Incidence of abdominal wall defects is related to surface water atrazine and nitrate levels.

Background: Gastroschisis and omphalocele are congenital abdominal wall defects (AWD). Atrazine and nitrates are common agricultural fertilizers.

Methods: The Centers for Disease Control and Prevention natality data set was used to collect data for patients with AWD born between January 1990 and December 2002. Similar data were obtained from the Indiana State Department of Health. An estimated date of conception was calculated by birth date and gestational age. Surface water nitrate and atrazine levels for Indiana were collected from US Geological Survey data. Midwest was defined as Indiana, Illinois, Iowa, Ohio, and Nebraska. Statistical analysis was performed by chi2 test and Pearson correlation for P < or = .05.

Results: The Centers for Disease Control and Prevention identified 9871 children with AWD in 1990 and in 1995-2001 of 35,876,519 live births (rate 2.75/10(5)). In Indiana, 358 children from 1990-2001 had AWD of 1,013,286 live births (rate 3.53/10(5)). The AWD rate in Indiana was significantly higher than the national rate in 1996 (P = .0377), 1998 (P = .0005), and 2001 (P = .0365) and significantly higher than the Midwest rate in 1998 (P = .0104). Monthly comparison demonstrated a positive correlation of AWD rate and mean atrazine levels (P = .0125).

Conclusion: Indiana has significantly higher rates of AWD compared with national rates. Increased atrazine levels correlate with increased incidence of AWD.