Why do kids get sick?
A massive new study aims to find out what's ailing America's children
Air. Water. Dust. Dirt. Body fluids. Genes. Food. Television. To see how they all interact in ways that sicken or protect children, researchers next year will begin fanning out across the country. They'll fill vials with tap water and capture samples of air. They'll scoop up soil, take note of lawns and outdoor plants. In rural Wisconsin and New York City, they will ask mothers for samples from umbilical cords and placentas. Babies and toddlers will contribute samples of urine, feces, and saliva. Mothers and fathers from the desert Southwest and small towns in Pennsylvania will sit down to answer detailed questions on their health, their illnesses, and their family histories of illness. Researchers will ask about exercise, diet, and how much TV kids watch.
In all, 100,000 children and their parents will be enrolled in the largest ever study of youngsters. Called the National Children's Study, it will be a 21-year odyssey of discovery, following children from the uterus to the threshold of adulthood. By carefully watching and waiting, researchers hope to gain a better understanding of major diseases that strike children, some of which are spreading alarmingly fast. The study will involve scientists from the National Institute of Child Health and Human Development, the National Institute of Environmental Health Sciences, the Centers for Disease Control and Prevention, and the Environmental Protection Agency.
Watching--and waiting. After four years in which the details of the study design were hammered out, it has garnered the support of groups ranging from the March of Dimes to the American Chemistry Council. The study has $12 million, enough to launch the first phase by selecting three to eight sites, which will each enroll 250 newborns a year for five years. The initial centers will serve as models, and eventually 96 locations will be chosen, reflecting the diversity of America. But with a price tag that could go as high as $2.7 billion over two decades, it's uncertain whether Congress, which called for the study in 2000, will continue to fund it. Researchers hope that success at the initial sites will prompt Congress to come through. The greatest hope is that medicine will find answers to questions about childhood diseases, including the growing childhood epidemics of diabetes, obesity, asthma, and autism.
Other long-term observational studies have paid off in countless lives saved. The Framingham Heart Study, for example, followed an initial 5,209 residents of the Massachusetts town since 1948. It is now recruiting the third generation of volunteers, the grandchildren of the original participants, and is credited with discovering the risk factors--such as hypertension, high levels of blood cholesterol, smoking, and lack of exercise--that contribute to heart disease.
Like heart disease, many of the childhood disorders afflicting growing numbers of children are likely to have more than one cause. They are the result of genetics interacting with environment, biology triggered by social circumstance. "You have to measure exposures early in life," says Peter Scheidt, the director of the study, "and follow the same individuals long enough for the condition to develop in order to understand."
Answers to a host of questions will take lots of watching and waiting: Does early exposure to pets cause asthma, or do Fluffy and Fido help protect against asthma? What causes a fetus--or the mother--to break from the normal 40-week pregnancy timetable and come early? Does excessive weight gain during pregnancy lead to obesity in children? What effect does exposure to lawn chemicals have on behavior and learning?
Seeking proof. Brenda Zepf has her own questions. Her son Nicholas, 10, was diagnosed with autism when he was 2 1/2. At 15 months, he had the language development of a 2-year-old. Then he started losing it. Coupled with his developmental reversal were severe gastrointestinal problems. Today, he survives on liquid only, unable to properly digest food. "Is that connected to the autism?" asks Zepf, a nurse. "You really can't tell. I think most of the physicians would agree that there's some neurological connection. Lots of neurochemicals are manufactured in the gut, so that's where I think some of it comes from." But she doesn't know for sure.
Zepf thinks about the Kansas row house where, during her pregnancy with Nicholas, there was major flooding in the Midwest that affected her neighborhood. "The water was contaminated. The mother next door to me was also pregnant, and she also has a child with autism. We both believe there was a connection," she says. But it's an anecdote, not scientific proof.
She wonders, too, about childhood vaccinations. Some people believe that thimerosal, which used to be part of many vaccines, contributes to autism. Several studies have found no evidence of a connection. "My other son had the exact same vaccinations. [He does not have autism.] Are there switches that get tripped only in some people?" she asks. No one knows.
Connections. Epidemiology is the kind of work that won't necessarily finger one medical culprit but will seek interactions among dozens of suspects. "There are a number of families that are concerned that certain kinds of pesticides or mercury are a cause of developmental disability and hyperactivity," Scheidt says. "There's another whole group who are convinced that diet is a cause of these things. Then there are studies showing that sitting in front of the TV for many hours a day contributes. How can you sort all that out without collecting information on all those multiple exposures?"
Increases in childhood disorders continue to confound. An estimated 16 percent of children 6 to 19 were overweight, according to a government survey spanning 1999-2002, up from 11 percent in 1988-1994. Some 2.6 million children 6 to 11 have been diagnosed with either attention deficit disorder or a learning disability. With a 10 to 17 percent annual increase in diagnosed cases, autism is the fastest-growing developmental disability. Asthma is the leading chronic illness causing school absences. From 1980 to 1993, asthma-caused deaths of children 19 and younger rose by 78 percent. "People will give you theories, but it's not clear," says Carol Berkowitz, president of the American Academy of Pediatrics. "Without doing a longitudinal study, we might never know."
So without answers, Laura Smith and her husband, Ronald, have pulled up the carpeting in their 50-year-old house in Dallastown, Pa. She and both her children, Emily, 10, and Collin, 6, have asthma. They've gotten rid of the venetian blinds, and they air out the drapes twice a year to get rid of dust. When Smith drives to work, she's irked at the cloud of pollution visible over nearby York. She believes there's a genetic component to asthma. But what triggers it, and what protects against it? Does living in an airtight home help or harm? Do her children wheeze because of pollutants to which they're exposed? Or has decreased exposure to the natural world somehow altered their immune systems?
The Smiths don't know because no one knows. With patience--and funding--answers may begin to emerge as this massive study progresses.
This story appears in the February 21, 2005 print edition of U.S. News & World Report.