Prevalence Of Spina Bifida Research Articles

Global Birth Prevalence of Spina Bifida by Folic Acid Fortification Status: A Systematic Review and Meta-Analysis

Background. Birth defects remain a significant source of worldwide morbidity and mortality. Strong scientific evidence shows that folic acid fortification of a region’s food supply leads to a decrease in spina bifida (a birth defect of the spine). Still, many countries around the world have yet to approve mandatory fortification through government legislation. Objectives. We sought to perform a systematic review and meta-analysis of period prevalence of spina bifida by folic acid fortification status, geographic region, and study population. Search methods. An expert research librarian used terms related to neural tube defects and epidemiology from primary research from 1985 to 2010 to search in EMBASE and MEDLINE. We searched the reference lists of included articles and key review articles identified by experts. Selection criteria. Inclusion criteria included studies in English or French reporting on prevalence published between January 1985 and December 2010 that (1) were primary research, (2) were population-based, and (3) reported a point or period prevalence estimate of spina bifida (i.e., prevalence estimate with confidence intervals or case numerator and population denominator). Two independent reviewers screened titles and abstracts for eligible articles, then 2 authors screened full texts in duplicate for final inclusion. Disagreements were resolved through consensus or a third party. Data collection and analysis. We followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses, or PRISMA, abstracting data related to case ascertainment, study population, folic acid fortification status, geographic region, and prevalence estimate independently and in duplicate. We extracted overall data and any subgroups reported by age, gender, time period, or type of spina bifida. We classified each period prevalence estimate as “mandatory” or “voluntary” folic acid fortification according to each country’s folic acid fortification status at the time data were collected (as determined by a well-recognized fortification monitoring body, Food Fortification Initiative). We determined study quality on the basis of sample representativeness, standardization of data collection and birth defect assessment, and statistical analyses. We analyzed study-level period prevalence estimates by using a random effects model (α level of < 0.05) for all meta-analyses. We stratified pooled period prevalence estimates by birth population, fortification status, and continent. Results. Of 4078 studies identified, we included 179 studies in the systematic review and 123 in a meta-analysis. In studies of live births (LBs) alone, period prevalences of spina bifida were (1) lower in geographical regions with mandatory (33.86 per 100 000 LBs) versus voluntary (48.35 per 100 000 LBs) folic acid fortification, and (2) lower in studies of LBs, stillbirths, and terminations of pregnancy in regions with mandatory (35.22 per 100 000 LBs) versus voluntary (52.29 per 100 000 LBs) fortification. In LBs, stillbirths, and terminations of pregnancy studies, the lowest pooled prevalence estimate was in North America (38.70 per 100 000). Case ascertainment, surveillance methods, and reporting varied across these population-based studies. Conclusions. Mandatory legislation enforcing folic acid fortification of the food supply lags behind the evidence, particularly in Asian and European countries. This extensive literature review shows that spina bifida is significantly more common in world regions without government legislation regulating full-coverage folic acid fortification of the food supply (i.e., Asia, Europe) and that mandatory folic acid fortification resulted in a lower prevalence of spina bifida regardless of the type of birth cohort. African data were scarce, but needed, as many African nations are beginning to adopt folic acid legislation.

Global Birth Prevalence of Spina Bifida by Folic Acid Fortification Status: A Systematic Review and Meta-Analysis.

Birth defects remain a significant source of worldwide morbidity and mortality. Strong scientific evidence shows that folic acid fortification of a region's food supply leads to a decrease in spina bifida (a birth defect of the spine). Still, many countries around the world have yet to approve mandatory fortification through government legislation. We sought to perform a systematic review and meta-analysis of period prevalence of spina bifida by folic acid fortification status, geographic region, and study population. An expert research librarian used terms related to neural tube defects and epidemiology from primary research from 1985 to 2010 to search in EMBASE and MEDLINE. We searched the reference lists of included articles and key review articles identified by experts. Inclusion criteria included studies in English or French reporting on prevalence published between January 1985 and December 2010 that (1) were primary research, (2) were population-based, and (3) reported a point or period prevalence estimate of spina bifida (i.e., prevalence estimate with confidence intervals or case numerator and population denominator). Two independent reviewers screened titles and abstracts for eligible articles, then 2 authors screened full texts in duplicate for final inclusion. Disagreements were resolved through consensus or a third party. We followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses, or PRISMA, abstracting data related to case ascertainment, study population, folic acid fortification status, geographic region, and prevalence estimate independently and in duplicate. We extracted overall data and any subgroups reported by age, gender, time period, or type of spina bifida. We classified each period prevalence estimate as "mandatory" or "voluntary" folic acid fortification according to each country's folic acid fortification status at the time data were collected (as determined by a well-recognized fortification monitoring body, Food Fortification Initiative). We determined study quality on the basis of sample representativeness, standardization of data collection and birth defect assessment, and statistical analyses. We analyzed study-level period prevalence estimates by using a random effects model (α level of < 0.05) for all meta-analyses. We stratified pooled period prevalence estimates by birth population, fortification status, and continent. Of 4078 studies identified, we included 179 studies in the systematic review and 123 in a meta-analysis. In studies of live births (LBs) alone, period prevalences of spina bifida were (1) lower in geographical regions with mandatory (33.86 per 100,000 LBs) versus voluntary (48.35 per 100,000 LBs) folic acid fortification, and (2) lower in studies of LBs, stillbirths, and terminations of pregnancy in regions with mandatory (35.22 per 100,000 LBs) versus voluntary (52.29 per 100,000 LBs) fortification. In LBs, stillbirths, and terminations of pregnancy studies, the lowest pooled prevalence estimate was in North America (38.70 per 100,000). Case ascertainment, surveillance methods, and reporting varied across these population-based studies. Mandatory legislation enforcing folic acid fortification of the food supply lags behind the evidence, particularly in Asian and European countries. This extensive literature review shows that spina bifida is significantly more common in world regions without government legislation regulating full-coverage folic acid fortification of the food supply (i.e., Asia, Europe) and that mandatory folic acid fortification resulted in a lower prevalence of spina bifida regardless of the type of birth cohort. African data were scarce, but needed, as many African nations are beginning to adopt folic acid legislation.

Preventable spina bifida and anencephaly in Europe.

Promotion of voluntary folic acid supplement use among women of reproductive age has been proven to be ineffective in lowering the risk of neural tube defects in Europe. Using surveillance data from all births covered by the full member countries of the European Surveillance of Congenital Anomalies (EUROCAT), we estimated the total prevalence of spina bifida and anencephaly per 10,000 births between 2000 and 2010. We also estimated additional lifetime direct medical costs among individuals with spina bifida, compared with those without, in Germany for the year 2009. During the study period, there were 7478 documented cases of spina bifida and anencephaly among the 9,161,189 births, with an estimated average combined prevalence of 8.16 per 10,000 births (95% confidence interval, 7.98 - 8.35). For the 241 spina bifida-affected live births in 2009 in Germany, the estimated additional lifetime direct medical costs compared with non-spina bifida affected births were €65.5 million. Assuming a 50% reduction in the prevalence if folic acid has been provided to all women before pregnancy, 293 spina bifida cases could have been prevented in Germany in 2009. The estimated lifetime direct medical cost saving for the live births in 2009 was €32.9 million assuming a 50% reduction, or €26.1 million assuming a 40% risk reduction. Europe has an epidemic of spina bifida and anencephaly compared with countries with mandatory folic acid fortification policy. Primary prevention through mandatory folic acid fortification would considerably reduce the number of affected pregnancies, and associated additional costs.

Ethnic Pattern of Origin of Children with Spina Bifida Managed at the University Teaching Hospital and Beit Cure Hospital, Lusaka, Zambia 2001-2010

The incidence of spina bifida (SB) is known to differ among regions. Very little has been reported about the relationship between the incidence of SB and ethnic patterns of origin in Zambia except for the general impression that it is prevalent. The aim of the study was to establish the ethnic pattern of origin of children with SB in Zambia. It was a retrospective cross sectional study. Using a checklist, data was collected from clinical files of children with SB from the University Teaching Hospital (UTH) and Beit Cure Hospital (BCH) from 2001-2010. Descriptive statistical analysis was done in SPSS version 17. A total of 253 children with SB were identified of whom 88 (35%) of them originally came from the Southern Province of the country while the lowest province was the North-Western Province with 7 (3%). Further, a total of 77 (30%) children were referred from the Southern Province of the country and the lowest province that was represented was the North-Western Province with 5 (2%). Observed is the evidence that SB is very prevalent in the Southern Province of the country. With the presence of Uranium in the Southern Province of Zambia, a serious study ought to be done to investigate the possible link of the pollutant with the prevalence of SB in the region. It is essential that the government looks seriously at Uranium Mines being operated in the Province.

Prevalence of congenital malformations at birth in Chilean maternity hospitals

The Latin American Collaborative Study of Congenital Malformations (ECLAMC) is an epidemiological surveillance system operating in 11 South American countries since 1969. To analyze the Congenital Malformation prevalence rate at birth from 2001 to 2010 in Chilean Hospitals participating in ECLAMC. To compare these rates with those of the period 1982-1994. Review of the ECLAMC database, which contains information about 282.568 newborns, 2.110 of them stillbirths (0.75%) from 13 Maternity hospitals. In the study period, 10.925 newborns had congenital malformations (3.9 %). Their frequency was lower in live newborns than stillbirths (3.8 and 15.3%, respectively). Compared with the 1982-1994 period, congenital malformation prevalence rates at birth were higher. They stabilized in approximately 4 %, from 1985 to 2010. The prevalence of some anomalies such as Down syndrome increased significantly. On the other hand, there was a reduction in the prevalence of spina bifida and anencephaly. Prevalence rates of congenital malformations at birth remained stable in the last 18 years in Chilean Hospitals participating in ECLAMC. However the prevalence of some malformations such as Down syndrome, Polydactyly, anotia-microtia, syndactyly and cleft palate have increased. The prevalence rates of spina bifida and anencephaly have decreased.

Assessing the prevalence of spina bifida and encephalocele in a Kenyan hospital from 2005-2010: implications for a neural tube defects surveillance system.

IntroductionNeural tube defects such as anencephaly, spina bifida, and encephalocele are congenital anomalies of the central nervous system. Data on the prevalence of neural tube defects in Kenya are limited. This study characterizes and estimates the prevalence of spina bifida and encephalocele reported in a referral hospital in Kenya from 2005-2010.MethodsCases were defined as a diagnosis of spina bifida or encephalocele. Prevalence was calculated as the number of cases by year and province of residence divided by the total number of live-births per province.ResultsFrom a total of 6,041 surgical records; 1,184 (93%) had reported diagnosis of spina bifida and 88 (7%) of encephalocele. Estimated prevalence of spina bifida and encephalocele from 2005-2010 was 3.3 [95% Confidence Interval (CI): 3.1-3.5] cases per 10,000 live-births. The highest prevalence of cases were reported in 2007 with 4.4 (95% CI: 3.9-5.0) cases per 10,000 live-births. Rift Valley province had the highest prevalence of spina bifida and encephalocele at 6.9 (95% CI: 6.3-7.5) cases per 10,000 live-births from 2005-2010.ConclusionPrevalence of spina bifida and encephalocele is likely underestimated, as only patients seeking care at the hospital were included. Variations in regional prevalence could be due to referral patterns and healthcare access. Implementation of a neural tube defects surveillance system would provide a more thorough assessment of the burden of neural tube defects in Kenya.

A description of spina bifida cases and co‐occurring malformations, 1976–2011

Mandatory folic acid fortification in the United States corresponded with a decline in the prevalence of spina bifida (SB). The aim of this study was to describe the epidemiologic characteristics of isolated versus non-isolated SB cases in both pre- and post-fortification periods. SB cases in the Slone Epidemiology Center Birth Defects Study from 1976 to 2011 without chromosomal anomalies and syndromes were included. A maternal interview, conducted within 6 months of delivery, collected information on demographics, reproductive history, diet, and supplement use. Daily folic acid intake in the periconceptional period was calculated using both dietary and supplement information and categorized as low intake (<400 µg/day) or high intake (≥400 µg/day). SB cases (n = 1170) were classified as isolated (80.4%) or non-isolated (19.1%). Non-isolated cases were further divided into subgroups based on accompanying major malformations (midline, renal, genital, heart, laterality). Compared to non-isolated cases, isolated cases were more likely to be white, non-Hispanic and have more than 12 years of education. Cases in the renal, genital, and heart subgroups had the lowest proportions of mothers with a high folic acid intake. The change from pre- to post-fortification was associated with a decrease in the proportion of isolated cases from 83% to 72%, though in both periods isolated cases were more likely to be female and their mothers were more likely to have high folic acid intake. These findings highlight the importance of separating isolated and non-isolated cases in etiologic research of SB.

Estimate of the potential impact of folic acid fortification of corn masa flour on the prevention of neural tube defects.

Hispanics in the US have a higher prevalence of neural tube defect (NTD) -affected pregnancies than non-Hispanic whites, and lower median total folic acid (FA) intake. FA fortification of corn masa flour (CMF) is a policy-level intervention for NTD prevention; however, the impact on NTD prevalence has not been estimated. We developed a model to estimate the percentage reduction in prevalence of spina bifida and anencephaly (NTDs) that could occur with FA fortification of CMF. Model inputs included estimates of the percentage reduction in United States NTD prevalence attributed to FA fortification of enriched cereal grain products (1995-1996 vs. 1998-2002), the increase in median FA intake after enriched cereal grain product fortification, and the estimated increase in median FA intake that could occur with CMF fortification at the same level as enriched cereal grain products (140 μg/100 g). We used Monte Carlo simulation to quantify uncertainty. We stratified analyses by racial/ethnic group and rounded results to the nearest 10. We estimated CMF fortification could prevent 30 Hispanic infants from having spina bifida (95% uncertainty interval: 0, 80) and 10 infants from having anencephaly (95% uncertainty interval: 0, 40) annually. The estimated impact among non-Hispanic whites and blacks was smaller. CMF fortification with FA could prevent from 0 to 120 infants, with the most likely value of approximately 40, from having spina bifida or anencephaly among Hispanics, the population most likely to benefit from the proposed intervention. While this estimated reduction is unlikely to be discernible using current birth defect surveillance methods, it still suggests an important benefit to the target population.

Analysis of spina bifida prevalence in Brazil in the period from 2001 to 2010

Analysis of spina bifida prevalence in Brazil in the period from 2001 to 2010

Contemporary Epidemiological Trends in Complex Congenital Genitourinary Anomalies

Anecdotal evidence suggests that complex congenital genitourinary anomalies are occurring less frequently. However, few epidemiological studies are available to confirm or refute this suggestion. The Kids' Inpatient Database (KID) is a national, all payer database of several million inpatient pediatric hospitalizations per year, including complicated and uncomplicated in-hospital births. We reviewed the 1997 to 2009 KID to determine the birth prevalence of spina bifida, posterior urethral valves, bladder exstrophy, epispadias, prune belly syndrome, ambiguous genitalia and imperforate anus. For posterior urethral valves and prune belly syndrome we limited our search to newborn males only. During the study period, there was a diagnosis of spina bifida in 3,413 neonates, bladder exstrophy in 214, epispadias in 1,127, ambiguous genitalia in 726, prune belly syndrome in 180, posterior urethral valves in 578 and imperforate anus in 4,040. We identified no significant change in the birth prevalence of spina bifida (from 33.9 new spina bifida births of 100,000 uncomplicated births to 29.0/100,000, p = 0.08), posterior urethral valves (from 10.4/100,000 to 11.0/100,000, p = 0.51), prune belly syndrome (from 4.8/100,000 to 3.3/100,000, p = 0.44) or ambiguous genitalia (from 5.82/100,000 to 5.87/100,000, p = 0.38). There was a significant decrease in the birth prevalence of bladder exstrophy (from 2.4/100,000 to 1.6/100,000 uncomplicated births, p = 0.01) and a significant increase in epispadias (from 8.0/100,000 to 11.6/100,000) and imperforate anus (from 33.6/100,000 to 35.0/100,000, each p = 0.04) during the study period. The birth prevalence of spina bifida, posterior urethral valves and prune belly syndrome appears to have been stable in the last 12 years. Epispadias, ambiguous genitalia and imperforate anus diagnoses in newborns became more common in the same period, while bladder exstrophy diagnoses became less common.

Ultrasound screening for fetal spina bifida: Bernard et al

340 American Journal of Obstetrics & Gynecology Twenty years ago, the US Public Health Service recommended that women of childbearing age ingest 400 mcg of folic acid daily to help prevent neural tube defects in their babies. To further ensure sufficient intake, the government mandated supplementation of enriched cereal grain products by January 1998. This simple measure is associated with a 31% drop in the prevalence of spina bifida and generally, an estimated 1000 fewer cases of neural tube defect per year. Still, about 1500 babies are born with spina bifida yearly in the United States. A new study suggests that basic measurements can predict diagnosis earlier in about half of affected pregnancies.

Do we really need a screening test for open spina bifida?

In a recent issue of the Journal were published a series of articles1-4 and an Opinion5 regarding possible approaches to early diagnosis of open spina bifida (SB) by way of a screening examination of the fetal brain posterior fossa, specifically the cerebral fourth ventricle, as imaged as an intracranial translucency (IT) between the brain stem and choroid plexus. Each of the studies applied a slightly different imaging approach and varying biometry to the target area, with the aim of flagging up suspected cases or ruling out SB during the late first trimester of pregnancy. The WHO defines certain criteria for screening tests6. The disease must be of sufficient prevalence and severity and should have a fixed spectrum of symptoms, the screening method should be simple and acceptable, screening should be accurate, confirmation and follow-up should be available, the disease should be treatable and screening should show improved outcome and a positive cost/benefit ratio. First and foremost, therefore, a screening test is performed because the definitive diagnostic test is too invasive, too expensive, too difficult technically, or otherwise unacceptable or unavailable to the general population. Screening acts as a ‘sieve’ (hence its name): screen-positive cases are caught in the sieve and are referred for further examination, i.e. either a definitive diagnostic test or more invasive, expensive or technically challenging screening. Clearly, prenatal diagnosis of SB as an entity fulfills the criteria of a target lesion for a screening test. SB prevalence is approximately 1:2000 and each case represents a significant cost to society in long-term care; it is treatable, i.e. avoidable, by pregnancy termination, or early treatment in-utero may ameliorate its damage. However, intrauterine repair of SB is performed only during the second half of the second trimester, at 23–26 weeks of gestation7, 8. Thus, whether the lesion was diagnosed in the first or early second trimester is irrelevant. The advantage of early diagnosis is only in earlier provision of pregnancy termination, when this is the parents' wish. Does screening for fetal IT, as an indicator for SB, fulfill the criteria of screening tests? Is it easier, more accurate or more acceptable to patients than is direct ultrasound scanning of the fetal spine at 11–13 weeks' gestation for diagnosis of SB? The authors of the various papers that appeared in the Journal did not show that their scanning method increased screening performance, was easier to perform or was more acceptable to patients compared with direct visualization of the fetal spine. What advantage, then, does the method confer? According to the authors, five or seven specified reference points must be imaged to visualize satisfactorily the IT, and all authors reported low success rates for satisfactory imaging of IT as well as low sensitivity of the test. No comparison was made with transvaginal imaging of the spine. It would seem that if image quality is sufficient to allow for IT imaging and measurement, direct imaging of the fetal spine would be possible, whether by transabdominal or transvaginal route. At these gestational ages, with the rapid changes of fetal position, or with simple bimanual manipulation, the whole spine can be visualized and SB or meningomyelocele can be diagnosed. In our center we have been performing late first- and early second-trimester targeted fetal organ scanning by the transvaginal route for about 20 years. Examination of the fetal spine is of course an integral part of this examination. During this period we have scanned about 15 000 fetuses and diagnosed about 20 cases of open SB, while we have not missed any; since this anomaly is subject to national registration, and because of the medicolegal climate here, we would be informed promptly if an undiagnosed case were to be delivered, whether in our hospital or elsewhere. In their recent Opinion5 Profs Chaoui and Nicolaides claim that the transvaginal approach is not acceptable for screening of SB. However, in the pyramid of prenatal diagnosis put forward by Nicolaides9, the first-trimester screening test includes transvaginal ultrasound to evaluate cervical length, and transvaginal ultrasound has also long been applied to uterine artery pulsatility index measurement. An overwhelming majority of women agree to undergo transvaginal ultrasound examination. We maintain that if women agree to transvaginal sonography for cervical length or uterine artery Doppler measurement, they will surely agree to it to exclude open SB. The early diagnosis of open SB can be achieved confidently by transvaginal scanning of the fetal spine as part of the 11–13-week scan, after measurement of uterine artery Doppler flow and cervical length measurement. A separate screening test for a marker for open SB is not necessary. Y. Gadot*, S. M. Cohen*, S. Yagel*, * Department of Obstetrics and Gynecology, Hadassah–Hebrew University Medical Centers, Jerusalem, Israel

A new national data collection for congenital anomalies in England and Wales

AimIn 2009 the National Congenital Anomaly System (NCAS) run by the Office for National Statistics (ONS) ceased data collection. In 2011, the Department of Health funded the British Isles Network...

P1-533 Trends in prevalence, pregnancy outcome, and survival of children born with Spina Bifida

IntroductionSpina bifida is a serious congenital anomaly associated with life-long disability. This study describes trends in the prevalence and survival of spina bifida, to 10 years, using data from a...

Targeted Preventive Care May Be Needed for Adults with Congenital Spine Anomalies

To compare hospitalizations caused by spina bifida-sensitive conditions, ambulatory care-sensitive conditions in adults with spina bifida and in the general population, our aim was to provide information about whether preventive health efforts already underway in the hospitalized general population are adequate for preventive care in spina bifida and congenital spine anomalies. Retrospective secondary data analysis. Records of hospitalized individuals who were 18 years of age and older. Comparison between individuals hospitalized with spina bifida and the general population using data from the California State Inpatient Database from the Healthcare Cost and Utilization Project for 2004 of adults. Prevalence of spina bifida-sensitive conditions and ambulatory care-sensitive conditions as reason for hospitalization and 30-day readmission. As compared with the general population, persons with spina bifida who were hospitalized in 2004 had a significantly greater number of hospitalizations, number of hospitalizations associated with both spina bifida-sensitive conditions and ambulatory care-sensitive conditions, and number of 30-day readmissions. Stratification by age shows that the admissions for spina bifida sensitive conditions were greater in persons with spina bifida than in the general population for all age groups. In contrast, only in the youngest age group did those with spina bifida experience greater hospitalizations for ambulatory care-sensitive conditions. This study provides further evidence that persons with spina bifida have hospitalizations that are beyond what the general population experiences. These conditions may be potentially preventable with appropriate ambulatory care. This group also had a greater risk for readmission within 30 days of discharge from their last hospitalization. More research is needed on the efficacy of programs aimed at prevention of these conditions.

Effects of folic acid fortification on spina bifida prevalence in Brazil

To assess spina bifida birth prevalence changes after folic acid fortification of wheat and maize flours began in Brazil in June 2004. Cross-sectional study of Brazilian live births in 2004 and 2006. Spina bifida birth prevalence from the Live Births Information System (SINASC: Sistema de Informações sobre Nascidos Vivos) in a prefortified period was compared to a period fortified with folic acid in each state. Observed prevalence rates in 2004 were used to calculate the expected prevalence rates in 2006 under the null hypothesis that both were similar. The observed/expected (O/E) ratios were tested by two-tailed Z-test. To minimize ascertainment differences among states, the O/E ratio of each one of the 27 Brazilian states was adjusted for the number of births with the Mantel-Haenszel statistic. RESULTS The reduction in spina bifida birth prevalence in 2006 was 39% (O/E = 0.61; 95% confidence interval [CI], 0.55-0.67), and 40% (O/E = 0.60; 95% CI, 0.53-0.68), after adjusting for state birth number. This reduction was significant (p < 0.0001), and heterogeneous among states (χ(2) = 72.96; p < 0.0001). Using SINASC data, there was a significant reduction in spina bifida birth prevalence in Brazil, probably related to the folic acid food fortification program.

Not Just for Workers: Maternal Exposure to Ambient Benzene Linked to Spina Bifida in Infants

Vol. 119, No. 3 NewsOpen AccessNot Just for Workers: Maternal Exposure to Ambient Benzene Linked to Spina Bifida in Infants Julia R. BarrettMS, ELS Julia R. Barrett Search for more papers by this author Published:1 March 2011https://doi.org/10.1289/ehp.119-a133aAboutSectionsPDF ToolsDownload CitationsTrack Citations ShareShare onFacebookTwitterLinked InRedditEmail Occupational exposure to hazardous air pollutants such as benzene has been linked in some studies to neural tube defects (NTDs), yet to date no one had studied whether exposure to ambient levels of benzene may similarly lead to adverse outcomes. A new study now reveals a positive association between exposure to ambient benzene in outdoor air and increased prevalence of spina bifida [EHP119(3):397–402; Lupo et al.].NTDs are a common type of birth defect. They arise when the neural tube fails to close during fetal development, leading to spina bifida (incomplete spinal column formation) or anencephaly (incomplete brain and skull formation). Both genetic and environmental factors, particularly inadequate folic acid intake, appear to play a role in NTDs.The Texas Birth Defects Registry provided data from 1 January 1999 to 31 December 2004 on 1,108 newborn infants, stillborn infants, and electively terminated fetuses with NTDs. A random set of 4,132 unaffected infants born during the same period served as a control group. Ambient air levels of benzene, toluene, ethylbenzene, and xylene were estimated at the census-tract level using the U.S. Environmental Protection Agency’s 1999 Assessment System for Population Exposure Nationwide (ASPEN) paired with mothers’ residential addresses at the time they gave birth. After exclusions for missing data and known chromosomal abnormalities or syndromes, 533 spina bifida cases, 303 anencephaly cases, and 3,695 control cases remained for analysis.Mothers with the highest estimated benzene exposure (≥3 μg/m3 in ambient air) were 2.3 times as likely as mothers in the reference group to bear children with spina bifida. The relationship between benzene exposure and spina bifida was statistically significant for most levels of exposure above the reference value, but the dose–response relationship was not monotonic (that is, the odds of risk did not increase consistently with each increase in exposure level). Associations between other solvents and spina bifida and between individual solvents and anencephaly also were observed but were not statistically significant.The study has several potential limitations including possible exposure misclassification, the availability of pollutant data for only 1 year of the study period, and limited information on potential confounders, such as maternal folic acid intake. However, these limitations are at least partially offset by ASPEN’s high-quality exposure estimates, the likelihood that pollutant levels were stable during the study years, and mandatory folic acid fortification of foods.This study is the first to suggest spina bifida prevalence is associated with maternal exposure to ambient air benzene levels. Further study of exposure, genotypes, and maternal nutrient status are needed to confirm this finding.FiguresReferencesRelatedDetails Vol. 119, No. 3 March 2011Metrics About Article Metrics Publication History Originally published1 March 2011Published in print1 March 2011 Financial disclosures License information EHP is an open-access journal published with support from the National Institute of Environmental Health Sciences, National Institutes of Health. All content is public domain unless otherwise noted. Note to readers with disabilities EHP strives to ensure that all journal content is accessible to all readers. However, some figures and Supplemental Material published in EHP articles may not conform to 508 standards due to the complexity of the information being presented. If you need assistance accessing journal content, please contact [email protected]. Our staff will work with you to assess and meet your accessibility needs within 3 working days.

Seasonality of spina bifida in Northern Germany

To verify a seasonal variation in the incidence of spina bifida and thus to identify possible environmental triggers leading to its developement. An interdisciplinary approach has been taken to develop a better understanding of spina bifida through collaborative efforts from investigators specializing in genetics, fetal pathology, paediatrics, neuro-surgery and prenatal ultrasonographic diagnosis. All pregnancies with fetal spina bifida were retrospectively analyzed from May 1 1993 through May 1 2010 at Luebeck University Fetal Health Center. Results were used to construct a model to predict the occurrence of fetal spina bifida based on seasonal variation and environmental influence reflected by climatic changes and environmental pollution. Furthermore, data were categorized in respect to the date of conception and subdivided into date of conception during summer (April-September) and winter months (October-March). Neither a seasonal distribution of conception for fetuses with spina bifida in the defined time frame could be verified nor a relevant influence of the analyzed environmental factors on the prevalence of spina bifida could be proved. The incidence of spina bifida has remained relatively stable within the last 17 years at 2.5 per 1,000 screened pregnancies. Since we were unable to demonstrate a relationship between seasonal variation and certain environmental factors on the incidence of fetal spina bifida, other factors should be investigated for a possible association with the onset of fetal spina bifida.

Prevalence of Spina Bifida Among Children and Adolescents in 10 Regions in the United States

The goal was to estimate the number of children and adolescents, 0 to 19 years of age, living with spina bifida (SB) in the United States. A retrospective study was conducted by using population-based, birth defect surveillance data from 10 US regions, with vital status ascertainment. Birth defect surveillance data were obtained from Arkansas, Georgia (5 central counties of metropolitan Atlanta), California (11 counties), Colorado, Iowa, New York (New York City excluded), North Carolina, Oklahoma, Texas, and Utah. We estimated the numbers of children 0 to 19 years of age who were living with SB in the 10 US regions in 2002, according to age group, race/ethnicity, and gender, and examined a long-term trend in the prevalence of SB among children 0 to 11 years of age in 1991-2002. The overall prevalence of SB among children and adolescents 0 to 19 years of age in the study regions was 3.1 cases per 10,000 in 2002. The prevalence of SB among children was lower among male and non-Hispanic black children. The prevalence estimates of SB among children and adolescents varied according to region, race/ethnicity, and gender, which suggests possible variations in prevalence at birth and/or inequities in survival rates. Additional studies are warranted to elucidate the reasons for these variations and to derive prevalence estimates of SB among adults.

Evaluación de la frecuencia de espina bífida oculta y su posible relación con el arsénico ambiental en una muestra prehispánica de la Quebrada de Camarones, norte de Chile

The Camarones River Valley, located in the extreme north of Chile, is characterized by high environmental arsenic levels and an arid desert. It has been inhabited by humans for the past 7,000 years. Evidence exists for chronic arsenic poisoning in both prehispanic and present populations residing in the area. Chronic arsenic exposure causes multi-systemic problems and can induce congenital malformations, in particular neural tube development defects such as spina bifida.To study the prevalence of spina bifida among prehispanic mummies of the area.One hundred and twenty prehistoric adult individuals were analyzed for evidence of spina bifda occulta of the sacrum in skeletal samples from the sites of Camarones 8, Camarones 9, Azapa 140 and Lluta 54, held in repository at the Museo Universidad de Tarapacá de Arica- San Miguel de Azapa. A diagnosis was considered positive when at least S1, S2 or S3 were affected. As controls, mummies of individuals that resided in Lluta and Azapa valley, with a low arsenic exposure, were analyzed.The frequency of spina bifida occulta among samples from the Camarones coast and Lluta and Azapa Valley were 13.5 and 2.4% respectively.Considering these were contemporaneous samples, and are believed to have had no other differences in diet or other factors, the differential exposures to arsenic could have produced the observed differences in spina bifida frequencies.