Link between OSA and the "beer gut"

[split_city]

Hi all. This is my first post in this forum. I'm currently a PhD student working in the area of sleep apnoea. I have been looking at one potential mechanism which might explain why sleep apnoea is predominant in males.
While it is clear that the risk of developing sleep apnoea increases when you put on extra weight, the actual distribution of where this fat is stored is known to be a better predictor of sleep apnoea. For example, fat around the neck is a better predictor of sleep apnoea compared to your body mass index.

Alternatively, I have been looking at the link between abdominal obesity ("beer gut") and upper air collapsibility. The belief is that males who have a bigger belly have increased pressure inside the abdomen. This increased pressure is a likely force to push the diaphragm and airways upwards towards the head, making the upper airway more "floppy" and therefore easier to collapse. Sleep apnoea is known to generally be more severe when you're on your back.

Therefore, I looked at the effect of increased pressure inside the abdomen on upper airway collapsibility during sleep in obese male sleep apnoea patients. I increased pressure inside the abdomen by inflating a large pressure cuff (ala bloody pressure cuff) which was placed around the abdomen. I then assessed how collapsible the airway was with and without abdominal compression. In terms of the results, the airway was slightly more collapsible when there was increased pressure inside the abdomen. While the effect was small, I discovered a very strong relationship between pressure inside the stomach and upper airway collapsibility during times when the cuff wasn't inflated. Basically, this might mean that pressure inside the abdomen is perhaps an important predictor of how collapsible your airway is, but these effects cannot be simply simulated by using a cuff to simulate abdominal obesity.

Some food for thought

Daniel

[Snoredog]

man I hate to burst your PhD learning bubble, but OSA is mainly the tongue falling into the back of the throat, not the airway collapsing due to fat around the neck or diaphragm pressure. That's why it is worse on your back than your side.

since I'm on a roll here, not everyone that has OSA is obese, it is not a disorder found predominately in men either, women snore worse than men

go through life with those phenotypes you described and you'll miss half the OSA population because they didn't fit your "mold".

as for the "beer gut" association? I think they have already identified that one also, its called dunlap disease.

[split_city]

man I hate to burst your PhD learning bubble, but OSA is mainly the tongue falling into the back of the throat, not the airway collapsing due to fat around the neck or diaphragm pressure. That's why it is worse on your back than your side.

since I'm on a roll here, not everyone that has OSA is obese, it is not a disorder found predominately in men either, women snore worse than men

go through life with those phenotypes you described and you'll miss half the OSA population because they didn't fit your "mold".

as for the "beer gut" association? I think they have already identified that one also, its called dunlap disease.

oh dear, i better quit then! I better inform the supervsior that he doesn't know what he is talking about

While what you said is all true, none of them fully explain OSA. Either one of these phenotypes or a combination of them generally don't explain anymore than 30% of the variance in OSA That's the problem with OSA. There's not one particular cause

[CollegeGirl]

Would you mind telling that to 95% of doctors, then, who tell all their patients with OSA that the solution is weight loss?

(Seriously, though, I can't even begin to tell you how many people come onto these boards and complain that they lost all the weight [some through drastic surgical methods] and still have OSA. They're shocked, as their docs told them all they needed to do was lose weight. It's sad).

[Snoredog]

maybe a picture would help:

[split_city]

Would you mind telling that to 95% of doctors, then, who tell all their patients with OSA that the solution is weight loss?

(Seriously, though, I can't even begin to tell you how many people come onto these boards and complain that they lost all the weight [some through drastic surgical methods] and still have OSA. They're shocked, as their docs told them all they needed to do was lose weight. It's sad).

Like I said in my opening post, there are a number of causes of OSA. Therefore, weight loss (or surgery) will not always help. I have seen diagnostic studies of many patients who have undergone surgery who have shown no improvement in their OSA. On the otherhand, I come across patients all the time who have lost weight and their OSA severity decreases or goes away. All the sleep physicians I know never say that weight loss wiill guarantee that their OSA will disappear. However, a lot of research has shown in a large percentage it will.

This is why research needs to be conducted to try and further our understanding of the disease

[split_city]

maybe a picture would help:

I'm aware that posterior movement of the tongue is a potential cause of OSA but there are many others. The tongue doesn't always flop back in all cases. If this movement of the tongue was the only cause, why does the airway collapse when in the lateral position or when laying on your stomach?

There have also been a few studies which have shown that central obesity (waist-to-hip ratio) was in fact a better predictor of OSA than neck fat/circumference.

Again, I agree that tongue movement is a potential cause of OSA, but it certainly doesn't fully explain the disease.

[CollegeGirl]

If no one phenotype tells us the cause of OSA, how can the answer for "a large percentage" be weight loss? Wouldn't it only be a solution for OSA caused by extra fat around the neck?

I'm also highly interested in the whole chicken and egg thing - is it the OSA that instigates the weight gain, or the weight gain that instigates the OSA? Given what we now know about leptin and ghrelin, and the fact that OSA causes severe imbalances in both, and the fact that improper levels of these make people feel always hungry and never full...and given that the body craves carbohydrates and sweets when it is sleep deprived, as it needs quick energy, and the fact that excess carbs can contribute to weight gain....and given that we know that sleep deprivation can keep one from having the energy to be active at all, much less exercise...it just seems to me that this is a different way of looking at OSA and weight gain that the scientific community just has not explored yet.

Incidentally, surgery is notorious around here for being unsuccessful in the treatment of apnea. It is my understanding that the majority of patients with severe apnea who undergo surgery for OSA still have moderate to mild sleep apnea when it is over, at best, and still need a CPAP. Some on this forum have even told of surgeries making their OSA worse than when they started, and untreatable. Among the surgeries, the MMA/GA is the only one that has a relatively good reputation around here.

[split_city]

There are a number of factors associated with obesity with are thought to contribute to OSA. Some changes which occur following weight loss include:

1) reduction of neck fat and fat around the upper airway
2) reduction in abdominal obesity
3) improved ventilation/perfusion
4) improved respiratory muscle activity
5) increased lung volume

Once again, all or some of these can contribute to OSA. However, there are other factors which can contribute to OSA which aren't associated with obesity. Nevertheless, Terry Young found this "an increase of 1 SD in any measure of body habitus was related to a threefold increase in the risk of an apnea-hypopnea score of 5 or higher."

Yes I agree that about the "chicken and the egg" question. For example, a healthy weight individuals starts experiencing OSA, becomes tired, doesn't exercise, puts on more weight, OSA severity increases, patients gets more tired, patient is less active, patient becomes depressed...etc etc.

The problem with these types of forums is that I'm sure many unhappy OSA patients who have undergone unsuccessful surgical procedures would want to let off their "steam" via this type of medium. I'm sure it would be biased towards them compared to patients who have been successfully treated.

[Wulfman]

Here's a link that I've posted a few times before.

http://www.sleepreviewmag.com/article.p ... 006/07&p=8

I think you should change your study to "How many people had sleep deprivation in the years leading up to their onset of OSA?"

Whether we were spending many hours studying, burning the candle at both ends....trying to make a living for our families, or pressure from our employers to complete assigned projects at work, or just the nature of our work, in general, that led to poor sleep.....that led to OSA.
I'll bet it would be about 100%.

Then, there are the physiological and genetic factors, too.

Insufficient sleep doesn't contribute to good body metabolism.
There's a reason for the "beer gut" and it ain't just beer.

Den

[split_city]

I can only study so much in 3 years!!

[blarg]

maybe a picture would help:

I agree entirely.

[bast]

hahahaha!

blarg, does your kitty have a beer gut, and so needs to take this thread very seriously?

what a great shot!

[RosemaryB]

Hi all. This is my first post in this forum. I'm currently a PhD student working in the area of sleep apnoea. I have been looking at one potential mechanism which might explain why sleep apnoea is predominant in males.

Hello Daniel, and welcome to the forum. I'm wondering if you could study the same thing in females as well (or instead).

My story is that I went to my GP 4-5 years ago and asked to be tested. He talked me out of it, since I'm a female, BMI of 21.5 based on weight, with a thin neck, and I don't snore, or only rarely and then gently. I suspect that there are many undiagnosed women out there due to confirmation bias, a problem not only in diagnosis, but also in research.

I finally got diagnosed recently, but am thinking of the large impact untreated OSA has had on my professional and personal life in the years since I made this request. Obviously I feel strongly about this.

Having done doctoral level research myself, I can appreciate the need to narrow one's topic! However, narrowing one's topic in a way that perpetuates confirmation bias results in flawed research.

If you wish to study a link between OSA and hip/waist measurement, including both genders (or even studying women) would make a significant contribution and would strengthen your research. If I were on your committee, this is certainly one thing I would want to explore with you. Including gender would make a more sophisticated contribution to the field, and probably a more original one.

One thought is that after menopause, many women also get a gut and this is when the incidence of OSA increases in women (supposedly). In my own case, my weight is average but my waist is not what it once was. KWIM?

Good luck on your research. You will find some good dialogue on this site that may help you refine your study.

[DP]

Rosemary, how old are you? The reason I ask is because women will typically develop sleep apnea during and after menopause. Now this is not to say younger women don't have sleep apnea, it is just that the incidence levels is not has high and usually specific to being obese.