SPATIAL DISTRIBUTION OF COARCTATION OF THE AORTA MAPS TO LAND USE AS CROPLAND

Abstract

Introduction Left heart obstructions [LHO] including coarctation of the aorta [CoAo], aortic stenosis [AS] and hypoplastic left heart [HLH] are thought to share genetic potential. Family history of congenital cardiovascular malformations [CCVM] is more common in the LHO group than in CCVM as a whole. Methods In using a case control series of congenital cardiovascular malformations and population-based controls, we analyzed spatial distribution of CoAo in infants diagnosed before one year of age. Statistical analysis included spatial distribution and extensive personal sociodemographic, occupational exposures, and life style exposure factors as well as family history of cardiac or other malformations. Cases and controls were mapped in the State of Maryland and the District of Columbia in the United States, including the years 1981 through 1989. Results 102 cases of coarctation of the aorta and 1990 controls were included in the analysis. Spatial scanning by Bernoulli method demonstrated five clusters of cases of CoAo containing a total of 33 cases. The largest cluster contains 20 cases and is significantly distributed compared to controls with #61539;229.5882, p. 000 and odds ratio of 3.9. For all cases of coarctation, clustered or not, case status is associated in a multiple regression model with family history of cardiac malformations, family history of other malformations, father's occupational or leisure exposure to solder; or mother's occupational or leisure exposure to solvents. When the largest cluster of CoAo cases is analyzed however, its characteristics are association with cropland, odds ratio 8.91, 95% confidence intervals 2.6 to 30.8, and with maternal exposure to solvents, odds ratio 12.9 with 95% confidence intervals .0.98 to 171.0. If all clusters are considered together, the combined area is associated with cropland with similar odds. If the region of the clustered coarctation cases is analyzed for association using the larger control population, the cluster is associated with orchards, cropland, and race. In analyses by racial groups, the association with cropland persists. The clusters of coarctation of the aorta are geographically distinct from clusters identified of aortic stenosis. Conclusion We conclude that clusters of coarctation of the aorta are present in population-based studies of Maryland and the District of Columbia. These clusters are characterized by land use as orchards or cropland. The largest cluster is in a region of the state where tobacco and soybeans are the primary crops in contrast to the regions of the state in which aortic stenosis is clustered where corn, soybeans and hay are grown. Possible exposure to environmental chemicals may be important to gene environment interactions that are causal for congenital cardiovascular malformations.