Monday, August 09, 2010

Is all asthma genetic? Somehow I think not

I've written in various posts that I believe you must have the asthma gene in order to have asthma. Yet based on recent articles and studies I've read, I'm now thinking it may be possible to get asthma (or something similar to it) even if you don't have the asthma gene.

Consider exercise induced asthma (EIA). Scientists now claim that EIA is no longer a proper diagnosis, as EIB is more like it, or exercise induced bronchospasm. They say this because some people who do not have asthma may have EIA, or more properly EIB.

As I note in this post, " The best definition I could find (about EIB) came from this post at AAAAI.org, which notes exercise doesn't necessarily "cause" asthma, but that "hyperventilation (fast breathing) associated with exercise cools and dries the upper and lower airway resulting in the release of histamine and other substances that produce the bronchospasm (spasming of the muscles in the air passages in your lungs)."

Later I wrote the following, "Actually, according to Dr. Christopher Randolph, a clinical professor at Yale University who was interviewed by The New York Time's, EIA is not quite the same as asthma. He notes the "'preferred term' in the scientific community for exercise-induced asthma is exercise-induced bronchoconstriction, or EIB."

The idea here is that even if you don't have the asthma gene, and you are constantly irritating your airway with fast, rapid breathing in cool, dry air, you may be damaging your lungs long term.

This is also evidence in an upcoming post I will release soon about Occupational Asthma. With occupational asthma, it is believed that if you are exposed to the same chemicals day in and day out, your body may develop a sensitivity to is even if you don't have the asthma gene. The end result in non-asthma gene occupational asthma.

Say you are born premature with an immature immune system. Many of these kids are predisposed to get asthma.

A virus called respiratory syncicial virus (RSV) is a bug that most children are exposed to. So, in the first three months of life many scientists believe your immune system is developing, and if you're exposed to the RSV bug, and this causes you to develop RSV pneumonia, this may cause lung damage that may make these kids at increased risk for developing asthma whether they have the asthma gene or not.

So, say you are born premature and you are exposed to RSV. Now you have an even greater risk of getting asthma, whether you have the gene or not.

Other studies have me leaning this way, such as studies that show you have an 80% chance of developing asthma if you are born by c-section as opposed to vaginal delivery. Or studies that show athletes have a 40% greater chance of getting asthma later in life as opposed to non athletes.

Or, as I noted in this post, "What I also found stunning was that this article from the New York Times noted half of all cross country skiers, and 17 percent of Olympic-level distance runners, have been diagnosed with EIA. Likewise, according to the American Academy of Allergy, Asthma and Immunology (AAAAI.org), 23 percent of all olympians have EIA."

So, since it's expected that only 10% of the population has the asthma gene, and 80% of those who are born by c-section get asthma, then you have to assume, or surmise, that many of that 80% do not have the asthma gene.

Or am I missing something. What do you think? Discuss.

7 comments:

  1. I think asthma is likely not strictly genetic, but it probably had a genetic component. This is a well-known phenomenon in other areas of study. For example, one identical twin is far more likely to be homosexual if their twin is, but their twin's sexuality is no guarantee that they will be homosexual. If homosexuality was purely genetic, we could assume correctly that if one twin was homosexual, the other twin would be, too (since identical twins are identical genetically). But if there was no genetic component, one twin's sexuality would have no bearing on the other's.

    I think the same likely holds true for asthma. That's how you can have families with very strong family histories of it like mine (where the number of people without atopy in my extended family as far out as I've been able to trace can be counted on one hand), and in other cases, have it pop up out of the blue where there's no family history and no de novo genetic mutation.

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  2. take a look at www.vitaminD-for-asthma.com There is now significant data suggesting that asthma is another vitamin D deficiency disease. This site has all the information

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  3. I did not have asthma as a child. My adult-onset asthma came about during a bout of bronchitis at age 38...mild intermittent for many years, than with severe bronchitis in 03 became chronic, persistent moderate to severe. No significant allergies. Nor did my parents or brother have asthma. So, in my case, I don't see a genetic component...though there may be one buried deep in my DNA I am unaware of.

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  4. Thanks for your comments and the links. I agree. I think asthma is a genetic disorder, yet I think certain things can occur during one's life to (such as chemical inhalation for example) that can cause one to develop a non genetic form of asthma. It will definitely be interesting to see where future research will lead in this and other similar areas.

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  5. Yes, Mbarnes, I have heard of vitamin D effecting asthma. Yet does one develop asthma because they don't get enough vitamin d to cause non-genetic asthma, or does having asthma cause this to be low.

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  6. If asthma itself is genetic, then I'm a fail as I'm the only product of my parents and grandparents who has it. Yet all my siblings have atopic allergic eczema, hayfever, sinusitis. So, something in my parents' gene pool has caused us to all be allergic-yet I am still the only one with the asthma (Chronic severe, difficult to control variety!)

    Also, I grew up in sunlight-the vitamin D boosting sunlight of California-

    I now take high dose vitamin D, but that is because of my lowered bone density due to the Pred.

    Catch 22 there again!

    Cosky

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  7. I believe eczema, hay fever, sinusitis, and asthma are all from the same gene. So in your case asthma would probably be considered genetic. Although there's really no way of knowing for sure.

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