In the largest study done to date on birth defects among racial and ethnic groups, researchers found that some birth defects are more common in specific groups than others, especially American Indians and Alaska Natives when compared to other groups.
The study, conducted by the Centers for Disease Control and Prevention, is based on pooled data from 12 U.S.-population-based birth defects surveillance systems, which included 13.5 million live births. (This comprised one of three U.S. births.) The study was conducted from 1999 to 2007. There were 13 racial/ethnic groups studied as well as a group of non-Hispanic whites.
Among American Indians/Alaska Natives (non-Hispanic), the results were that they had substantially higher rates for:
- Anotia or microtia (ear defects)
- Cleft lip with or without cleft palate
- Trisomy 18 (a chromosomal defect that affects development)
- Encephalocele (serious defect of the skull and brain)
- Lower, upper, and any limb deficiency (part or all of a limb fails to form during pregnancy).
Cubans and Asians, especially Chinese and Asian Indians, had substantially lower or similar rates of those defects when compared with non-Hispanic Whites. The exceptions were anotia or microtia among Chinese and Filipino babies, and tetralogy of Fallot among Vietnamese babies. (Tetralogy of Fallot is a congenital heart defect.)
Other results were that non-Hispanic black babies had a greater risk of being born with encephalocele and trisomy 18. Hispanics were more likely to be born with anencephaly (where the baby is born without major parts of the brain), encephalocele, and anotia/microtia.
Conversely, the researchers looked at the birth defects that were less likely to occur in special racial and ethnic groups, and found there was a lowered rate of hypospadias (a deformity of the penis) in American Indians/Alaska Natives, Asians, and Hispanics. Non-Hispanic Asians and blacks were less likely to be born with the heart defect aortic valve stenosis.
“This is the largest population-based study to our knowledge to systematically examine the prevalence of a range of major birth defects across many racial/ethnic groups, including Asian and Hispanic subgroups,” the authors notes. “The relatively high prevalence of birth defects in American Indians/Alaska Natives warrants further attention.”