I came across an interesting study in my weekly alerts from pubmed I have setup, that I should might be useful to some here and I couldn't see it already linked.
"Low bone mineral density is related to high physiological levels offT4 not to TSH levels below lower reference range."
There's full text available - in Spanish? and English from what I can see - but I can only see it available for purchase for a pricy sum or via an instituion login. Anyhow, the summary etc is below. Please forgive the all caps but this is how it was written on their site:
"OBJECTIVETO DETERMINE WHETHER THYROID HORMONE (FT4) RATHER THAN THYROTROPHIN (TSH) IS DIRECTLY RELATED TO BONE MINERAL DENSITY (BMD).DESIGNCROSS-SECTIONAL POPULATION COHORT STUDY OF PERIMENOPAUSAL WOMEN.METHODSOF A SAMPLE OF 6846 PERIMENOPAUSAL DUTCH WOMEN WHO PARTICIPATED IN AN OSTEOPOROSIS SCREENING PROGRAM, A COHORT OF 2584 WAS RANDOMLY SELECTED FOR ASSESSMENT OF THYROID FUNCTION (TSH, FT4 AND THYROID PEROXIDASE ANTIBODIES, TPO-AB). TPO-AB POSITIVE WOMEN, WOMEN WITH A PREVIOUS HISTORY OF THYROID DYSFUNCTION, OVERT THYROID DISEASE, SUBCLINICAL HYPOTHYROIDISM, OSTEOPOROSIS OR BILATERAL OOPHORECTOMY, AND THOSE RECEIVING THYROID HORMONE OR HORMONE REPLACEMENT THERAPY, WERE EXCLUDED. OF 1477 ELIGIBLE WOMEN, 1426 HAD TSH AND FT4 WITHIN THE REFERENCE RANGE AND 51 HAD LOW OR UNDETECTABLE SERUM TSH. BMD WAS MEASURED AT THE LUMBAR SPINE AND LOW BMD WAS DEFINED AS 0.937G/CM2.RESULTSTHE MEAN BMD IN THE 51 WOMEN WITH LOW OR UNDETECTABLE SERUM TSH WAS 0.984 G/CM2 COMPARED TO 1.001 G/CM2 IN THE REMAINING 1426 (T=0.94, P=0.35). 33% OF WOMEN WITH LOW OR UNDETECTABLE SERUM TSH HAD LOW BMD COMPARED TO 34% IN 1426 EUTHYROID WOMEN. HIGH FT4 BUT NOT LOW TSH IN EUTHYROID WOMEN WAS RELATED TO LOW BMD BY MULTIPLE LOGISTIC REGRESSION CORRECTED FOR AGE, BMI AND SMOKING (OR: 1.30, 95% CI 1.02-1.69).ConclusionsHigher FT4 levels within the normal reference range but not low or undetectable serum TSH were independently related to decreased BMD at lumbar spine in perimenopausal women."