Congenital heart disease (CHD) accounts for ≈40% of deaths in US children with birth defects. Previous US data from 1999 to 2006 demonstrated an overall decrease in CHD mortality. Our study aimed to assess current trends in US mortality related to CHD from infancy to adulthood over the past 19 years and determine differences by sex and race/ethnicity.

METHODS

We conducted an analysis of death certificates from 1999 to 2017 to calculate annual CHD mortality by age at death, race/ethnicity, and sex. Population estimates used as denominators in mortality rate calculations for infants were based on National Center for Health Statistics live birth data. Mortality rates in individuals ≥1 year of age used US Census Bureau bridged-race population estimates as denominators. We used joinpoint regression to characterize temporal trends in all-cause mortality, mortality resulting directly attributable to and related to CHD by age, race/ethnicity, and sex.

RESULTS

There were 47.7 million deaths with 1 in 814 deaths attributable to CHD (n=58 599). Although all-cause mortality decreased 16.4% across all ages, mortality resulting from CHD declined 39.4% overall. The mean annual decrease in CHD mortality was 2.6%, with the largest decrease for those >65 years of age. The age-adjusted mortality rate decreased from 1.37 to 0.83 per 100 000. Males had higher mortality attributable to CHD than females throughout the study, although both sexes declined at a similar rate (≈40% overall), with a 3% to 4% annual decrease between 1999 and 2009, followed by a slower annual decrease of 1.4% through 2017. Mortality resulting from CHD significantly declined among all races/ethnicities studied, although disparities in mortality persisted for non-Hispanic Blacks versus non-Hispanic Whites (mean annual decrease 2.3% versus 2.6%, respectively; age-adjusted mortality rate 1.67 to 1.05 versus 1.35 to 0.80 per 100 000, respectively).

CONCLUSIONS

Although overall US mortality attributable to CHD has decreased over the past 19 years, disparities in mortality persist for males in comparison with females and for non-Hispanic Blacks in comparison with non-Hispanic Whites. Determining factors that contribute to these disparities such as access to quality care, timely diagnosis, and maintenance of insurance will be important moving into the next decade.

Congenital left heart obstruction: ethnic variation in incidence and infant survival

OBJECTIVE

To investigate the relationship between ethnicity and health outcomes among fetuses and infants with congenital left heart obstruction (LHO).

DESIGN

A retrospective population-based review was conducted of fetuses and infants with LHO including all terminations, stillbirths and live births from 20 weeks' gestation in New Zealand over a 9-year period. Disease incidence and mortality were analysed by ethnicity and by disease type: hypoplastic left heart syndrome (HLHS), aortic arch obstruction (AAO), and aortic valve and supravalvular anomalies (AVSA).

RESULTS

Critical LHO was diagnosed in 243 fetuses and newborns. There were 125 with HLHS, 112 with AAO and 6 with isolated AVSA. The incidence of LHO was significantly higher among Europeans (0.59 per 1000) compared with Māori (0.31 per 1000; p<0.001) and Pacific peoples (0.27 per 1000; p=0.002). Terminations were uncommon among Māori and Pacific peoples. Total case fatality was, however, lower in Europeans compared with other ethnicities (42% vs 63%; p=0.002) due to a higher surgical intervention rate and better infant survival. The perinatal and infant mortality rate was 82% for HLHS, 15% for AAO and 2% for AVSA.

CONCLUSION

HLHS carries a high perinatal and infant mortality risk. There are ethnic differences in the incidence of and mortality from congenital LHO with differences in mortality rate suggesting inequities may exist in the perinatal management pathway.

Birth Location of Infants with Critical Congenital Heart Disease in California

The American Academy of Pediatrics classifies neonatal intensive care units (NICUs) from level I to IV based on the acuity of care each unit can provide. Birth in a higher level center is associated with lower morbidity and mortality in high-risk populations. Congenital heart disease accounts for 25-50% of infant mortality related to birth defects in the U.S., but recent data are lacking on where infants with critical congenital heart disease (CCHD) are born. We used a linked dataset from the Office of Statewide Health Planning and Development to access ICD-9 diagnosis codes for all infants born in California from 2008 to 2012. We compared infants with CCHD to the general population, identified where infants with CCHD were born based on NICU level of care, and predicted level IV birth among infants with CCHD using logistic regression techniques. From 2008 to 2012, 6325 infants with CCHD were born in California, with 23.7% of infants with CCHD born at a level IV NICU compared to 8.4% of the general population. Level IV birth for infants with CCHD was associated with lower gestational age, higher maternal age and education, the presence of other congenital anomalies, and the diagnosis of a single ventricle lesion. More infants with CCHD are born in a level IV NICU compared to the general population. Future studies are needed to determine if birth in a lower level of care center impacts outcomes for infants with CCHD.

Role of HDLive in Imaging the Fetal Heart

HDLive is a rendering methodology that generates realistic images of the human fetus from sonographic data. The objective of this study is to demonstrate the utility of high-definition live in evaluating fetal heart especially in the first trimester (11-14-week) scan. The normal atrioventricular valve and its abnormalities along with septal defects can be vividly demonstrated with this technique, and eight cases with cardiac defects are illustrated. Its use in the first-trimester evaluation of heart would give a better perspective of the cardiac malformation, which provides the opportunity for counseling options early in pregnancy.

Timing of diagnosis affects mortality in critical congenital heart disease

OBJECTIVE

Screening for critical congenital heart disease (CHD) with prenatal ultrasound or postnatal pulse oximetry has the potential to improve outcome. To guide screening recommendations, this study aimed to identify the proportion and outcome of major CHD diagnosed before (early) or after (late) postnatal discharge prior to the introduction of postnatal oximetry screening.

DESIGN

A retrospective, population-based review of all major CHD in New Zealand from 2006 to 2010. The timing of diagnosis relative to discharge and to intervention in critical and non-critical cases with intention to treat was determined, as was the relationship of diagnostic timing to mortality at 1 year of age.

RESULTS

Late diagnosis occurred in 20% of critical and 51% of non-critical cases. Mortality occurred in 18% of critical vs 8% of non-critical cases. Mortality was lower with an early diagnosis of critical CHD (early diagnosis 16% vs late diagnosis 27%, p=0.04). Isolated critical CHD benefited most from early diagnosis (mortality, early diagnosis 12% vs late diagnosis 29%, p=0.002). Early diagnosis occurred in >90% critical complex CHD and hypoplastic left heart syndrome, 85% d-transposition of the great arteries (d-TGA) and 53% critical left ventricular outflow tract obstruction (LVOTO). Deaths in d-TGA and LVOTO primarily occurred prior to intervention and for d-TGA most often when birth was distant from the cardiac centre.

CONCLUSIONS

Excess mortality occurs following late diagnosis of critical CHD, and for d-TGA even with early diagnosis if intervention is not immediately available. Antenatal detection retains an important role in reducing mortality related to critical CHD.

The Ultrasonic Microsurgical Anatomical Comparative Study of the CHD Fetuses and Their Clinical Significance

The aim of our study was to increase the detection rate of fetal cardiac malformations for congenital heart disease (CHD). The ultrasonic and microanatomical methods were combined to study the CHD cases firstly, which could provide the microsurgical anatomical basis to the prenatal ultrasonic diagnosis which was used in suspected CHD and help the sonographer to improve the quality of fetal cardiac diagnosis. We established the ultrasonic standard section of the 175 complex CHD cases and collected the fetal echocardiography image files. The induced/aborted fetuses were fixed by 4% paraformaldehyde and dissected by the ultrasonic microsurgical anatomy. This research could obtain the fetal cardiac anatomic cross-sectional images which was consistent with the ultrasonic standard section and could clearly show the internal structure of the vascular malformation that optimized the ultrasound examination individually. This method could directly display the variation of the CHD fetal heart clearly and comprehensively help us to understand the complex fetal cardiac malformation from the internal structure of the vascular malformation which was consolidated by the anatomical basis of the fetal heart. This study could improve the integrity and accuracy of the prenatal cardiac ultrasound examination tremendously.

A new metric of inclusive fitness predicts the human mortality profile

Biological species have evolved characteristic patterns of age-specific mortality across their life spans. If these mortality profiles are shaped by natural selection they should reflect underlying variation in the fitness effect of mortality with age. Direct fitness models, however, do not accurately predict the mortality profiles of many species. For several species, including humans, mortality rates vary considerably before and after reproductive ages, during life-stages when no variation in direct fitness is possible. Variation in mortality rates at these ages may reflect indirect effects of natural selection acting through kin. To test this possibility we developed a new two-variable measure of inclusive fitness, which we term the extended genomic output or EGO. Using EGO, we estimate the inclusive fitness effect of mortality at different ages in a small hunter-gatherer population with a typical human mortality profile. EGO in this population predicts 90% of the variation in age-specific mortality. This result represents the first empirical measurement of inclusive fitness of a trait in any species. It shows that the pattern of human survival can largely be explained by variation in the inclusive fitness cost of mortality at different ages. More generally, our approach can be used to estimate the inclusive fitness of any trait or genotype from population data on birth dates and relatedness.

Age at referral and mortality from critical congenital heart disease

BACKGROUND AND OBJECTIVE

Newborn pulse oximetry screening is recommended to promote early referral of neonates with critical congenital heart disease (CCHD) and reduce mortality; however, the impact of late referral on mortality is not well defined. The purpose of this population-based study was to describe the association between timing of referral to a cardiac center and mortality in 2360 liveborn neonates with CCHD.

METHODS

Neonates with CCHD born before pulse oximetry screening (1996-2007) were selected from the Texas Birth Defects Registry and linked to state birth and death records. Age at referral was ascertained from date of first cardiac procedure at a cardiac center. Logistic and Cox proportional hazards regression models were used to estimate factors associated with late referral and mortality; the Kaplan-Meier method was used to estimate 3-month survival.

RESULTS

Median age at referral was 1 day (25th-75th percentile: 0-6 days). Overall, 27.5% (649 of 2360) were referred after age 4 days and 7.5% (178 of 2360) had no record of referral. Neonatal mortality was 18.1% (277 of 1533) for those referred at 0 to 4 days of age, 9.0% (34 of 379) for those referred at 5 to 27 days of age, and 38.8% (69 of 178) for those with no referral. No improvement in age at referral was found across the 2 eras within 1996-2007.

CONCLUSIONS

A significant proportion of neonates with CCHD experienced late or no referral to cardiac specialty centers, accounting for a significant number of the deaths. Future population-based studies are needed to determine the benefit of pulse oximetry screening on mortality and morbidity.

Opportunity for selection in human health

Natural selection defined by differential survival and reproduction of individuals in populations is influenced by genetic, developmental, and environmental factors operating at every age and stage in human life history: generation of gametes, conception, birth, maturation, reproduction, senescence, and death. Biological systems are built upon a hierarchical organization nesting subcellular organelles, cells, tissues, and organs within individuals, individuals within families, and families within populations, and the latter among other populations. Natural selection often acts simultaneously at more than one level of biological organization and on specific traits, which we define as multilevel selection. Under this model, the individual is a fundamental unit of biological organization and also of selection, imbedded in a larger evolutionary context, just as it is a unit of medical intervention imbedded in larger biological, cultural, and environmental contexts. Here, we view human health and life span as necessary consequences of natural selection, operating at all levels and phases of biological hierarchy in human life history as well as in sociological and environmental milieu. An understanding of the spectrum of opportunities for natural selection will help us develop novel approaches to improving healthy life span through specific and global interventions that simultaneously focus on multiple levels of biological organization. Indeed, many opportunities exist to apply multilevel selection models employed in evolutionary biology and biodemography to improving human health at all hierarchical levels. Multilevel selection perspective provides a rational theoretical foundation for a synthesis of medicine and evolution that could lead to discovering effective predictive, preventive, palliative, potentially curative, and individualized approaches in medicine and in global health programs.

National trend in congenital heart disease mortality in China during 2003 to 2010: a population-based study

BACKGROUND

Previous studies suggest that mortality from congenital heart diseases (CHDs) is declining in the United States. But we do not know what the CHD mortality trend is in China, especially the rural versus urban patterns. Our study aimed to determine recent changes in death caused by CHD in China and describe CHD mortality in rural and urban Chinese populations.

METHODS

The data source was the China Ministry of Health 2003 to 2010 annual reports. Mortality was defined as death caused by CHD. Mortality rates for each year were calculated per 10,000,000 person-years. Poisson regression and descriptive analyses were conducted for overall trend and subgroup analysis was conducted by sex, age, and urban versus rural residency to understand potential disparities in mortality.

RESULTS

From 2003 to 2010, the overall mortality rate increased from 141 per 10,000,000 person-years in 2003 to 229 per 10,000,000 person-years in 2010, a 62.4% relative increase. This represents a region-sex adjusted annual increase of 9% (incidence rate ratio, 1.09; 95% confidence interval, 1.09-1.10). The increase in CHD mortality was not uniformly observed across age groups, urban versus rural residence, and sex. The relative increases were 65.3%, 212.2%, and 131.7% for ages 1 to 10 years, 21 to 64 years, and 65 years or older groups, respectively. Urban areas had a relative increase of 154.5% versus 5.3% for rural areas. Females who lived in an urban environment had a relative increase of 313.5%.

CONCLUSIONS

Our observation showed an obvious increasing trend of CHD mortality in China. What is more, the increase in CHD mortality was not uniformly observed across subgroups. Such information is needed for strategy-making procedures.

Translational paradigms in scientific and clinical imaging of cardiac development

Congenital heart defects (CHD) are the most prevalent congenital disease, with 45% of deaths resulting from a congenital defect due to a cardiac malformation. Clinically significant CHD permit survival upon birth, but may become immediately life threatening. Advances in surgical intervention have significantly reduced perinatal mortality, but the outcome for many malformations is bleak. Furthermore, patients living while tolerating a CHD often acquire additional complications due to the long-term systemic blood flow changes caused by even subtle anatomical abnormalities. Accurate diagnosis of defects during fetal development is critical for interventional planning and improving patient outcomes. Advances in quantitative, multidimensional imaging are necessary to uncover the basic scientific and clinically relevant morphogenetic changes and associated hemodynamic consequences influencing normal and abnormal heart development. Ultrasound is the most widely used clinical imaging technology for assessing fetal cardiac development. Ultrasound-based fetal assessment modalities include motion mode (M-mode), two dimensional (2D), and 3D/4D imaging. These datasets can be combined with computational fluid dynamics analysis to yield quantitative, volumetric, and physiological data. Additional imaging modalities, however, are available to study basic mechanisms of cardiogenesis, including optical coherence tomography, microcomputed tomography, and magnetic resonance imaging. Each imaging technology has its advantages and disadvantages regarding resolution, depth of penetration, soft tissue contrast considerations, and cost. In this review, we analyze the current clinical and scientific imaging technologies, research studies utilizing them, and appropriate animal models reflecting clinically relevant cardiogenesis and cardiac malformations. We conclude with discussing the translational impact and future opportunities for cardiovascular development imaging research.

Maternal smoking and congenital heart defects in the Baltimore-Washington Infant Study

OBJECTIVE

We investigated associations between maternal cigarette smoking during the first trimester and the risk of congenital heart defects (CHDs) among the infants.

METHODS

The Baltimore-Washington Infant Study was the first population-based case-control study of CHDs conducted in the United States. Case and control infants were enrolled during the period 1981-1989. We excluded mothers with overt pregestational diabetes and case mothers whose infants had noncardiac anomalies (with the exception of atrioventricular septal defects with Down syndrome) from the analysis, which resulted in 2525 case and 3435 control infants. Self-reported first-trimester maternal cigarette consumption was ascertained via an in-person interview after delivery. Associations for 26 different groups of CHDs with maternal cigarette consumption were estimated by using logistic regression models. Odds ratios (ORs) corresponded to a 20-cigarette-per-day increase in consumption.

RESULTS

We observed statistically significant positive associations between self-reported first-trimester maternal cigarette consumption and the risk of secundum-type atrial septal defects (OR: 1.36 [95% confidence interval (CI): 1.04-1.78]), right ventricular outflow tract defects (OR: 1.32 [95% CI: 1.06-1.65]), pulmonary valve stenosis (OR: 1.35 [95% CI: 1.05-1.74]), truncus arteriosus (OR: 1.90 [95% CI: 1.04-3.45]), and levo-transposition of the great arteries (OR: 1.79 [95% CI: 1.04-3.10]). A suggestive association was observed for atrioventricular septal defects among infants without Down syndrome (OR: 1.50 [95% CI: 0.99-2.29]).

CONCLUSIONS

These findings add to the existing body of evidence that implicates first-trimester maternal cigarette smoking as a modest risk factor for select CHD phenotypes.

Mortality resulting from congenital heart disease among children and adults in the United States, 1999 to 2006

BACKGROUND

Previous reports suggest that mortality resulting from congenital heart disease (CHD) among infants and young children has been decreasing. There is little population-based information on CHD mortality trends and patterns among older children and adults.

METHODS AND RESULTS

We used data from death certificates filed in the United States from 1999 to 2006 to calculate annual CHD mortality by age at death, race-ethnicity, and sex. To calculate mortality rates for individuals ≥1 year of age, population counts from the US Census were used in the denominator; for infant mortality, live birth counts were used. From 1999 to 2006, there were 41,494 CHD-related deaths and 27,960 deaths resulting from CHD (age-standardized mortality rates, 1.78 and 1.20 per 100,000, respectively). During this period, mortality resulting from CHD declined 24.1% overall. Mortality resulting from CHD significantly declined among all race-ethnicities studied. However, disparities persisted; overall and among infants, mortality resulting from CHD was consistently higher among non-Hispanic blacks compared with non-Hispanic whites. Infant mortality accounted for 48.1% of all mortality resulting from CHD; among those who survived the first year of life, 76.1% of deaths occurred during adulthood (≥18 years of age).

CONCLUSIONS

CHD mortality continued to decline among both children and adults; however, differences between race-ethnicities persisted. A large proportion of CHD-related mortality occurred during infancy, although significant CHD mortality occurred during adulthood, indicating the need for adult CHD specialty management.

Abnormal first-trimester ductus venosus blood flow: a marker of cardiac defects in fetuses with normal karyotype and nuchal translucency

OBJECTIVE

To evaluate the independent contribution of ductus venosus (DV) blood flow assessment at 11-14 weeks' gestation to the prediction of congenital heart defects (CHD) in chromosomally normal fetuses, irrespective of the value of the nuchal translucency thickness (NT).

METHODS

During a 4-year period, all singleton pregnancies from 11 + 0 to 13 + 6 weeks' gestation were scanned for NT and DV blood flow in a tertiary center. Abnormal DV blood flow was defined as either absent or reversed flow during atrial contraction (AR-DV). Fetal echocardiography was performed in all cases with either NT > 99(th) percentile or AR-DV. Follow-up was assessed by postnatal examination or autopsy in cases of termination of pregnancy or perinatal death.

RESULTS

A total of 6120 pregnancies were scanned at a median gestational age of 12 weeks, and 45 cases of CHD were detected. AR-DV was found in 206 fetuses, of which 145 (70.4%) had a normal karyotype. Among fetuses with AR-DV and normal karyotype, 11 cases of CHD were diagnosed, giving a sensitivity of 24.4%, a positive predictive value of 7.6% and an odds ratio of 9.8. Increased NT (> 99(th) centile) was present in 55 of the 145 (37.9%) cases with AR-DV and normal karyotype, and in 6/11 (54.5%) of those with CHD. Thus, the group of 90 fetuses with abnormal DV blood flow and normal NT contained five cases of CHD, for a sensitivity of 11.1%, a positive predictive value of 5.5% and an odds ratio of 8.5. Right-heart anomalies were predominant in those cases with isolated AR-DV (4/5), but no specific CHD pattern was found in those with increased NT. The detection rate of CHD by the combined use of increased NT and/or AR-DV in the first trimester improved from 28.9% (13/45) to 40.0% (18/45).

CONCLUSIONS

In experienced hands, abnormal DV blood flow in the first trimester is an independent predictor of CHD and should constitute an indication for early echocardiography. In this study, the use of DV blood flow assessment increased early detection of CHD by 11% with respect to the use of NT measurement alone.

Determinants of survival in children with congenital abnormalities: a long-term population-based cohort study

BACKGROUND

Today more children with birth defects survive early childhood because of improved medical care; however, little information is available about patterns of long-term mortality and survival in this population. In particular, it is not clear whether other birth characteristics, apart from birth defects, have any role in their mortality.

METHODS

Two large cohorts of children with and without birth defects were followed for up to 17 years. More than 45,000 children with birth defects, and 45,000 matched children without birth defects born in Ontario between 1979 and 1986 were followed. Throughout the study period long-term survival rates and the risk of death were compared between the 2 cohorts. Birth characteristics were also examined to determine their effect on the risk of death.

RESULTS

During the study the deaths of 3620 and 301 children with and without birth defects, respectively, were recorded, indicating that those with birth defects had a 13 times higher rate of mortality (relative risk [RR], 12.9, 95% confidence interval [CI], 12.1-13.7). Mortality rates in the birth-defects cohort remained higher even after 10-15 years. In both groups children of low gestational age and low birth weight had a higher risk of death. There was a strong dose-response relationship between the number of defects and the risk of death.

CONCLUSIONS

Children born with abnormalities face many challenges throughout their lifetimes. If they survive the high mortality risk of the first year of life, they still have to face the considerably higher risk of death in the years to come. In addition to birth defects, other birth characteristics play an independent role in their mortality. These indicators could be used to identify high-risk children.

A societal outcomes map for health research and policy

The linkages between decisions about health research and policy and actual health outcomes may be extraordinarily difficult to specify. We performed a pilot application of a "road mapping" and technology assessment technique to perinatal health to illustrate how this technique can clarify the relations between available options and improved health outcomes. We used a combination of data-mining techniques and qualitative analyses to set up the underlying structure of a societal health outcomes road map. Societal health outcomes road mapping may be a useful tool for enhancing the ability of the public health community, policymakers, and other stakeholders, such as research administrators, to understand health research and policy options.

The effect of terminations of pregnancy for fetal abnormalities on trends in mortality to one year of age in Western Australia

Summary highlighted the contribution of birth defects. Over this time there has also been an increasing number of terminations of pregnancy for fetal abnormality. However, the effect of these terminations on mortality rates in Australia has not yet been estimated. The Western Australian Birth Defects Registry (BDR) records all birth defects that are diagnosed in stillbirths, livebirths and in pregnancies terminated because of a fetal abnormality. All cases on the BDR over the period 1980-98 were categorised into one of eight main birth defect groups and analysed in four time periods to show trends. Linkage provided information on deaths to one year of age, defined as perinatal plus postneonatal deaths. The proportion of terminations for fetal abnormality that would have resulted in a death before one year of age was estimated in two ways. The first method used the proportion of births with a birth defect in each diagnostic category that resulted in a death. The second method involved determination of likelihood of survival to one year of all terminations for fetal abnormality through independent review by two experts. Whilst mortality to one year of age for all birth defects has declined from 4.36/1000 births in 1980-84 to 2.75/1000 births in 1995-98, terminations of pregnancies for fetal abnormalities increased from 1.19/1000 births to 4.70/1000 births. After including the estimated mortality associated with terminations for fetal abnormality, the decline in mortality to one year of age associated with birth defects from 1980 to 1998 changed from a 37% reduction to a 15% reduction based on observed mortality 1980-84, and an 11% increase in mortality based on individual case review, highlighting the importance of considering terminations in mortality analyses.

Proximity of residence to trichloroethylene-emitting sites and increased risk of offspring congenital heart defects among older women

BACKGROUND

Previous studies suggest that trichloroethylene (TCE) is a selective cardiac teratogen. We tested the hypothesis that the odds of maternal residence close to TCE-emitting sites would be greater among infants with congenital heart defects (CHDs) than among infants without CHDs.

METHODS

We conducted a case-control study of 4025 infants, identified from hospital and birth records, born from 1997 to 1999 to Milwaukee, Wisconsin mothers. A geographic information system was used to calculate distances between maternal residences and TCE sites. We used classification tree analysis to determine appropriate values by which to dichotomously categorize mothers by TCE exposure (exposed: residence within 1.32 miles of at least one TCE site) and age (older: >/=38 years), and logistic regression to test for CHD risk factors.

RESULTS

The proportion of mothers who were both older and had presumed TCE exposure was more than six-fold greater among case infants than among control infants (3.3% [8/245] versus 0.5% [19/3780]). When adjusted for other variables, CHD risk was over three-fold greater among infants of older, exposed mothers compared to infants of older, nonexposed mothers (adjusted OR, 3.2; 95% CI, 1.2-8.7). Older maternal age, alcohol use, chronic hypertension, and preexisting diabetes were each associated with CHDs (adjusted ORs, 1.9, 2.1, 2.8, 4.1; 95% CIs, 1.1-3.5, 1.1-4.2, 1.2-6.7, 1.5-11.2, respectively), but residence close to TCE sites alone was not.

CONCLUSIONS

Our findings suggest that maternal age and TCE exposure interact to increase CHD risk, although the mechanism by which this occurs is unknown. A prospective study is underway to confirm this finding.

Descriptive epidemiology of selected congenital heart defects, Hawaii, 1986-1999

Congenital heart defects are the most common type of birth defect and contribute the most to infant mortality due to birth defects. This study examined the relationship between several demographic factors and selected congenital heart defects among the unique multiethnic population in Hawaii during 1986-99, using data from a population-based birth defects registry. Rates were significantly higher in 1993-99 than in 1986-92 for transposition of the great arteries and Ebstein's anomaly, and significantly lower for tetralogy of Fallot. Significantly elevated rates were found with maternal age of > or =35 years for ventricular septal defect, atrial septal defect, endocardial cushion defect, and hypoplastic left heart syndrome. When cases with a known chromosomal abnormality were excluded, elevated rates among the older maternal age group remained for ventricular septal defect, atrial septal defect, and hypoplastic left heart syndrome. Whites had significantly higher rates than one or more of the other racial/ethnic groups for Ebstein's anomaly and coarctation of aorta, and significantly lower rates for tetralogy of Fallot, atrial septal defect, pulmonary valve atresia/stenosis, tricuspid valve atresia/stenosis, and anomalous pulmonary venous return. Significantly higher rates were found among males for transposition of great arteries, aortic valve stenosis, and interrupted aortic arch and, among females, for ventricular septal defect, endocardial cushion defect, and anomalous pulmonary venous return. Some of these differences were consistent with the literature while others were not.

Echocardiographic evaluation of asymptomatic parental and sibling cardiovascular anomalies associated with congenital left ventricular outflow tract lesions

OBJECTIVE

Left ventricular outflow tract obstructive (LVOTO) malformations are a leading cause of infant mortality from birth defects. Genetic mechanisms are likely, and there may be a higher rate of asymptomatic LVOTO anomalies in relatives of affected children. This study sought to define the incidence of cardiac anomalies in first-degree relatives of children with congenital aortic valve stenosis (AVS), coarctation of the aorta (CoA), and hypoplastic left heart syndrome (HLHS).

METHODS

A total of 113 probands with a nonsyndromic LVOTO malformation of AVS (n = 25), BAV (n = 3), CoA (n = 52), HLHS (n = 30), and aortic hypoplasia with mitral valve atresia (n = 2) were ascertained through chart review or enrolled at the time of diagnosis. Echocardiography was performed on 282 asymptomatic first-degree relatives.

RESULTS

Four studies had poor acoustic windows, leaving 278 studies for analysis. BAV were found in 13 (4.68%) first-degree relatives. The relative risk of BAV in the relatives was 5.05 (95% confidence interval: 2.2-11.7), and the broad sense heritability was 0.49, based on a general population frequency of 0.9%. BAV was more common in multiplex families compared with sporadic cases. An additional 32 relatives had anomalies of the aorta, aortic valve, left ventricle, or mitral valve.

CONCLUSIONS

The presence of an LVOTO lesion greatly increases the risk of identifying BAV in a parent or sibling, providing additional support for a complex genetic cause. The parents and siblings of affected patients should be screened by echocardiography as the presence of an asymptomatic BAV may carry a significant long-term health risk.

Survival of children born with congenital anomalies

AIM

To describe the survival to age 5 years of children born with congenital anomalies.

METHODS

Between 1980 and 1997, 6153 live born cases of congenital anomaly were diagnosed and registered by the population based Glasgow Register of Congenital Anomalies. They were retrospectively followed to assess their survival status from birth up to the age of 5 years.

RESULTS

The proportions of all live born infants with congenital anomalies surviving to the end of the first week, and first and fifth year were 94%, 89%, and 88%, respectively. Survival to age 5, the end point of follow up, was significantly poorer for infants with chromosomal anomalies (48%) compared to neural tube defects (72%), respiratory system anomalies (74%), congenital heart disease (75%), nervous system anomalies (77%), and Down's syndrome (84%).

CONCLUSION

Although almost 90% of all live born infants with congenital anomalies survive to 5 years, there are notable variations in survival between anomaly types. Our findings should be useful for both clinicians and geneticists to assess the prognosis of congenital anomalies. This information is also important for affected families and for the planning of health care needs for this high risk population.

Joint models for toxicology studies with dose-dependent number of implantations

Many chemicals interfere with the natural reproductive processes in mammals. The chemicals may prevent the fertilization of an egg or keep a zygote from implanting in the uterine wall. For this reason, toxicology studies with pre-implantation exposure often exhibit a dose-related trend in the number of observed implantations per litter. Standard methods for analyzing developmental toxicology studies are conditioned on the number of implantations in the litter and therefore cannot estimate this effect of the chemical on the reproductive process. This article presents a joint modeling approach to estimating risk in toxicology studies with pre-implantation exposure. In the joint modeling approach, both the number of implanted fetuses and the outcome of each implanted fetus is modeled. Using this approach we show how to estimate the overall risk of a chemical that incorporates the risk of lost implantation due to pre-implantation exposure. Our approach has several distinct advantages over previous methods: (1) it is based on fitting a model for the observed data and, therefore, diagnostics of model fit and selection apply; (2) all assumptions are explicitly stated; and (3) it can be fit using standard software packages We illustrate our approach by analyzing a dominant lethal assay data set (Luning et al., 1966, Mutation Research, 3, 444-451) and compare ourresults with those of Rai and Van Ryzin (1985, Biometrics, 41,1-9) and Dunson (1998, Biometrics, 54, 558-569). In a simulation study, our approach has smaller bias and variance than the multiple imputation procedure of Dunson.

Reproductive decisions of parents of children with metabolic disorders

The Interaction Model of Client Health Behavior (IMCHB) served as a guide for variable selection and instrument development for telephone interviews with 230 parents of children with metabolic disorders. Sociodemographic, psycho-affective and client-professional interaction variables were examined in relation to three outcomes: (1) receptivity to future prenatal diagnosis (56% were receptive); (2) likelihood of terminating an affected pregnancy (10% would); and (3) whether or not the parent had taken measures to prevent another affected pregnancy (41% had). All three outcomes were significantly correlated with higher scores on the Parent Stress Index, lower scores on the Vineland Adaptive Behavior Scales, fewer persons in the parent's social support network, greater worry about the living child's future and greater perceived difficulty meeting the child's extra care needs. A regression model constructed to explain taking measures to prevent a future affected pregnancy illustrated the usefulness of the IMCHB in research that involves multiple interacting variables on health outcomes. Few of the parents (7.4%) reported an interaction with a genetic counsellor, highlighting the need for practitioners from multiple disciplines to be adequately educated in principles of genetics, especially the psychological and affective aspects of counselling.

Racial and temporal variations in the prevalence of heart defects

BACKGROUND

Documenting the prevalence and trends of congenital heart defects provides useful data for pediatric practice, health-care planning, and causal research. Yet, most population-based studies use data from the 1970s and 1980s. We sought to extend into more recent years the study of temporal and racial variations of heart defects occurrence in a well-defined population.

METHODS

We used data from the Metropolitan Atlanta Congenital Defects Program, a population-based registry with active case ascertainment from multiple sources. Heart defects were identified among liveborn infants up to 1 year old, among stillborn infants, and among pregnancy terminations to mothers residing in metropolitan Atlanta.

RESULTS

From 1968 through 1997, the registry ascertained 5813 major congenital heart defects among 937 195 infants, for a prevalence of 6.2 per 1000. The prevalence increased to 9.0 per 1000 births in 1995 through 1997. The prevalence of ventricular septal defects, tetralogy of Fallot, atrioventricular septal defects, and pulmonary stenosis increased, whereas that of transposition of the great arteries decreased. For some defects, prevalence and trends varied by race.

CONCLUSIONS

The prevalence of congenital heart defects is increasing. Whereas most findings likely result from improved case ascertainment and reporting, others might be because of changes in the distribution of risk factors in the population. The basis of the racial variations is incompletely understood.