A Wonderful Mystery

Last fall epidemiologist Cynthia Ferre got some of the best, but most mystifying news of her career. Ferre, who works for the Centers for Disease Control and Prevention, knows all too well that the U.S. has one of the worst infant-mortality rates in the developed world, with preterm African-American babies almost four times as likely to die as infants than white babies. So why had the black-white infant-mortality gap apparently disappeared in one county in Wisconsin, a state with some of the worst infant-mortality rates in the nation for blacks? (Article continued below...)

Even an isolated improvement in infant mortality could have far-reaching ramifications for the nation's overall health and health-care costs, but only if authorities can figure out what's actually been happening in Dane County. "This is a very big deal; we've never seen this before," says Ferre, who has been tracking infant-mortality disparities and maternal health issues for the CDC for 18 years.

America's infant-mortality rate has long been both a black mark on the reputation of our health system, and a financial burden. The U.S. ranks 29th in the world, tied with Malta and Slovakia for the second-worst infant-mortality rate among developed nations. In most poor countries infant deaths are often caused by treatable infections like diarrhea, pneumonia, or malaria. But in developed countries the deaths are more often caused by extreme prematurity or birth defects. According to a report by the Institute of Medicine, the annual cost associated with preterm birth in the U.S.—at its bare minimum—is $26.5 billion. It's a grim picture, and nothing really seems to have helped in recent years. Except, it turns out, in Dane County, whose 470,000-odd residents are mostly divided between the capital, Madison, and the surrounding rural areas of southern Wisconsin.

Dr. Thomas Schlenker, director of public health for Madison and Dane County, is leading the investigation into the turnaround, with help from the University of Wisconsin School of Medicine and Public Health and the state Department of Health Services. When Ferre first got an e-mail from Schlenker last fall, she was skeptical. "We're really not used to seeing improvements like this," she admits. She pored through the Dane County numbers, which were small, but consistent over time. Between 1990 and 2001, the county recorded 73 black infant deaths. The figure dropped to 17 between 2002 and 2007, representing an incredible 67 percent decline from 1990. It is the first known example of the black-white gap closing in any one state or county.

What was behind this extraordinary improvement? "We've got dozens of lines of investigation out," says Schlenker. The first thing he and his team of investigators looked at was an obvious lead. In the '90s, the Healthy Start Program in Wisconsin—Medicaid for pregnant women—was expanded to include almost all low- and middle-income pregnant women. That would seem at first to be the answer, especially since the change was widely advertised in Dane County. But it applied statewide, and other parts of Wisconsin with populations similar to Dane County still have dismal infant-mortality rates. At 17.6 per 1,000 births, Wisconsin's infant-mortality rate for African-Americans is among the highest in the nation, and is just below that of the Gaza Strip. In certain cities—Racine, for instance—it is a staggering 23 per 1,000 births.

Ferre is also trying to solve the mystery. Looking for possible causes, she wondered if it might be traced to the way fetal-death trends were tallied—if, for example, a baby was born but classified as a fetal death even though it had been outside the womb for several minutes before dying. "That would artificially reduce the rate of infant death," says Ferre. But she says that appears unlikely because fetal and infant deaths were both going down at the same time. She asked about any major changes to the population. Research indicates that foreign-born African immigrants have significantly better birth outcomes—closer to whites—than U.S.-born black women. But while the county's African-American population has doubled in the past 20 years, Schlenker has found that only 10 percent of the newcomers were foreign-born. "That wasn't it, either," says Ferre. Nor was it due to improvements in protocols at local hospitals. Schlenker's team found "no significant changes in the local health care systems, infrastructure or practice that corresponded to the improvements," according to a CDC paper written by Schlenker and his colleagues and reviewed prepublication by Ferre. "They also have a decrease in the number of teen mothers and pregnant black women who smoke—all established risk factors that support the outcome," says Ferre. "But that is unlikely the whole answer."