Agricultural contamination of groundwater as a possible risk factor for growth restriction or prematurity.

Agricultural activity on Prince Edward Island poses a potential hazard to groundwater, which is the sole source of drinking water on the island. This study investigates the potential impact of groundwater nitrate exposure on prematurity and intrauterine growth restriction on Prince Edward Island. A total of 210 intrauterine growth restriction cases, 336 premature births, and 4098 controls were abstracted from a database of all Island births. An ecological measure of groundwater nitrate level was used to gauge potential exposure to agriculturally contaminated drinking water. The higher nitrate exposure categories were positively associated with intrauterine growth restriction and prematurity, and significant dose-response trends were seen, even after adjustment for several important covariates. Nevertheless, these risks must be interpreted cautiously because of the ecological nature of this exposure metric. An investigation using nitrate levels for individual study subjects is needed to confirm this association.