Birth region, race and sex may affect the prevalence of congenital diaphragmatic hernia, abdominal wall and neural tube defects among US newborns

Abstract

Birth defects are number one cause of death among infants below 1 year of age. The objective is to examine the interaction of sex, race/ethnicity and place of birth on the prevalence of major congenital birth anomalies. We analyzed the data sets produced by the Healthcare Cost and Utilization Project (HCUP) for the years 1997-2004. We identified the malformations: congenital diaphragmatic hernia (CDH), abdominal wall defects (AWD) and neural tube defects (NTD) using their respective International Classification of Disease 9 diagnostic codes. Newborns were classified according to their birth region into four groups; Northeast, South, Midwest and West. We calculated prevalence of each disease for the overall sample then for every sex, race and birth region. Using stratified analysis and χ(2) test, we calculated the odds ratio (OR) risk for each disease comparing females with males, different races/ethnicity to Caucasians and different US regions to Northeast. There were 1291 newborns with CDH representing 0.031% of the sample. (AWD: 2184 (0.052%) and NTD: 979 (0.024%)). West region had the highest prevalence of CDH (OR=1.62 (confidence intervals (CI): 1.4-1.9, P<0.001)). Female-to-male risk disparities were most observed among Caucasians in the South (OR=1.44 (CI: 1.1-1.8, P=0.003)). African Americans had the least prevalence of CDH but only in the South (OR=0.67 (CI: 0.5-0.8, P=0.001)). Native Americans had higher risk for AWD in the Midwest and West regions compared with Caucasians. This study links the birth region as a detrimental factor like sex and race in the prevalence of CDH, AWD and NTD. These findings implicate a possible role for environmental factors in the pathogenesis of these diseases.