Application of the automated spatial surveillance program to birth defects surveillance data

BACKGROUND: Although many birth defects surveillance programs incorporate georeferenced records into their databases, practical methods for routine spatial surveillance are lacking. We present a macroprogram written for the software package R designed for routine exploratory spatial analysis of birth defects data, the Automated Spatial Surveillance Program (ASSP), and present an application of this program using spina bifida prevalence data for metropolitan Atlanta. METHODS: Birth defects surveillance data were collected by the Metropolitan Atlanta Congenital Defects Program. We generated ASSP maps for two groups of years that correspond roughly to the periods before (1994-1998) and after (1999-2002) folic acid fortification of flour. ASSP maps display census tract-specific spina bifida prevalence, smoothed prevalence contours, and locations of statistically elevated prevalence. We used these maps to identify areas of elevated prevalence for spina bifida. RESULTS: We identified a large area of potential concern in the years following fortification of grains and cereals with folic acid. This area overlapped census tracts containing large numbers of Hispanic residents. CONCLUSIONS: The potential utility of ASSP for spatial disease monitoring was demonstrated by the identification of areas of high prevalence of spina bifida and may warrant further study and monitoring. We intend to further develop ASSP so that it becomes practical for routine spatial monitoring of birth defects.     

Integration of DNA sample collection into a multi-site birth defects case-control study

BACKGROUND: Advances in quantitative analysis and molecular genotyping have provided unprecedented opportunities to add biological sampling and genetic information to epidemiologic studies. The purpose of this article is to describe the incorporation of DNA sample collection into the National Birth Defects Prevention Study (NBDPS), an ongoing case-control study in an eight-state consortium with a primary goal to identify risk factors for birth defects. METHODS: Babies with birth defects are identified through birth defects surveillance systems in the eight participating centers. Cases are infants with one or more of over 30 major birth defects. Controls are infants without defects from the same geographic area. Epidemiologic information is collected through an hour-long interview with mothers of both cases and controls. We added the collection of buccal cytobrush DNA samples for case-infants, control-infants, and their parents to this study. RESULTS: We describe here the methods by which the samples have been collected and processed, establishment of a centralized resource for DNA banking, and quality control, database management, access, informed consent, and confidentiality issues. CONCLUSIONS: Biological sampling and genetic analyses are important components to epidemiologic studies of birth defects aimed at identifying risk factors. The DNA specimens collected in this study can be used for detection of mutations, study of polymorphic variants that confer differential susceptibility to teratogens, and examination of interactions among genetic risk factors. Information on the methods used and issues faced by the NBDPS may be of value to others considering the addition of DNA sampling to epidemiologic studies.     

基于GIS的中国土地生产潜力研究

在地理信息系统（ＧＩＳ）及全国农业空间数据库和属性数据库的支持下,在前人关于农业生产潜力研究的基础上,进行了全国土地生产潜力的研究。首先探讨了基于ＧＩＳ的土地生产潜力研究方法;然后,就土地生产潜力的“土壤有效系数”进行重点研究,探讨了其计算方法与模型;并应用机制法,通过光、温、水、土逐级衰减,具体计算了全国分县土地生产潜力;最后,通过分析统计和分析制图,分析了中国土地生产潜力的数值分布和空间分布特     

Clinician reviewers in birth defects surveillance programs: survey of the National Birth Defects Prevention Network

BACKGROUND: Some birth defects surveillance programs utilize a clinician reviewer ("Clinician") to assist the multidisciplinary staff in the process of case review, coding and classification. The untested assumption is that expertise in the evaluation of individuals with birth defects and genetic syndromes in clinical practice, usually clinical genetics, is useful in reviewing medical records. METHODS: We conducted an exploratory survey of the 50 functioning birth defects surveillance programs that participated in the National Birth Defects Prevention Network in 2004. The survey was mailed electronically to program coordinators and included 10 questions with check-off option replies. Open-ended comments were also solicited. RESULTS: Responses were received from 31 of 50 (62%) programs, 21 (68%) which used a Clinician. In addition to the 9 centers that identified themselves as participants in the National Birth Defects Prevention Study (NBDPS), there were 12 non-NBDPS programs using a Clinician, 2 of whom were not clinical geneticists (1 nurse genetic counselor and 1 primary pediatrician). A total of 86% (18/21) of Clinicians were employed part-time or as consultants; 1 was full-time, and 2 were volunteers. In addition to the core activities of classifying defects and reviewing cases to determine if a syndrome was present, over one-half of the Clinicians participated in education of birth defects surveillance programs staff, research, and program development. Most (86%; 18/21) Clinicians had been trained informally for their roles. Only 1 had received a formal performance review. CONCLUSIONS: Aside from the 9 centers in the NBDPS in which the position of Clinician is funded by the Centers for Disease Control and Prevention (CDC), about one-half of the remaining respondent birth defects surveillance programs used a Clinician. Future research is needed to determine why a birth defects surveillance program hires or refrains from using a Clinician, and whether a Clinician accomplishes the desired goals. This survey reveals a lack of formal training for the Clinicians in their roles in the surveillance programs, and a lack of quality monitors, which might be addressed in the future.     

Spatial Epidemiology and GIS in Marine Mammal Conservation Medicine and Disease Research

The use of spatial epidemiology and geographical information systems (GIS) facilitates the incorporation of spatial relationships into epidemiological investigations of marine mammal diseases and conservation medicine. Spatial epidemiology is the study of the spatial variation in disease risk or incidence and explicitly addresses spatial structures and functions that factor into disease. The GIS consists of input, management, analysis, and presentation of spatial disease data and can act as an integrative tool so that a range of varied data sources can be combined to describe different environmental aspects of wild animals and their diseases. The use of modern spatial analyses and GIS is becoming well developed in the field of marine mammal ecology and biology, but has just recently started to gain more use in disease research. The use of GIS methodology and spatial analysis in nondisease marine mammal studies is briefly discussed, while examples of the specific uses of these tools in mapping, surveillance and monitoring, disease cluster detection, identification of environmental predictors of disease in wildlife populations, risk assessment, and modeling of diseases, is presented. Marine mammal disease investigations present challenges, such as less consistent access to animals for sampling, fewer baseline data on diseases in wild populations, and less robust epidemiologic study designs, but several recommendations for future research are suggested. Since location is an integral part of investigating disease, spatial epidemiology and GIS should be incorporated as a data management and analysis tool in the study of marine mammal diseases and conservation medicine.     

Application of GIS in epizootiological surveillance of swine trichinellosis in one endemic district in Serbia

Application of new tools for epizootiological investigations in veterinary medicine, such as Geographical Information Systems (GIS), offers a new approach and possibilities for the eradication or control of infectious diseases. GIS is particularly useful for research conducted in small areas strongly impacted by man. Trichinellosis is a world-wide zoonosis, which is endemic in some European countries, Balkan district and Serbia in particular. There are very few data on GIS application in the field of trichinellosis. We here present the application of GIS for mapping Trichinella spp. occurrence and spatial and temporal patterns of Trichinello infection in one endemic district in Serbia. Settlements with trichinellosis were marked and particular points of interest were designated. Data on prevalence of Trichinella infection in domestic swine accompanied by location of foci indicated the existence of disease geographical stationarity. This first report on GIS application in Serbia will facilitate trichinellosis surveillance and monitoring of Trichinella spp. circulation among domestic pigs, and populations of synanthropic and sylvatic animals.     

Visualization and interpretation of birth defects data using linked micromap plots

BACKGROUND: Many states have implemented birth defects surveillance systems to monitor and disseminate information regarding birth defects. However, many of these states rely on tabular methods to disseminate statistical birth defects summaries. An innovative presentation technique for birth defect data that portrays the information in a joint geographical and statistical context is the linked micromap (LM) plot. METHODS: LM plots were generated for oral cleft data at two geographical resolutions—USA states and counties of Utah. The LM plots also included demographic and behavioral risk data. RESULTS: A LM plot for the USA reveals spatial patterns indicating higher oral cleft occurrence in the southwest and the midwest and lower occurrence in the east. The LM plot also indicates relationships between oral cleft occurrence and maternal smoking rates and the proportion of American Indians and Alaskan Natives. In particular, the five states with the highest oral cleft occurrence had a higher proportion of American Indians and Alaskan Natives. Among the 15 states with the highest oral cleft occurrence, nine had a smoking rate of 16% or higher while among the 15 states with the lowest oral cleft occurrence only one state had a smoking rate greater than 16%. The LM plot for the state of Utah shows no clear geographic pattern, due perhaps to a relatively small number of cases in a limited geographic area. CONCLUSIONS: LM plots are effective in representing complex and large volume birth defects data. Integration to birth defects surveillance systems will improve both presentation and interpretation. Birth Defects Research (Part A), 2008. © 2007 Wiley‐Liss, Inc.     

Spatial and temporal modelling for parasite transmission studies and risk assessment

Spatial and temporal modelling of parasite transmission and risk assessment require relevant spatial information at appropriate spatial and temporal scales. There is now a large literature that demonstrates the utility of satellite remote sensing and spatial modelling within geographical information systems (GIS) and firmly establishes these technologies as the key tools for spatial epidemiology. This review outlines the strength of satellite remotely sensed data for spatial mapping of landscape characteristics in relation to disease reservoirs, host distributions and human disease. It is suggested that current satellite technology can fulfill the spatial mapping needs of disease transmission and risk modelling, but that temporal resolution, which is a function of the satellite data acquisition characteristics, may be a limitating factor for applications requiring information about landscape or ecosystem dynamics. The potential of the Modis sensor for spatial epidemiology is illustrated with reference to mapping spatial and temporal vegetation dynamics and small mammal parasite hosts on the Tibetan plateau. Future research directions and priorities for landscape epidemiology are considered.     

Malaria elimination: moving forward with spatial decision support systems

Operational challenges facing contemporary malaria elimination have distinct geospatial elements including the need for high-resolution location-based surveillance, targeted prevention and response interventions, and effective delivery of essential services at optimum levels of coverage. Although mapping and geographical reconnaissance (GR) has traditionally played an important role in supporting malaria control and eradication, its full potential as an applied health systems tool has not yet been fully realised. As accessibility to global positioning system (GPS), geographic information system (GIS) and mobile computing technology increases, the role of an integrated spatial decision support system (SDSS) framework for supporting the increased operational demands of malaria elimination requires further exploration, validation and application; particularly in the context of resource-poor settings.     

Geographical Information System (GIS) as a Tool in Surveillance and Monitoring of Animal Diseases

In the veterinary epidemiology, the advantage of mapping the locations of farms and other facilities with animals is obvious. In an outbreak of a disease it could make the management of the situation easier, and it could also provide a tool to evaluate different strategies to prevent the spread of infectious diseases. This paper aims to describe and give an overview of the possibilities and potential uses of a Geographical Information System (GIS) in the field of surveillance and monitoring of animal diseases. The following areas in which GIS and special GIS-functions could be incorporated are presented: recording and reporting information, epidemic emergency, cluster analysis, modelling disease spread, and planning control strategies. Different sources of data; geographical data, farm locations and disease information, used in the development of the GIS at the National Veterinary Institute in Norway are thoroughly described in the paper. Further, it presents a few examples where the GIS has been applied to studies of epidemiology and surveillance of animal diseases in Norway, which shows the significant value of GIS in these areas. At the same time, the incorporation of GIS in this field shows the scarcity of the data available, which should encourage improvement in the data recording and the quality of the registries.     

Improving case ascertainment of a population-based birth defects registry in New York State using hospital discharge data

BACKGROUND: The assessment of the data quality of population-based registration systems is essential to understanding the reliability and usefulness of disease surveillance and research findings resulting from the use of registry data. Since the New York State Congenital Malformations Registry (CMR) uses passive case ascertainment, the completeness of the registry data is an important aspect of the quality of information. This paper presents the results of hospital audits, which were conducted to capture the unreported cases using hospital discharge files, and evaluates the effectiveness of the audits. METHODS: Children age 2 years or younger and diagnosed with reportable birth defects for the birth years 1998-2000 were selected from hospital discharge files of all reporting hospitals in the New York Statewide Planning and Research Cooperative System (SPARCS) and matched to the CMR database for the same birth year period.The unmatched reports from the SPARCS hospital discharge files that the CMR possibly missed were sent to hospitals, requesting submission of the missed reports. Two audits on all reporting hospitals in New York State were conducted: 1) 1998 and 1999 birth cohorts audited from June 2000 to March 2002, and 2) 2000 birth cohort audited from November 2001 to November 2002. RESULTS: Hospital audits using SPARCS hospital discharge data identified 5,460 reports that the CMR missed for the selected 66 hospitals analyzed. About 86% of these reports had reportable conditions and were added to the CMR, which comprised 21.4% of all reports from the 66 hospitals for the birth years 1998-2000. The number of reports that would have been missed without audits decreased from the 1998 and 1999 birth cohort (25.1%) to the 2000 birth cohort (13.9%). Low reporting rates and, thus, a high percent of added reports, were found for hospitals with a relatively small number of annual reports and for some specific birth defects such as chromosomal anomalies, anencephalus and congenital anomalies of the urinary system. CONCLUSION: The current study demonstrates that using hospital discharge data to improve case ascertainment is a valuable and effective method of enhancing birth defect surveillance, particularly for those hospitals with low reporting rates.     

Improving the quality of surveillance data on congenital heart defects in the metropolitan Atlanta congenital defects program

BACKGROUND: One of the challenges in epidemiologic studies of congenital heart defects (CHDs) has been the lack of a current, standard nomenclature and classification system. Recently such a standard nomenclature became available from the Society of Thoracic Surgeons (STS) Congenital Heart Surgery Database. This study reports the classification of cases of CHDs in a birth defects surveillance database using modified STS nomenclature. METHODS: Records of infants and fetuses in the Metropolitan Atlanta Congenital Defects Program delivered during 1968-2003 with CHD diagnoses were reviewed by a team of pediatric cardiologists. The cases were assigned one or more STS codes and subsequently grouped into successively broader levels of aggregation. Aggregation was based on presumed morphogenetically similar developmental mechanisms. RESULTS: There were 12,639 cases reviewed, of which 89% had a single, primary STS code. Structural CHDs were found in 7,749 infants, while 4,890 were considered to have structurally normal hearts. Application of clinical CHD nomenclature improved the clinical accuracy of surveillance data by eliminating normal physiologic variants and obligatory shunt lesions. Classification also aggregated specific CHDs into groups appropriate for research and surveillance. CONCLUSIONS: Application of a current, standard CHD nomenclature and classification system to cases in a birth defects surveillance database improves the specificity of cardiac diagnoses and allows for the development of a flexible case aggregation system for monitoring of CHD prevalence.     

Trends of selected malformations in relation to folic acid recommendations and fortification: an international assessment

BACKGROUND: Two crucial issues relative to the benefits and impact of folic acid in the prevention of birth defects are whether supplementation recommendations alone, without fortification, are effective in reducing the population-wide rates of neural tube defects (NTDs), and whether such policies can reduce the occurrence of other birth defects. Using data from 15 registries, we assessed rates and trends of 14 major defects, including NTDs, in areas with official recommendations or fortification to assess the effectiveness of recommendations and fortification on a wide range of major birth defects. METHODS: We evaluated surveillance data through 2003 on major birth defects from population-based registries from Europe, North America, and Australia. All included ascertainment of pregnancy terminations (where legal). Trends before and after policies or fortification were assessed via Poisson regression and were compared via rate ratios. RESULTS: Significant changes in trends were seen for NTDs in areas with fortification but not in areas with supplementation recommendations alone. For other major birth defects, there was an overall lack of major trend changes after recommendations or fortification. However, some significant declines were observed for select birth defects in individual areas. CONCLUSIONS: Recommendations alone remain an ineffective approach in translating the known protective effect of folic acid in population-wide decline in NTD rates. Fortification appears to be effective in reducing NTDs. The effect on other birth defects remains unclear.     

基于GIS的产业生态学研究述评

产业生态学由于缺少关于空间分析的工具,使得研究结果因缺乏空间维度信息而影响对管理效率和精准度的支持。基于GIS的产业生态学相关研究已成为产业生态学研究的一个新的方向。为总结已有的研究成果并展望未来的研究方向,运用文献计量及对比分析的手段,系统分析了国内外基于GIS的产业生态学的相关研究进展,得出以下结论:当前基于GIS的产业生态研究主要集中在物质代谢、产业共生和生命周期评价3个方面,将GIS技术引入到物质代谢研究中,可以更好的展示物质代谢的时空分布格局,为物质代谢研究提供了一种新的方法;基于GIS技术,不仅可以更加高效地挖掘潜在的产业共生机会,还可应用于生态产业园的规划管理如企业的选址、空间布局等以及废弃物的回收再利用方面;将GIS与LCA耦合在一起,可以很好地补充、完善和管理传统数据,有助于探索产品、活动或工艺的环境影响的空间特性以及进行土地利用相关的环境影响评价。另外,国内外研究的侧重点也不尽相同。在物质代谢研究中,国内研究较少,仅在城市尺度上进行了基础设施的物质代谢及其存量分析,国外在国家、城市尺度上研究了铜、锌等金属的物质代谢情况;在产业共生研究中,国内侧重于生态产业园的研究,而国外侧重于城市尺度的产业共生机会识别的研究;在LCA的研究中,国内开展了基于GIS的生命周期评价数据库和产品材料信息管理系统的研究,而国外侧重于进行区域化的生命周期评价、进行土地利用影响类型的相关评价以及污染物的追踪,国内在该方面尚处于起步阶段。国内外在研究方法上存在共性,都是基于GIS的空间分析方法、缓冲区分析方法以及数据库技术等。未来将GIS作为一个平台,面向产业转型展开产业生态学综合理论方法的研究,可以为产业的可持续性管理提供有效支持。     

Changes in the birth prevalence of selected birth defects after grain fortification with folic acid in the United States: findings from a multi-state population-based study

BACKGROUND: Observational studies and clinical trials have suggested that periconceptional use of folic acid can reduce the risk of birth defects other than neural tube defects (NTDs). Using data reported by states to the National Birth Defects Prevention Network, we examined whether folic acid fortification might have decreased the prevalence of other specific birth defects. METHODS: For each of 16 birth defect categories selected for study, birth prevalence for two time periods was calculated with data submitted from a number of states in 1995-1996 ("pre-fortification") and 1999-2000 ("post-fortification"). Changes in birth prevalence between the two time periods were assessed by calculating prevalence ratios and 95% confidence intervals for each defect, and compared by maternal race/ethnicity and availability of prenatally diagnosed cases. RESULTS: We confirmed previously reported reductions in the birth prevalence of NTDs. In addition, we found modest, yet statistically significant, decreases in the birth prevalence for transposition of the great arteries(12%), cleft palate only (12%), pyloric stenosis (5%), upper limb reduction defects (11%), and omphalocele (21%). More substantial subgroup decreases were observed for renal agenesis among programs that conduct prenatal surveillance (28%), for common truncus among Hispanics (45%), and for upper limb reduction defects among Hispanics (44%). There were modest yet significant increases in the prevalence of obstructive genitourinary defects (12%) and Down syndrome (7%), but not among programs conducting prenatal surveillance for these defects. CONCLUSIONS: These results suggest some modest benefit from the folic acid fortification on the prevalence of a number of non-NTD birth defects.     

Case fatality among infants with congenital malformations by lethality

OBJECTIVE: Infant mortality rates continue to show that congenital anomalies are the leading cause of infant death in the United States. However, studies of factors contributing to increased mortality across different types of congenital anomalies have been limited. The objective of this study was to assess whether the likelihood of infant mortality varied by maternal race and ethnic group while considering the severity of the birth defect. METHODS: A retrospective cohort analysis was conducted using data from Colorado's statewide, population-based birth defects surveillance system (CRCSN). The cohort included infants, born between 1995 and 2000 to Colorado resident mothers, who were diagnosed with major congenital malformations stratified by degree of lethality. Multiple logistic regression was performed for each level of lethality, and included the following potential explanatory variables: maternal race/ethnicity, clinical gestation, birth weight, maternal education level, maternal age, and sex of child. RESULTS: Within the low/very low lethality cohort, maternal race/ethnicity of Black/non-Hispanic was associated with increased risk of infant mortality, OR 2.81 (1.41-5.19), as were low and very low birth weight, OR 2.21 (1.12-4.04) and 19.31 (11.84-31.01), respectively. Maternal race/ethnicity was not a significant risk factor in either high or very high lethality groups; however, the interaction between birth weight and gestational age significantly increased the risk of mortality. CONCLUSIONS: Through the use of statewide, population-based birth defects surveillance data, a disparity in infant mortality has been identified in a specific subset of the population that could be investigated further and targeted for prevention activities.     

Pregnancy outcomes following systemic prenatal acyclovir exposure: Conclusions from the international acyclovir pregnancy registry, 1984-1999

BACKGROUND: Oral acyclovir is commonly used for genital herpes and other herpesvirus infections. Data on potential fetal risk are extremely limited. From 1984 to 1998, the Acyclovir in Pregnancy Registry monitored birth outcomes of women exposed to oral or intravenous acyclovir during pregnancy. This report describes the final results. METHODS: The registry was publicized to health care providers most likely to diagnose pregnancy; providers called the registry telephone number, then mailed in a brief questionnaire. Pregnancy outcomes were categorized either as outcomes with birth defects or outcomes without birth defects, subcategorized as live births, spontaneous pregnancy losses (including stillbirths), and induced abortions. Birth defects were defined using a modification of the CDC definition for birth defects surveillance systems. Observed rates were compared to the rate (3.2%) of birth defects expected in the general population. RESULTS: Between June 1, 1984 and June 30, 1998, 1695 pregnancies exposed to oral or IV acyclovir were registered; 461 (27%) were lost to follow-up. A total of 1234 pregnancies in 24 countries were followed, with a total of 1246 outcomes. Among 1246 pregnancy outcomes, 756 involved acyclovir exposure in the first trimester, 197 in the second trimester, and 291 in the third trimester. Among live births with first trimester acyclovir exposure, risk of birth defects was 19 of 596 (3.2%; 95% CI, 2.0-5.0%). No unusual defects or pattern of defects were apparent. CONCLUSIONS: The observed rates and types of birth defects for pregnancies exposed to acyclovir did not differ significantly from those in the general population. Birth Defects Research (Part A), 2004. Published 2004 Wiley-Liss, Inc.