"Higher Metabolism, Temperature And Pulse And Lower TSH Associated With Higher Mortality"

[Ahanu]

If they didnt measure Cortisol, Progesteron etc then it makes no sense to use this Baltimore study as an argument against peat claims. But i am sure this had been said allready a hundred Times.

 

[Waynish]

Are we assuming that BMR and TSH values are more tightly coupled than they really are?
No need to have any fear here: criticizing good ideas only makes them stronger, right?

 

[Giraffe]

BMR was [...] expressed as kcal/m2/h, based on DuBois’s equation to estimate the body surface area.

Body weight (or fat-free mass) should be used to make BMR comparable. For the same BMR expressed in kcal/kg, the BMR expressed in kcal/m² is estimated higher in shorter men and in those with higher weight.

.....

In this FAO paper the use of the surface area as a unit of size is criticized.

Body weight is the most important factor in modifying BMR but its effect will vary with the age group of the individual.

[...] there are two theoretical considerations which somewhat inhibit the acceptance of surface area as the unit of size. Firstly, as mentioned above, if surface area determines the heat loss from the body, the level of basal metabolism must depend upon the surface area, whereas, in fact, basal metabolism is a function of the metabolic activity (or oxygen consumption) of all the separate active tissues of the body and is dependent on the relative mass of these tissues.

Secondly, surface area is not a reference which is measured. It is calculated from height and weight, probably using the formula of Du Bois & Du Bois (1916), and has an unknown error attached to its use for any given individual [...] Body weight, on the other hand, if it can be shown to be an acceptable reference, is one of the easiest and most accurate of all biological measurements.

I played a bit with the DuBois equation. I used the simple estimation BMR = 25 x body mass to estimate either the BMR or the BMR (kg). Then I varied the body surface area by changing the height or the weight. Here is the result:

Mitchell, Strydom, van Graan & vander Walt (1971) found that the Du Bois formula consistently underestimated the surface area of 237 young adult males relative to the true area as measured by a photometric technique.

[...] the smaller the man, the larger the discrepancy. [source]

These effects work all in the same direction.

 

[Giraffe]

Can somebody explain this ? The older people had higher BMR.

The ones who died were older at first visit. They had a higher BMI. Despite their shorter follow-up time they had more visits per participant....

Is the entire study not skewed by those age differences?

:10:

 

[Queequeg]

If they didnt measure Cortisol, Progesteron etc then it makes no sense to use this Baltimore study as an argument against peat claims. But i am sure this had been said allready a hundred Times.

The people with major adrenal issues where excluded.
“Participants with known or suspected thyroid or adrenal dysfunction, as evidenced by history, drug use, or physical examination, were excluded. “

I would guess that the percentage of people with higher metabolisms and undiagnosed high cortisol is fairly low since most people don’t have chronically jacked cortisol levels over a 40 year period. I don’t think that the small numbers would change the study's conclusions given such a dramatic increase in mortality due to higher metabolism.

 

[Queequeg]

Body weight (or fat-free mass) should be used to make BMR comparable. For the same BMR expressed in kcal/kg, the BMR expressed in kcal/m² is estimated higher in shorter men and in those with higher weight.

In this FAO paper the use of the surface area as a unit of size is criticized.
I played a bit with the DuBois equation. I used the simple estimation BMR = 25 x body mass to estimate either the BMR or the BMR (kg). Then I varied the body surface area by changing the height or the weight. Here is the result:
These effects work all in the same direction.

A full read of the paper you quoted from leaves me with a very different conclusion than yours. Expressing metabolic rate is kcal/m2/hour is commonly done and there is no evidence that expressing it in terms of mass is better. I think the paper is saying that it is easier to just use mass as surface area is overkill. Both methods have their pros and cons.

BMR is expressed as energy per unit of body size per unit of time. In the past, these units have frequently been kcal/sq.m. of surface area/hour. Whether or not these are the most appropriate units is a matter for considerable controversy. It should be noted immediately that there is no unanimity on the proper unit for body size

“The conclusion must surely be that, at the present time, there are no means available to us to be precise in our estimate of BMR, other than in a completely spurious manner. It is quite astonishing to consider the probably futile efforts which have been exerted in the examination, of the data on man, of weight, weight to the power 0.7, 0.73 or 0.75, and surface area, as the unit of preference when there is clearly almost no difference between any of them, all of them are useful only in a very imperfect fashion, and one of them - weight - is easy, accurate and simple to measure and to utilize”

“A table has been formulated to allow prediction of BMR in individuals of any age or of a range of body weights. Body weight is the most important factor in modifying BMR but its effect will vary with the age group of the individual. The use of this table is certainly open to some error but the variability of the published data is such that it is unlikely that more complex methods of calculating BMR offer any increased accuracy and the present table has the great advantage of being very easy to apply.”

IMO he is not saying that utilizing mass is more accurate than using surface area but rather that using surface area, which takes into account both mass and body shape, would be overkill as there is so much other variability in the assessment of energy use. In other words just using the biggest driver of BMR, body weight, is good enough and that more complicated method such as surface area are not justified. This is just one researcher's opinion and others have different opinions.

In any case I think the difference in the way BMR is expressed doesn’t matter in the least as the differences are well within the margin of error of BMR. Also in a sample size of 1200 people, any outliers that one method or the other doesn’t properly calculate would not make a difference in the final conclusions as their effect would be so small.

From the Baltimore study:
“The risk of death increased significantly as a squared function of BMR, expressed either as kcal/m2/h or kcal/kg/h, and independent of age, date of visit, race, weight, and BMI (Table 3, Model 1).”

 

[Ahanu]

The people with major adrenal issues where excluded.
“Participants with known or suspected thyroid or adrenal dysfunction, as evidenced by history, drug use, or physical examination, were excluded. “

I would guess that the percentage of people with higher metabolisms and undiagnosed high cortisol is fairly low since most people don’t have chronically jacked cortisol levels over a 40 year period. I don’t think that the small numbers would change the study's conclusions given such a dramatic increase in mortality due to higher metabolism.

I think peat considers the medical classification for thyroid dysfunction not excact. He thinks there are much more people with thyroid dysfunction than recocnised.

 

[Queequeg]

I think peat considers the medical classification for thyroid dysfunction not excact. He thinks there are much more people with thyroid dysfunction than recocnised.

true but you typically don't want to do studies on only people in perfect health with all of their numbers in the optimal range. You want to look at the general population and exclude only those with really bad health problems.

 

[Queequeg]

Drareg said: ↑" Is the entire study not skewed by those age differences?"
:10:

I think those judges were paid off. Of course the differences in age are taken into account. Otherwise the findings would be “Increased age is a Risk Factor for Mortality.” They measured mortality using “excess mortality.” This is the difference between the expected death rate and the observed death rate. The expected death rates take into account the age of each participant plus many other covariates:

Model 1 was adjusted for age, date of visit, race, weight, and BMI. Model 2 was also adjusted for smoking, and Model 3 was adjusted for all covariates of Model 2 plus total physical activity, creatinine excretion, muscle strength, and white blood cell count.

I think a better question to ask is why Drareg and you are so intent on knocking down every study that contradicts Ray. What if we maintain an open mind, subject all studies to equal scrutiny, and go wherever the evidence leads us

 

[Ahanu]

What if we maintain an open mind, subject all studies to equal scrutiny, and go wherever the evidence leads us

I belive that is what peat is doing. It is just not that simple as some would like it to be.

 

[Drareg]

@Drareg So you still haven’t found any studies to support your faith based ideology. As for your last rant, I hope you were able to get out some of the frustrations you must be feeling. The sheer amount of anger and scorn coming from you is only matched by your lack of understanding about clinical research. You say I am filled with “deluded hubris fuelled mania” and then proceed to try to tear down one of the most respected and well funded studies on aging in the world. Why don't you post some of your studies so we can all learn how it should be done. Instead of trying to discredit it, you could try to actually learn something from it. Clinical studies rarely get any better than this. Baltimore Longitudinal Study of Aging |

Though you didn't get to use your favorite word "Strawman" until the very end, I am glad you wasted no time in creating yet another Strawman of your own.

This is what I wrote:
See the difference?

I appreciate the time you must have spent combing through the study, searching out potential flaws, typing up carefully considered arguments and thinking up all those multi adjective insults. With that in mind, you can rest assured that I will give your post and all of its many questions all the due consideration that they deserve. now that is priceless

We are still waiting for your research which categorically proves your point,you dont read the entire studies you are posting,your attempting to use abstracts as contrarian to Peats view while trying to create the context of the argument,you change the argument when you are cornered,not one point have you addressed in the posts I have made on your studies,your lazy argument style is essentially why?why?why?

Your claim of strawman from me was addressed and highlighted as your manic projections and not a strawman,you however are throwing labels of strawman again with no quotes or points countering it,this is your form throughout,you are playing to crowd with use of these terms to save face,you address no points put to you.


If the Baltimore study is the best "science" has it's understandable why the majority of the establishment is a mess and curing nothing. Even useless outdated studies can have some tidbits that can be gleaned from them.
The clinical research you quote is based on leaps of faith and perceptions ,it's essentially a religious organisation just like the peer review system. These organisations would suit you,there full of hubris and authorities terms like "peer reviewed well respected scientific study".
The researchers need to publish to get paid and stay in contention for grants and jobs,this tilts tables.

Your ignorance to the TSH levels arguments ongoing is another example of your hubris.

 

[Drareg]

I think peat considers the medical classification for thyroid dysfunction not excact. He thinks there are much more people with thyroid dysfunction than recocnised.

I seen your earlier posts in this thread and you made too much sense hence why you were ignored,the other posters are creating a strawman,your supposed to argue their mania fuelled hubris filled projections.

 

[Drareg]

I think those judges were paid off. Of course the differences in age are taken into account. Otherwise the findings would be “Increased age is a Risk Factor for Mortality.” They measured mortality using “excess mortality.” This is the difference between the expected death rate and the observed death rate. The expected death rates take into account the age of each participant plus many other covariates:

I think a better question to ask is why Drareg and you are so intent on knocking down every study that contradicts Ray. What if we maintain an open mind, subject all studies to equal scrutiny, and go wherever the evidence leads us

Yet they won't publish the individual ages.
Please clarify how they come to the conclusion of expected death rate.
Please clarify your understanding of excess mortality.

Are your trying to say that survivors were the same age as those who died even though the table has over 10 years mean age difference which means it's possible there is more of an age gap if we look at individual results.

"I think a better question to ask is why Drareg and you are so intent on knocking down every study that contradicts Ray. What if we maintain an open mind, subject all studies to equal scrutiny, and go wherever the evidence leads us[/QUOTE]"
More strawman and mania fuelled hyperbole in claiming we are knocking down every study that contradicts Peat,you then ask in the next sentence if we can subject studies to equal scrutiny while complaining we subjected yours to scrutiny,your pickled with hubris and delusion,keep in mind this is another one of your many posts where you use a tone of superiority/hubris with terms that call to authority while still dodging points put to you.

With the above quote in mind I think the better question to ask is why you can't provide categoric proof of Peats ideas being wrong,you have continuously dodging the points put to you about the flawed studies you posted.
You have an unquestioning dogmatic following of random cherry picked studies,studies full of flaws yet you have the hubris to ignore multiple posters pointing out flaws in your ever changing argument.

 

[Drareg]

true but you typically don't want to do studies on only people in perfect health with all of their numbers in the optimal range. You want to look at the general population and exclude only those with really bad health problems.

Another response filled with trite nonsense.
Define "optimal range" in relation to TSH ? Have you read any of the information posted in this thread on the ongoing debates with TSH?
Define perfect health?

 

[Drareg]

The ones who died were older at first visit. They had a higher BMI. Despite their shorter follow-up time they had more visits per participant....


:10:

Exactly,It was the ages in particular I was getting at.

 

[Drareg]

The people with major adrenal issues where excluded.
“Participants with known or suspected thyroid or adrenal dysfunction, as evidenced by history, drug use, or physical examination, were excluded. “

I would guess that the percentage of people with higher metabolisms and undiagnosed high cortisol is fairly low since most people don’t have chronically jacked cortisol levels over a 40 year period. I don’t think that the small numbers would change the study's conclusions given such a dramatic increase in mortality due to higher metabolism.

Your response to the question is a strawman. Notice how @Ahanu also used the term etc.
I have pointed this quote before,adrenal dysfunction and thyroid were only checked,saying, "as evidenced by" ,is how they checked the former.

Keep in mind the quote at the end of study and on top of that keep in mind TSH methods have since improved hence the ongoing arguments within the establishments about TSH levels--
"However, we caution the readers about the difficulty of detecting early thyroid dysfunction based only on physical examination. During 1958–1982, thyroid-stimulating hormone (TSH) radioimmunoassay or triiodothyronine (T3) determinations were not available
for the BLSA participants, and later they were measured only in a subgroup."

You have been responding throughout the thread in this manner,you are a charlatan.

 

[Drareg]

The ones who died were older at first visit. They had a higher BMI. Despite their shorter follow-up time they had more visits per participant....


:10:

Important not to forget the fasting for 12 hours and the effects this would have on mobilising stress hormones.

 

[tara]

In other words, TSH is useful to understand the gap between where your hypothalamus wants the overall metabolism at and where it actually is. If TSH is high, your hypothalamus wants to raise metabolism from where it currently is, and if it is very low, it wants to decrease metabolism relative to where it currently is. But TSH by itself cannot give much info as to where to metabolism is at relative to a standard.

This is how I understand it too.
That there are various conditions in which the body down-regulates thyroid function, often for reasons that have had evolutionary importance in the past, such as surviving famines etc, which can also apply under current conditions eg severe restrictive 'dieting' etc.

 

[tara]

Important not to forget the fasting for 12 hours and the effects this would have on mobilising stress hormones.

Indeed. Some of the people with poorer glycogen stores may be more likely to have stress-elevated metabolism in the morning fasted state than some of the healthier ones with stronger stores.

[eta:] And one of the ways to help distinguish stress/thyroid metabolism is to see whether temps go up or down from fasting before breakfast to a while after when breakfast digestion is well underway.

 

[Queequeg]

@Drareg Seriously, can you tone down the temper tantrums? You obviously have too much anger in you to discuss anything civilly. You just make up all sorts of crap to charge me with as if just saying it over and over will make them true. Your questions only show that you really don’t understand what you are reading, and given your attitude, I am not about to try to answer your questions and explain every term or method to you. Google proportional hazards model if you want to understand how excess mortality is calculated and how age is factored into their analysis. If you spent a little more time studying the paper and less time accusing me of hubris, mania and strawmen you would have many answers to your questions. As for why they didn’t provide the brain sizes of each of the 1,200 subjects, you would probably have to write the authors and ask them as I am sure no one has thought to ask that one before.