Research - TSH above 2 possibly abnormal and is associated with high cortisol

[Saggyuk]

Hey guys

Just found this which found that a TSH above 2 is significantly related with high cortisol in healthy men and women and therefore conclude that TSH above 2 should possibly be deemed abnormal. There was no correlation with high cortisol and TSH under two nor with T3/T4 levels.

I expect this has already been posted on here before as from 2012 but thought it interesting and worth posting again. It does discuss what this could mean for the normal TSH ranges used and diagnosis of subclinical hypothyroidism and that metabolic stress and therefore symptoms are indicated at a far lower level than the upper range used today - which we already know lol. But it also highlights that increased TSH associated with thyroid failure causes high cortisol but in contrast adrenal function abnormalities that causes high cortisol suppresses the TSH and therefore causes a thyroid problem. I knew the function of each could impact the other but was unaware that it might be this simple to determine which of the two is the initial problem - well unless you have failure of both I suppose lol??

I'm still trying to get to bottom of high cortisol and haven't been able to get TSH under two for a 2-3 years seemingly due to no T4 so maybe this might be the cause of my high cortisol if the above applies. However, I seem to have worse symptoms relating to high cortisol if I do increase my thyroid meds even though this problem is now resolved - maybe just haven't pushed it far enough for long enough yet??

I suppose it needs to be done on larger scale with better methods too.

Abstract

Background

Recent attention has been given to subclinical hypothyroidism, defined as an elevation of TSH (4.5-10 uIU/L) with T4 and T3 levels still within the normal range. Controversy exists about the proper lower limit of TSH that defines patients in the subclinical hypothyroidism range and about if/when subclinical hypothyroidism should be treated. Additional data are needed to examine the relationship between markers of thyroid function in the subclinical hypothyroidism range, biomarkers of health and ultimately health outcomes.

Objective

We aimed to assess the relationship between serum TSH levels in the 0.5-10 uIU/L range and serum cortisol in a cohort of healthy young men and women without clinical evidence of hypothyroidism. Based on data in frank hypothyroidism, we hypothesized that serum TSH levels would be positively correlated with serum cortisol levels, suggesting derangement of the cortisol axis even in subclinical hypothyroidism.

Methods

We conducted a cross sectional study in 54 healthy, young (mean 20.98 +/− 0.37 yrs) men (19) and women (35). Lab sessions took place at 1300 hrs where blood was drawn via indwelling catheter for later assessment of basal serum TSH, free T3, free T4, and cortisol levels.

Results

All but 1 participant had free T3 levels within the normal reference intervals; free T4 levels for all participants were within the normal reference intervals. Linear regression modeling revealed that TSH levels in the 0.5-10 uIU/L were significantly and positively correlated with cortisol levels. This positive TSH-cortisol relationship was maintained below the accepted 4.5 uIU/L subclinical hypothyroid cutoff. Separate regression analyses conducted by systematically dropping the TSH cutoff by 0.50 uIU/L revealed that the TSH-cortisol relationship was maintained for TSH levels (uIU/L) ≤4.0, ≤3.5, ≤3.0, and ≤2.5 but not ≤2.0. Linear regression modeling did not reveal a relationship between free T3 or free T4 levels and cortisol levels.

Conclusions

Results suggest a positive relationship between TSH and cortisol in apparently healthy young individuals. In as much as this relationship may herald a pathologic disorder, these preliminary results suggest that TSH levels > 2.0 uIU/L may be abnormal. Future research should address this hypothesis further, for instance through an intervention study.

[silverfox7]

Sadly many doctors are stuck in a time warp plus to be fair they don't have time to keep up to date. Plus you only have to look at the lab ranges to know they should be narrower. But your comments have reminded me of a book I did some illustrations for. it was ranges for medical students. I must have a look what he said about the thyroid! I left work about 32 years ago so the book is older than that! Plus I didn't have a thyroid problem then so it wouldn't have meant much!

Never shirk at putting in things people may already be familiar with. Sometime old stagers need a reminder plus I imagine there is a good turnover of new members.