Recent research conducted by an MSU professor discovered that firstborn children are more likely to suffer from asthma and other allergies.
Wilfried Karmaus, an associate professor of epidemiology, found that firstborns have higher levels of cord blood immunoglobulin, a protein determined to be a risk factor for asthma and other allergies, such as hay fever.
Karmaus said changes in the mother’s womb after the birth of a first child are reasons for the difference.
“The immune system is changed to a different state,” he said. “The change comes when you are exposed to some infections and the immune response is triggered. The idea was that if you have other brothers or sisters, the response would be triggered to a normal immune response.”
Karmaus and other researchers from England and Australia examined 1,000 children born in the United Kingdom’s Isle of Wight between 1989 and 1990.
Of the firstborn children, 16.5 percent had high cord blood immunoglobulin levels.
Similar levels were found in 12.8 percent of children with one older sibling and in 8 percent of children with two or more older siblings.
“What we are saying is the effect occurs before birth,” Karmaus said. “There’s something in the uterus of the mother when she’s pregnant. That’s the main idea.”
Karmaus said previous theories used to determine the reasons for developing asthma and other allergies involved considering where a child lives.
That reasoning incorporated the idea that cleaner, more industrialized societies would cause children to develop fewer bacterial infections but become more vulnerable to allergies, Karmaus said.
But Karmaus said it is important to find solutions to the problem, regardless of their origins.
“The basic idea is that allergies are increasing in the more industrialized world in the past 30 years,” he said.
But Sheldon Spector, a clinical professor of medicine at the University of California at Los Angeles, said Karmaus’ findings could overlap with other factors.
“I think it’s too complicated to be generalizing because there are too many environmental factors,” he said. “There are too many other variables, like being exposed to dogs and cats or being in a city or in the country.”
Spector said recent research such as Karmaus’ is in introductory stages.
“We’re just getting some of these new theories and they’re changing considerably,” he said. “Basically what it comes down to is although it’s possible, it may differ in different cultures and may differ because of different situations.”
