Examination of survey data suggest T3 is positively associated with longevity, but not T4.
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https://www.pnas.org/doi/abs/10.1073/pnas.2308652121
"The hypothalamic–pituitary–thyroid (HPT) axis is fundamental to human biology, exerting central control over energy expenditure and body temperature. However, the consequences of normal physiologic HPT-axis variation in populations without diagnosed thyroid disease are poorly understood. Using nationally representative data from the 2007 to 2012 National Health and Nutrition Examination Survey, we explore relationships with demographic characteristics, longevity, and socio-economic factors. We find much larger variation across age in free T3 than other HPT-axis hormones. T3 and T4 have opposite relationships to mortality: free T3 is inversely related and free T4 is positively related to the likelihood of death. Free T3 and household income are negatively related, particularly at lower incomes. Finally, free T3 among older adults is associated with labor both in terms of unemployment and hours worked. Physiologic TSH/T4 explain only 1.7% of T3 variation, and neither are appreciably correlated to socio-economic outcomes. Taken together, our data suggest an unappreciated complexity of the HPT-axis signaling cascade broadly such that TSH and T4 may not be accurate surrogates of free T3. Furthermore, we find that subclinical variation in the HPT-axis effector hormone T3 is an important and overlooked factor linking socio-economic forces, human biology, and aging."
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@Mulloch94 Fascinating finding, thank you!
It seems to be another proof (besides things like learned helplessness) that poor(er) people aren't "just lazy", but the key ingredient to being more entrepreneurial may also be "the drive" i.e. healthy metabolic (bio)energy.
For a broader audience it would be good to add that formulation of the study's conclusion isn't fully correct. The key issue isn't the level of T4 per se, but its lack of conversion into (free) T3 or even worse conversion of T4 into reverse T3 - which is not mentioned in this research paper together with other factors like low inflammation, low PUFAs, progesterone, and so on, that also influence fT3 levels...
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@Kvirion said in Examination of survey data suggest T3 is positively associated with longevity, but not T4.:
@Mulloch94 Fascinating finding, thank you!
It seems to be another proof (besides things like learned helplessness) that poor(er) people aren't "just lazy", but the key ingredient to being more entrepreneurial may also be "the drive" i.e. healthy metabolic (bio)energy.
Obviously, the formulation of the study's conclusion isn't fully correct. The key issue isn't the level of T4 per se, but its lack of conversion into (free) T3 or even worse conversion of T4 into reverse T3 - which is not mentioned in this research paper together with other factors like low inflammation, low PUFAs, progesterone, and so on, that also influence fT3 levels...
No problem! Yeah I think personally it puts a lot of questions in doubt about standardized IQ measurements for analyzing intelligence too. So called "dumb people" are probably not actually dumb. The brain is a glucose burning organ, and is likely dependent on generous amounts of free T3 to keep running optimally. I mean, Ray has already been saying stuff like that for years, but I find it interesting other researchers are now exploring the relationship between thyroid and aging, drive, and other socioeconomic factors.
Yeah they didn't really get into the specifics I was interested in. I'm fairly certain T4 is rather indifferent in its effects to all of this, simply because free T3 is dependent on good T4 levels, glucose consumption, and liver function. I think probably the most important marker here would've been the ratio of T4 to T3, as a more even one, 3:1 (and under), would indicated good free T3 levels. Whereas higher ones (over 4:1) would indicate a greater amount of reverse T3. The latter may or may not being a factor of diseased livers (PUFA, endotoxin, alcohol use, etc.)
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@Mulloch94 Yeah, agreed. Moreover, IQ studies are also criticized from a statistical point of view.
https://medium.com/incerto/iq-is-largely-a-pseudoscientific-swindle-f131c101ba39the most important marker here would've been the ratio of T4 to T3, as a more even one, 3:1
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@Kvirion said in Examination of survey data suggest T3 is positively associated with longevity, but not T4.:
@Mulloch94 Yeah, agreed. Moreover, IQ studies are also criticized from a statistical point of view.
https://medium.com/incerto/iq-is-largely-a-pseudoscientific-swindle-f131c101ba39the most important marker here would've been the ratio of T4 to T3, as a more even one, 3:1
Interesting read, I agree with a good majority of it. I think in some respects we should take into account IQ tests, but people who suggest its a "gold standard" way of measuring human intelligence are wrong, or biased. At best it's a single marker.
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@Mulloch94 Yeah, the corporate and "rational" (reductionistic) world is probably still in love with a single metric/KPI...
I guess that IQ may be somewhat helpful in measuring the ability to "connect the dots", but intelligence is also about perceiving things "out of the box" (predictive processing), knowing how to make sense of things, not being blinded by ego, etc.
There are also theories about extended cognition i.e. 4E
Fun fact, according to a test done many years ago when I was low in T3, my results in categories of IQ and "processing speed" were exactly on the opposite sides of the Gauss curve, LOL!