Occurrence of Conotruncal Heart Birth Defects in Texas: A Comparison of Urban/Rural Classifications

Authors


  • This study was supported in part through cooperative agreement U50/CCU613232 from the Centers for Disease Control and Prevention. The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the Centers for Disease Control and Prevention. The authors would also like to thank the staff of the Birth Defects Epidemiology and Surveillance Branch, Texas Department of State Health Services, for their hard work in collecting these data and travelling to sometimes distant rural hospitals to do so. For further information, contact: Peter H. Langlois, PhD, Birth Defects Epidemiology and Surveillance Branch, Texas Department of State Health Services, Mail Code 1964, PO Box 149347, Austin, TX 78714-9347; e-mail peter.langlois@dshs.state.tx.us.

Abstract

Purpose: (1) Determine if there is an association between 3 conotruncal heart birth defects and urban/rural residence of mother. (2) Compare results using different methods of measuring urban/rural status.

Methods: Data were taken from the Texas Birth Defects Registry, 1999-2003. Poisson regression was used to compare crude and adjusted birth prevalence.

Findings: Based on residences of births in Texas, the values for urban influence code (UIC), rural urban continuum code (RUCC), and rural urban commuting area (RUCA) were highly correlated with each other and, less highly, to percentage of land in crops. For tetralogy of Fallot, the most rural category consistently showed the highest prevalence ratio for all measures. The adjusted prevalence ratio for highest percentage cropland was 1.73 [95% CI, 1.14-2.51] using natural breaks and 1.42 [95% CI, 1.07-1.86] using quartiles. The trend with cropland percentage was significant (P < .03), whether crude or adjusted. The crude trend was also significant using RUCC. Neither truncus arteriosus nor transposition of the great arteries exhibited consistent associations with urban or rural residence.

Conclusions: The urban/rural measures were generally correlated with each other; as a broad measure, RUCA has advantages for many health studies. Tetralogy of Fallot was most prevalent in rural areas; that pattern was strongest using percentage of land in crops.

Ancillary