THREE of four birth defects in this country are epidemiologic mysteries, says Godfrey Oakley, MD, chief of the birth defects branch in the CDC's Center for Environmental Health and Injury Control, Atlanta, Ga.
"We don't know if we're looking for 50 [causes] or, my guess is, closer to 100 000 different disease processes," he says. "The challenge is to find these various and sundry causes," Oakley says, that together account for the fifth leading cause of years of potential life lost in the United States.
Oakley keeps track of reported birth defects and mental retardation, putting them into 150 categories in all and analyzing the numbers every 6 months for any changes or emerging patterns. "So much is associated with nondescript poverty," he says, and lack of prenatal care is often blamed. But, Oakley says, he suspects the latter is "overrated" as a cause by itself.
While incidence does go