The benefits of roaches? Babies exposed to dirt and germs may have less allergies

Living with cockroaches may have its benefits after all – for newborns, that is.

A new study published in the Journal of Allergy and Clinical Immunology revealed that babies who are exposed to household dirt, pet dander and even allergens from roaches and rodents may have a lower risk of developing allergies as they grow up, Medical Xpress reported.

To conduct their research, scientists at Johns Hopkins Children’s Center collected data from 467 inner-city newborns, following them for three years and monitoring blood tests for signs of allergies.  Simultaneously, the team also measured the levels of allergens and bacteria in the children’s homes.

Overall, children who were exposed to cat and mouse dander, as well as cockroach droppings, before their first birthdays had lower rates of allergies and wheezing, as opposed to children who were not exposed.  The protective effects were also amplified if the homes contained various types of bacteria: 41 percent of the children who didn’t wheeze or have allergies grew up in bacteria and allergen-filled homes, compared to 8 percent of kids with allergies.

These findings support a well-established theory known as the hygiene hypothesis, which argues that children growing up in clean environments are prone to developing allergies later in life.  The idea behind the theory is that the lack of exposure to infectious agents during childhood leads to poor development of the immune system, since it doesn’t have to work as hard to fight off disease.  The result: a weaker, more highly allergic immune response.

The researchers noted that their study shows that environmental exposures are significant, especially just after a child is born.

"Our study shows that the timing of initial exposure may be critical," said study author Dr. Robert Wood, chief of the division of allergy and immunology at the Johns Hopkins Children's Center, in a press release. "What this tells us is that not only are many of our immune responses shaped in the first year of life, but also that certain bacteria and allergens play an important role in stimulating and training the immune system to behave a certain way."

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