|Unique conditions exists along the Lower Rio Grande Valley, and birth defect rates have often been high in these communities.
The 1991 Cluster
In April 1991, three babies with anencephaly were born in a Brownsville, Texas, hospital within 36 hours. The three babies died soon after birth. Since this was an unusual cluster, it got the notice of the health workers in the area. Doctors in the Texas State Department of State Health Services (DSHS) asked epidemiologists from the Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia, to help them look into the problem.
In response to this cluster and the need for better data, and in recognition of the enormous resources routinely put forth by DSHS in the investigation of birth defect clusters, the Texas State Legislature passed the Texas Birth Defects Act in 1993. Out of this statute, the Texas Birth Defects Registry was created to actively identify children born with birth defects. At about the same time, the Texas Neural Tube Defects Project (TNTDP) was initiated by DSHS and collaborators. This seven-year study, funded in large part by the CDC, focused on surveillance, research and recurrence prevention in Texas counties along the border with Mexico. Although the TNTDP wrapped up data collection in 2000, scientific research into the possible causes of NTDs continues to be published by the Texas Department of State Health Services.
About the Border
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Health disparities between Texans living along the border with Mexico and those living in non-border areas have long been a concern for public health officials, as well as for those who live and work in the border counties. Brownsville, the most southern city in Texas, is in Cameron County on the Mexico border. In 1989, over 80% of the people were Hispanic and over 40% of the families had low incomes. In 1990, 270,524 people lived in Cameron County.
When these cases occurred in Cameron County in 1991, little was known about what causes NTDs like anencephaly. It was known that, in the United States, NTDs are most common among Hispanics and least common in African Americans. The birth defects are also more common in families with low incomes. Community members thought the birth defect problems could be related to pollution from pesticide use and assembly plant industries along the Mexico/U.S. border.
What's Being Done
Since 1997, the Texas Birth Defects Epidemiology and Surveillance staff has contributed information about birth defects cases as well as from healthy “control” families in border counties to the National Birth Defects Prevention Study. The study area for Texas is currently the area known as the Lower Rio Grande Valley, which encompasses Gulf Coast industrial cities such as Corpus Christi, as well as Cameron County.
In addition, several cluster investigations have been done in an effort to remain alert to possible spikes in the rates of NTDs along the border.
Finally, several public education campaigns and clinic-based programs have focused on encouraging women of childbearing age to take folic acid daily, a practice which could prevent 50-75% of all cases of NTDs.