The use of the computerized and revised vital record in conducting etiologic studies on neural tube defects

The purpose of this study was to evaluate the adequacy of computerized vital records in Texas for conducting etiologic studies on neural tube defects (NTDs), using the revised and expanded National Centers for Health Statistics vital record forms introduced in Texas in 1989.^ Cases of NTDs (anencephaly and spina bifida) among Harris County (Houston) residents were identified from the computerized birth and death records for 1989-1991. The validity of the system was then measured against cases ascertained independently through medical records and death certificates. The computerized system performed poorly in its identification of NTDs, particularly for anencephaly, where the false positive rate was 80% with little or no improvement over the 3-year period. For both NTDs the sensitivity and predictive value positive of the tapes were somewhat higher for Hispanic than non-Hispanic mothers.^ Case control studies were conducted utilizing the tape set and the independently verified data set, using controls selected from the live birth tapes. Findings varied widely between the data sets. For example, the anencephaly odds ratio for Hispanic mothers (vs. non-Hispanic) was 1.91 (CI = 1.38-2.65) for the tape file, but 3.18 (CI = 1.81-5.58) for verified records. The odds ratio for diabetes was elevated for the tape set (OR = 3.33, CI = 1.67-6.66) but not for verified cases (OR = 1.09, CI = 0.24-4.96), among whom few mothers were diabetic. It was concluded that computerized tapes should not be solely relied on for NTD studies.^ Using the verified cases, Hispanic mother was associated with spina bifida, and Hispanic mother, teen mother, and previous pregnancy terminations were associated with anencephaly. Mother's birthplace, education, parity, and diabetes were not significant for either NTD.^ Stratified analyses revealed several notable examples of statistical interaction. For anencephaly, strong interaction was observed between Hispanic origin and trimester of first prenatal care.^ The prevalence was 3.8 per 10,000 live births for anencephaly and 2.0 for spina bifida (5.8 per 10,000 births for the combined categories). ^

A geographic information science (GIS) approach to conducting comparative area-level community assessments in the Texas CORD Study

This study assessed and compared sociodemographic and income characteristics along with food and physical activity assets (i.e. grocery stores, fast food restaurants, and park areas) in the Texas Childhood Obesity Research Demonstration (CORD) Study intervention and comparison catchment areas in Houston and Austin, Texas. The Texas CORD Study used a quasi-experimental study design, so it is necessary to establish the interval validity of the study characteristics by confirming that the intervention and comparison catchment areas are statistically comparable. In this ecological study, ArcGIS and Esri Business Analyst were used to spatially relate U.S. Census Bureau and other business listing data to the specific school attendance zones within the catchment areas. T-tests were used to compare percentages of sociodemographic and income characteristics and densities of food and physical activity assets between the intervention and comparison catchment areas.^ Only five variables were found to have significant differences between the intervention and comparison catchment areas: Age groups 0-4 and 35-64, the percentage of owner-occupied and renter-occupied households, and the percentage of Asian and Pacific Islander residents. All other variables showed no significant differences between the two groups. This study shows that the methodology used to select intervention and comparison catchment areas for the Texas CORD Study was effective and can be used in future studies. The results of this study can be used in future Texas CORD studies to confirm the comparability of the intervention and comparison catchment areas. In addition, this study demonstrates a methodology for describing detailed characteristics about a geographic area that practitioners, researchers, and educators can use.^