6 ms·

> The study included 104 severely obese (Body Mass Index (BMI) ≥ 35 kg/m2) men Wouldn't obesity more a factor than a sleep apnea for testosterone levels?

knuthsat 5y ago
The researchers would say that they adjusted the statistics to eliminate that variable but these statistical tricks work only in physics yet somehow they find it acceptable to use for such small N.
- wjnc 5y ago
  Small N point might be true, but “these statistical tricks work only in physics” is false on numerous spots. Things like statistical methods for controlling for certain associations aren’t “tricks” (they use GLM here) and they do not “only” work in physics. Without bringing up the whole replication crisis, there’s a lot of good science in other fields being done with these methods.
  - knuthsat 5y ago
    But what if the relationship with obesity has nonlinearities, how good is this control? There are studies with millions of participants and by controlling for smoking, obesity, they still find increased risk and associations that are still very probably noise.fitting.
    - wjnc 5y ago
      I’m not disagreeing with you that proper statistical research especially in a clinical setting is hard. It was the “tricks” and hint of non-physics : no-science I was responding to. I do think we should give doctors the benefit of the doubt. Just imagine the work involved in research with 100 real patients, let alone larger numbers. Then the next point is: where to get your research subjects. If you want to study non-linearities you’d want both patients and healthy subjects (and ideally people who switch categories). That’s several orders of magnitude more complex to get going. Not every subject gets funding for that scale.
    - potatoman22 5y ago
      Do you mean that the GLM wouldn't properly account for obesity's relationship with testosterone if the two have a nonlinear relationship? Is this something that could be accounted for by splines? I'm still trying to learn this stuff.
Vecr 5y ago
Obstructive Sleep Apnea correlates to obesity and obesity correlates to testosterone levels. Obesity is probably the root cause of both because of the behaviors of adipose tissue (taking up room and trashing your endocrine system, respectively), but I'm not an expert.
- userdro 5y ago
  Would losing the weight increase your testosterone? If you were obese
  - scns 5y ago
    Working out would raise your testosterone levels. Losing weight would happen in the kitchen though. Weight is a bad metric though, since muscles is heavier than fat.
    - bayesian_horse 5y ago
      1 kg of muscles is not heavier than 1 kg of fat. By the way, professional body builders who go to the gym a couple times per week, increase their diet, optimize their diet, etc. are happy to gain 2,5kg of muscle a year. So no, muscle gain has nothing to do with weight gain/loss. Successful diets are a lot faster, and most exercise based programs fail in studies.
      - lottin 5y ago
        An untrained individual who starts training with weights will gain much more than 2.5kg of muscle per year. As the individual accumulates muscle mass the rate of muscle gain will decrease gradually.
        bayesian_horse 5y ago
        Any concrete numbers or sources? I pretty much doubt that it is much more. Or even any more at all. No matter if you are trained or untrained, the number of muscle cells doesn't change. Only the amount of muscle fibers inside the cells changes.
Gibbon1 5y ago
I don't know but I suspect sleep apnea messes up REM sleep. And testosterone is released during REM sleep. Might be a little of both though.
elric 5y ago
The fact that they don't have a control group of normal BMI OSA patients makes me very skeptical regarding any outcomes.
bayesian_horse 5y ago
That would be a stupid way to design a study, right? That's why they compared obese patients who have sleep apnoe to obese patients who don't. No, not everybody who is obese has sleep apnoe.
- OJFord 5y ago
  But then conclude it's the testosterone levels, not the obestiy 'itself' or something more closely related to body fat? I think that's the point. (But maybe testosterone levels are way more tightly correlated than I realise, IANA anything relevant!)
  - bayesian_horse 5y ago
    No such conclusion. The study finds a correlation between sleep apnoe and testosterone levels.
fortran77 5y ago
Probably. People would rather be chained to a machine at night than lose weight.
nerdponx 5y ago
Isn't low testosterone correlated with other, more "general" health conditions anyway? It's certainly an interesting correlation, but I definitely would not try to infer any causality here.

knuthsat 5y ago

The researchers would say that they adjusted the statistics to eliminate that variable but these statistical tricks work only in physics yet somehow they find it acceptable to use for such small N.

wjnc 5y ago
Small N point might be true, but “these statistical tricks work only in physics” is false on numerous spots. Things like statistical methods for controlling for certain associations aren’t “tricks” (they use GLM here) and they do not “only” work in physics. Without bringing up the whole replication crisis, there’s a lot of good science in other fields being done with these methods.
- knuthsat 5y ago
  But what if the relationship with obesity has nonlinearities, how good is this control? There are studies with millions of participants and by controlling for smoking, obesity, they still find increased risk and associations that are still very probably noise.fitting.
  - wjnc 5y ago
    I’m not disagreeing with you that proper statistical research especially in a clinical setting is hard. It was the “tricks” and hint of non-physics : no-science I was responding to. I do think we should give doctors the benefit of the doubt. Just imagine the work involved in research with 100 real patients, let alone larger numbers. Then the next point is: where to get your research subjects. If you want to study non-linearities you’d want both patients and healthy subjects (and ideally people who switch categories). That’s several orders of magnitude more complex to get going. Not every subject gets funding for that scale.
  - potatoman22 5y ago
    Do you mean that the GLM wouldn't properly account for obesity's relationship with testosterone if the two have a nonlinear relationship? Is this something that could be accounted for by splines? I'm still trying to learn this stuff.

Vecr 5y ago

Obstructive Sleep Apnea correlates to obesity and obesity correlates to testosterone levels. Obesity is probably the root cause of both because of the behaviors of adipose tissue (taking up room and trashing your endocrine system, respectively), but I'm not an expert.

userdro 5y ago
Would losing the weight increase your testosterone? If you were obese
- scns 5y ago
  Working out would raise your testosterone levels. Losing weight would happen in the kitchen though. Weight is a bad metric though, since muscles is heavier than fat.
  - bayesian_horse 5y ago
    1 kg of muscles is not heavier than 1 kg of fat. By the way, professional body builders who go to the gym a couple times per week, increase their diet, optimize their diet, etc. are happy to gain 2,5kg of muscle a year. So no, muscle gain has nothing to do with weight gain/loss. Successful diets are a lot faster, and most exercise based programs fail in studies.
    - lottin 5y ago
      An untrained individual who starts training with weights will gain much more than 2.5kg of muscle per year. As the individual accumulates muscle mass the rate of muscle gain will decrease gradually.
      - bayesian_horse 5y ago
        Any concrete numbers or sources? I pretty much doubt that it is much more. Or even any more at all. No matter if you are trained or untrained, the number of muscle cells doesn't change. Only the amount of muscle fibers inside the cells changes.

Gibbon1 5y ago

I don't know but I suspect sleep apnea messes up REM sleep. And testosterone is released during REM sleep. Might be a little of both though.

elric 5y ago

The fact that they don't have a control group of normal BMI OSA patients makes me very skeptical regarding any outcomes.

bayesian_horse 5y ago

That would be a stupid way to design a study, right? That's why they compared obese patients who have sleep apnoe to obese patients who don't. No, not everybody who is obese has sleep apnoe.

OJFord 5y ago
But then conclude it's the testosterone levels, not the obestiy 'itself' or something more closely related to body fat? I think that's the point. (But maybe testosterone levels are way more tightly correlated than I realise, IANA anything relevant!)
- bayesian_horse 5y ago
  No such conclusion. The study finds a correlation between sleep apnoe and testosterone levels.

fortran77 5y ago

Probably. People would rather be chained to a machine at night than lose weight.

nerdponx 5y ago

Isn't low testosterone correlated with other, more "general" health conditions anyway? It's certainly an interesting correlation, but I definitely would not try to infer any causality here.