Asthma has increased dramatically over the last few decades, with 500 adults dying of asthma each year (and about 20 kids). That's scary stuff. I know for my family, we tried to keep the indoor air clean when our kids were babies, especially since my husband has a number of allergies and asthma. We figured that keeping the air as clean as possible would help boost their immune systems and hopefully ward off asthma and allergies. Boy, were we ever wrong. Despite having cats when my kids were born, my son was born with a host of allergies, and at five years old was diagnosed with a number of environmental allergies along with asthma.
Well, crap. All that good intention was for naught, because a new study out of Sweden has demonstrated that kids who are exposed to farm animals or dogs within the first few years of their lives have a reduced risk of asthma. More than one million children between the ages of one- and five-years old were used in the study, which was conducted over a decade. Dr. Marla Shapiro discussed the study on Canada AM, explaining that by age six, there was a significant decrease in asthma in families, regardless of family history. This is a big deal, because one of the leading causes of school absence and hospitalization for kids in Canada is asthma. It's a nasty thing.
This study seems to support the hygiene theory -- we're too clean, apparently. Now, the hygiene hypothesis itself isn't really news; scientists have been pointing fingers to our obsession with being uber-clean for many years now. Remember the study that demonstrated babies exposed to mouse dander and cockroach poop were less allergic and asthmatic than their cleaner counterparts? (Barf.)
What's not clear in all these studies is just why exposure to animals (or mouse dander, or dirt, or cockroach poop) seems to help ward off asthma. Is there a specific microorganism kids are exposed to that helps bolster immune systems? Or is it related more to the general lifestyle of those exposed to dogs and farm animals -- more time outside, potentially more exposure to dust, dirt and other organisms? It's certainly a fantastic start with potential to explain some of the mystery around the increase in asthma in recent decades.
None of this is of immediate use for kids like my son, but it sure is interesting to see theories being formed, and answers being discovered. Here's hoping we can find the ket to preventing asthma in the near future.