Interesting finding..

[split_city]

Our lab recently found that waist-to-hip ratio was a better predictor of OSA than neck circumference or fat around the upper airway in BMI-matched males and females. This finding backs up a few other studies, as well as my abdominal compression study, showing that central obesity may also be a potential cause of OSA.

[mhacker]

I hate you.

[split_city]

I hate you.

Great input

[WillSucceed]

Well, perhaps not helpful input, but it did make me laugh! A dollop of humour never hurt anyone.

[Vonon]

Does this mean a cure is possible by just making my hips bigger?

[split_city]

Does this mean a cure is possible by just making my hips bigger?

hehe...if only it was that easy! But then your BMI would increase as well. Another important predictor of OSA

[Vonon]

Rats! Foiled again!

[ozij]

Our lab recently found that waist-to-hip ratio was a better predictor of OSA than neck circumference or fat around the upper airway in BMI-matched males and females. This finding backs up a few other studies, as well as my abdominal compression study, showing that central obesity may also be a potential cause of OSA.

Do you know that for school age k-12 children, one of the best predictors of mathematical knowledge is their shoe size? Would you say this finding shows foot size may be a potential cause of mathematical knowledge? Age is the mediating variable in this example.

Correlations indicate nothing about causes. They just show that two phenomena appear reliably together.

I'm curious: Did your lab control for gender? Is the finding true - separately - in both men and women? Have you published it? Could you please give links to the other studies you mention?

Waist to hip ratios are very different in men and women, and the "apple shape" waist to hip ratio is more prevalent in men and in people with diabetes or in general with what they call "metabolic syndrome". Central obesity is correlated with metabolic syndrome. Maybe the waist to hip ratio you saw was caused by metabolic syndrome, which, in turn, was caused by OSA?

The correlation between metabolic syndrome and OSA has been pointed out in the past - it is even possible that OSA - may have a part in causing metabolic syndrome - studies have shown metabolic syndrome appears more in people with OSA that it does in those with the same BMI who do not have it.

http://ajrccm.atsjournals.org/cgi/conte ... /165/5/670
http://eurheartj.oxfordjournals.org/cgi ... t/25/9/735
http://www.chestjournal.org/cgi/content ... 131/5/1387


O.

[split_city]

Correlations indicate nothing about causes. They just show that two phenomena appear reliably together.

I totally agree . This study was not a "cause-and-effect" type study. This is why I conducted my abdominal compression study (see link between OSA and the beer gut thread). Relationship studies can never definitively describe causality. Even neck circumference, which is throught to one of the most important predictors of OSA, rairly explains anymore than 20-30% of the variance in terms of AHI. This indicates there are other causes of OSA. The fact is, there is no one cause of OSA. However, we can look at relationships to help us understand factors which may/are likely to contribute to OSA

I'm curious: Did your lab control for gender? Is the finding true - separately - in both men and women? Have you published it? Could you please give links to the other studies you mention?

waist-to-hip ratio was found to be a predictor of OSA for the entire group (males and females) and also in males and pretty sure not in females. Interestingly, the main objectives of the study did not revolve around abdominal obesity. The study was set out to look at differences neck fat in age and BMI-matched males and females. It hasn't been published yet. Here are some studies showing the central obesity was a predictor of OSA.

Deegan and McNicholas. Predictive value of clinical features for the obstructive sleep apnoea syndrome (1996). Eur Respir J 9:117-124

"After controlling for BMI and age, waist circumference correlated more closely with AHI than neck circumference among males, while the opposite was true among females."

Grunstein et al. Snoring and sleep apnea in men: association with central obesity and hypertension (1993). Int J Obes 17: 533-540

"The best explanatory variables for sleep apnoea were waist and age only"

Waist to hip ratios are very different in men and women,

I understand that. Our group has been looking at one potential aspect of abdominal obesity and how it may impact the upper airway.

and the "apple shape" waist to hip ratio is more prevalent in men and in people with diabetes or in general with what they call "metabolic syndrome". Central obesity is correlated with metabolic syndrome. Maybe the waist to hip ratio you saw was caused by metabolic syndrome, which, in turn, was caused by OSA?

Perhaps, who knows.

I just asked someone involved in the study and they said they did not ask whether each patient had metabolic syndrome.

However, I showed that increased pressure inside the abdomen, a common feature in centrally obese males, resulted in an increase in upper airway collapsibility. My patients did not have metaboloc syndrome.

The correlation between metabolic syndrome and OSA has been pointed out in the past - it is even possible that OSA - may have a part in causing metabolic syndrome - studies have shown metabolic syndrome appears more in people with OSA that it does in those with the same BMI who do not have it.

http://ajrccm.atsjournals.org/cgi/conte ... /165/5/670
http://eurheartj.oxfordjournals.org/cgi ... t/25/9/735
http://www.chestjournal.org/cgi/content ... 131/5/1387


O.

All valid but your are only looking at relationships, which is what you were talking about earlier.

You must understand that I never said that abdominal obesity causes OSA. However, it may contribute to it. How it does is anybody's guess. I have been looking at one impact that abdominal obesity, and hence increased abdominal pressure, has on upper airway function.

_________________

CPAPopedia Keywords Contained In This Post (Click For Definition): AHI

[DreamStalker]

What was the sample size of the study?

Re: relationships -- North America has the highest incidence of tornados in the world and there is a strong correlation with the fact that the North American population drive their automobiles on the right side of the road (... or the wrong side, depending upon your perspective) … therefore driving on the right side of the road causes tornados. Spurious relationships have a way of appearing factual.

So what are the physiological mechanics of central obesity that has prompted you to hypothesize that belly fat is more closely related to OSA than neck fat?

[Guest]

split-city,

I think my own case indicates an unknown cause which contributes to both the OSAHS and abdominal obesity.

I am female with severe abdominal/stomach fat although my legs, thighs, buttocks, etc. have very little fat. Think of a ball with stick legs and no behind. My waist size is 40 inches. This pattern of deposition began long before puberty - sometime during early childhood.

I believe that I have had some form of sleep-disordered breathing also since childhood, but that the sleep-symptoms came BEFORE any significant weight gain. I was a very tired child, especially upon waking up in the morning after having had a full nights sleep.

On a tangent: A psychiatrist at a well regarded university discussed with me the possibility that this distribution of fat was the expression of a secret desire to become pregnant. (And I paid thousands of dollars for this "professional" medical treatment). This was years ago, but even then I told him that was ridiculous.

I was diagnosed finally at age 44 with OSAHS (moderate AHI of 17 in nonREM and severe AHI of 65 in REM - and what causes that difference?).

My question is this: Is there any info about the cause of the fat being deposited so specifically in the abdomen/stomach? Why am I so different from normal pear-shaped women? Is there anything that is even theorized to help shift anyone from the "apple" to the "pear" shape?

Thanks.

[mhacker]

What was the sample size of the study?

Re: relationships -- North America has the highest incidence of tornados in the world and there is a strong correlation with the fact that the North American population drive their automobiles on the right side of the road (... or the wrong side, depending upon your perspective) … therefore driving on the right side of the road causes tornados. Spurious relationships have a way of appearing factual.

So what are the physiological mechanics of central obesity that has prompted you to hypothesize that belly fat is more closely related to OSA than neck fat?

You may be on to something. I drive a British car (MGB) near a large metropolitan city (San Francisco) on the wrong side of the road (from the car's POV) - I have a friend that drives an American car (Ford) near a large metropolitan city (London) on the wrong side of the road (from the car's POV) - AND WE BOTH HAVE OSA

OMG it is foreign cars on the wrong side of the road causing OSA.

[socknitster]

There is a thread going on here that discusses the genetics of apnea and obesity. It seems there may be codes next to each other on the same gene that predispose some toward apnea and obesity.

Whether one causes the other isn't as important as knowing they often coexist. Apnea patients are tired of being told they are fat--especially the ones who aren't. I for one, know FOR SURE that my abdominal fat was gained AFTER my symptoms of apnea began. Had my doctor known about split_cities research findings, perhaps he would have been more likely to diagnose me at a younger age, instead of 35. The idea here isn't to call apnea patients fat and say shame on them, the idea is to find ways to screen for and diagnose more people so that they don't suffer as long as many of us have. Am I right, split_city?

After all, how many of us say we suffered for 10-15 years or more? Science is trying to figure out how to better predict who has it and who doesn't by finding SOMETHING, no matter how imperfect--something is better than nothing!--OBJECTIVE TO MEASURE to predict who has this syndrome.

Personally, I think the best thing they could do is for every patient who comes in with fatigue and depression issues give them a sleepiness questionaire. What is that called, the epworth test or something. That would probably catch more people than measuring waist to hip ratio since many of us were thin when symptoms started.

By the way, I went back to the gym for the first time since my diagnosis and WOW! What a difference in what I was able to do--twice as far in half the time and have energy to spare. It is amazing the difference xpap has made in my life. I'm so grateful to have a chance to turn my life around. Wait til you see how fast the fat falls off!

jen

[DreamStalker]

I was a skinny runt until I started playing in a kid football league when I turned 9 YO. At that point, I started putting on weight although I would not consider myself “fat” at the time. I gradually became more stocky and somewhat buff into my early twenties (when I first discovered I snored) due mostly to the fact that I switched from playing football to weight lifting in high school. By the time I turned 30, the weight slowly began to add up as I decreased my physical activity to mostly just hiking/backpacking in the wilderness as part of my graduate studies/duties. Once I started working in an office environment my physical activity went pretty much to zero and my OSA symptoms started kicking in with a vengeance, enhancing the weight gain.

While OSA certainly contributed to my weight gain and my weight gain to OSA, a decrease in my physical activity I think may have had a strong correlation to my OSA/fat gain.

Like Jen, I now have the energy to do so much more except that during the last year I have been using my energized time to catch up on so many projects that had been neglected during my 40’s … so I have yet to reignite a formal exercise routine. Although I have just started setting up a weight/exercise room in our new house and hope to start lifting weights again once all of my critical projects have been taken care of (this fall maybe?). Actually I already started lifting weights (boxes and furniture) a month ago for the move .

Anyway, as is already known by many on this forum and nonetheless, being fat is more than just diet, or exercise, or OSA, or depression, or genetics, or some other factor ... it is all connected. Furthermore, fatness and OSA is also an inter-related and complex issue not easily reduced to a simple statistical correlation between the two (IMHO).

[socknitster]

EXACTLY!

I was a scrawny kid to and have similar life experience.

It is true that it is very complex. Can't point to one thing and say, "THAT is it!" But surely apnea sabotages us in the worst way by robbing us of energy and pumping us full of stress hormones that tell our bodies to hold on to every last mg of fat because it might be a famine or something, even though most folks in modern USA have way more than enough to eat.

I'm just so grateful to be only 35 and have to opportunity to get my life back on track. I'll be glad to wear a mask every night/all night if it means I can hold on to this amazing energy!

Jen