THURSDAY, Oct. 28, 2004 (HealthDayNews) -- Clues about childhood asthma and allergies may be contained in umbilical cord blood, says a study in the latest issue of Thorax.
The findings suggest that high levels of immunoglobulin E (IgE) in a newborn's umbilical cord may be more important in development of childhood asthma and allergies than exposure or lack of exposure to allergens after birth.
IgE is an immune system response that indicates sensitization to allergens such as grass pollens, house dust mites and pet dander.
Researchers studied samples of umbilical cord blood taken from 1,300 children. The children were assessed at ages 1, 2, 4 and 10 to determine if they'd developed asthma and/or allergies. By age 4, 20 percent of the children had become sensitized to allergens. That figure rose to 27 percent by age 10.
The study found that children born with high levels of IgE in their umbilical cord blood were about twice as likely to be sensitized to allergens.
Ten percent of the children were diagnosed with asthma by the time they were 1 to 2 years old. That rose to 15.2 percent by age 4. At age 10, that figure was about 13 percent.
High levels of IgE in umbilical cord blood were not associated with the development of asthma up to age 4. But the study found that children with high IgE cord blood levels were about 66 percent more likely to have been diagnosed with asthma by age 10. This suggests a late-onset form of asthma, the researchers said.
Children who didn't develop allergies were more than three times as likely to have asthma by age 10 if they had high IgE cord blood levels.
The study authors wrote that the findings suggest that fetal immune system programming could have more influence on development of childhood allergies than what happens after a child is born.
The American Medical Association has more about allergies.