Post by Brooke on Mar 4, 2004 2:01:34 GMT -5
Thursday, March 4, 2004
Petting those allergies away
Denise Flaim
Animal House
Meet our imaginary couple.
They date, fall in love and marry. Not yet ready to have children but looking for something to nurture, they acquire a cat (or two or three) or a dog (or two or three).
Years pass and, heeding their ticking clocks or the pleading of wanna-be grandparents, they decide to add a two- legger of their own to the household.
But once the wife is pregnant, the questions from the well- and not-so-well-meaning friends and family begin: What if the baby is allergic?
Guilt-ridden, the couple give away their beloved animals to friends, or turn them over to rescue, or drop them off at a municipal shelter.
It's a common scenario - and, experts say, an unnecessary one.
"I think people have been misled for a long time, and that's caused some problems," says Dennis Ownby, a professor of pediatrics at the Medical College of Georgia in Augusta.
In fact, a growing body of research draws a conclusion that is the antithesis of our imaginary couple's: That growing up with animals, especially at an early age, may actually help prevent allergies.
A study published in August in the Journal of the American Medical Association, for which Ownby was the lead author, compared children who were exposed to cats and dogs during their first year of life to those who were not. It concluded that having two or more cats or dogs in the home reduced the chance of a child's not having allergies by age 6 or 7 by slightly more than 70 percent.
Other studies, Ownby says, have come to similar conclusions. "There is a growing consensus among researchers that there probably is a protective effect against allergies of growing up in close contact with animals."
What is up for debate is exactly why this is so. One theory suggests that animals in the home increase levels of a chemical called endotoxin, which is the breakdown product of common bacteria. The thinking is "that exposure to endotoxin, especially early in life, shifts the body's immune system in such a way that allergies are unlikely to occur," Ownby explains.
Another school of thought posits that exposure to very high levels of allergens "induces what immunologists call 'tolerance' in a person," he continues. "It simply means your immune system recognizes an allergen but doesn't respond to it."
One area where the studies part ways is in how generic the allergy benefits are. Some suggest that high exposure to cats lessens the likelihood of an allergy to cats only. Others, including the one Ownby was involved in, show the opposite: that high exposure to cats also meant that the children were less likely to be allergic to other animals, as well as common allergens such as dust mites or ragweed.
At what age does a child benefit most from being around animals? The sooner the better, Ownby says.
"Our information and most other literature suggest that the anti-allergy effect is most prominent in the first year of life. And perhaps it only occurs in the first year of life - and probably the first months."
While it's not known how much exposure is enough to trigger an anti-allergy benefit, "it does seem probable that the more exposure, the better," Ownby says, pointing to European studies that showed that women who worked on farms throughout their pregnancies and returned to work soon after delivery or brought their child with them "dramatically reduced the chance of that child being allergic."
And the more the merrier: In Ownby's study, living with one dog had some effect on a child's reduced risk of allergies, while living with two or more had a greater effect.
While all this is good news for prospective parents who have animals in their homes, it poses a dilemma for those who don't. There is probably no worse time to introduce a new animal into your household than when a new baby is expected. Like newborns, puppies and kittens need a tremendous amount of time, training and socialization - things that will be in short supply when the bundle of joy arrives.
Also, if you are lukewarm about the idea of introducing a dog or cat into your household in the first place, these study results are not a good reason to ignore your instincts and get one anyway.
And, finally, remember that old line about death and taxes.
"Our study, like all these others, talks about decreasing risk, not an absolute protection," Ownby concludes. "Nothing is guaranteed."
Email: denise.flaim@newsday.com
Copyright © 2004, Newsday, Inc.
Petting those allergies away
Denise Flaim
Animal House
Meet our imaginary couple.
They date, fall in love and marry. Not yet ready to have children but looking for something to nurture, they acquire a cat (or two or three) or a dog (or two or three).
Years pass and, heeding their ticking clocks or the pleading of wanna-be grandparents, they decide to add a two- legger of their own to the household.
But once the wife is pregnant, the questions from the well- and not-so-well-meaning friends and family begin: What if the baby is allergic?
Guilt-ridden, the couple give away their beloved animals to friends, or turn them over to rescue, or drop them off at a municipal shelter.
It's a common scenario - and, experts say, an unnecessary one.
"I think people have been misled for a long time, and that's caused some problems," says Dennis Ownby, a professor of pediatrics at the Medical College of Georgia in Augusta.
In fact, a growing body of research draws a conclusion that is the antithesis of our imaginary couple's: That growing up with animals, especially at an early age, may actually help prevent allergies.
A study published in August in the Journal of the American Medical Association, for which Ownby was the lead author, compared children who were exposed to cats and dogs during their first year of life to those who were not. It concluded that having two or more cats or dogs in the home reduced the chance of a child's not having allergies by age 6 or 7 by slightly more than 70 percent.
Other studies, Ownby says, have come to similar conclusions. "There is a growing consensus among researchers that there probably is a protective effect against allergies of growing up in close contact with animals."
What is up for debate is exactly why this is so. One theory suggests that animals in the home increase levels of a chemical called endotoxin, which is the breakdown product of common bacteria. The thinking is "that exposure to endotoxin, especially early in life, shifts the body's immune system in such a way that allergies are unlikely to occur," Ownby explains.
Another school of thought posits that exposure to very high levels of allergens "induces what immunologists call 'tolerance' in a person," he continues. "It simply means your immune system recognizes an allergen but doesn't respond to it."
One area where the studies part ways is in how generic the allergy benefits are. Some suggest that high exposure to cats lessens the likelihood of an allergy to cats only. Others, including the one Ownby was involved in, show the opposite: that high exposure to cats also meant that the children were less likely to be allergic to other animals, as well as common allergens such as dust mites or ragweed.
At what age does a child benefit most from being around animals? The sooner the better, Ownby says.
"Our information and most other literature suggest that the anti-allergy effect is most prominent in the first year of life. And perhaps it only occurs in the first year of life - and probably the first months."
While it's not known how much exposure is enough to trigger an anti-allergy benefit, "it does seem probable that the more exposure, the better," Ownby says, pointing to European studies that showed that women who worked on farms throughout their pregnancies and returned to work soon after delivery or brought their child with them "dramatically reduced the chance of that child being allergic."
And the more the merrier: In Ownby's study, living with one dog had some effect on a child's reduced risk of allergies, while living with two or more had a greater effect.
While all this is good news for prospective parents who have animals in their homes, it poses a dilemma for those who don't. There is probably no worse time to introduce a new animal into your household than when a new baby is expected. Like newborns, puppies and kittens need a tremendous amount of time, training and socialization - things that will be in short supply when the bundle of joy arrives.
Also, if you are lukewarm about the idea of introducing a dog or cat into your household in the first place, these study results are not a good reason to ignore your instincts and get one anyway.
And, finally, remember that old line about death and taxes.
"Our study, like all these others, talks about decreasing risk, not an absolute protection," Ownby concludes. "Nothing is guaranteed."
Email: denise.flaim@newsday.com
Copyright © 2004, Newsday, Inc.