The low TSH levels could indicate excess of thyroid
hormones, so your synthroid dose may need to be decreased.
Higher TSH levels (increased beyond the reference range indicate decreased thyroid functioning (hypothyroidism
You can have a T3, and T4 test done as well.
While a low vit. D level (serum 25(OH)D ) is found most commonly in elderly individuals and hospitalized patients (over half of nursing home residents), it is also not uncommon to have healthy young women with low vit. D levels, especially at the end of winter, according to some studies.
Vit D supplementation together with calcium can reduce hip and vertebral fracture risk in women after the menopause.
There is also a condition called secondary hyperparathyroidism
in which there are low PTH levels, that can demineralize bone.
I would suggest contacting your provider and discussing the above options with them.
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Edited by M Javid, MD on 1/19/2010 at 5:36 AM EST