Posted by Larry Hoover on February 6, 2006, at 13:28:46
In reply to Study: Mild Hypo-Thyroid Should not be Treated, posted by jrbecker on January 16, 2006, at 9:33:41
General comments....
The treated group was given a fairly substantial dose of thyroxine for the first 12 weeks, but then they say that doses were adjusted based on TSH levels. That may be precisely the problem. The patients had nine months to return to their pre-intervention levels. If the individual with hypothyroid is not producing sufficient T4 in the first place, despite TSH levels that are above "normal", then supplementing with T4 is still going to lead to a similar hypo condition because of homeostatic regulation in the thyroid gland....unless the dose is sufficiently high to suppress TSH below 0.5 or so. At that point, supplementation becomes the dominant source of thyroid hormone, as it is out of range for the *individual's* thyroid settings.
Also, the treated subjects were only given the hormone T4. There may be hypothyroid effects arising from inefficient deiodination of T4 to T3 (which occurs in various organs, not just in the liver), which would be completely unaffected by supplementing with T4.
The treated participants should have been treated to an endpoint determined by free T3, IMHO. Free T4 would obviously be higher than normal, due to oral intake of unbound hormone.
I'm not convinced this study showed us anything useful. I'm not convinced that any conclusions can be reached from a null finding. They did not control for T4/T3 conversion. They did not control for thyroid globbulin variability (thyroid binding protein). They did not titrate individual dosing to an endpoint that differs from "conventional" measures of thyroid function, which may be precisely the point of suffering for those not helped by doctors of this mindset.
It would be useful to see the study itself, and take a look see at the data......that is a limitation for me.
My conclusion: Conventional thyroid measures do not correlate with patient symptoms. Conventional thyroid treatment has endpoints not correlated with symptom remission.
Lar
poster:Larry Hoover
thread:600083
URL: http://www.dr-bob.org/babble/health/20060202/msgs/606907.html