| Abstract
Pupose: Although there are reports of vitamin D (VitD) insufficiency in immune-mediated
hypothyroidism, an association between VitD and thyroid-stimulating hormone (TSH)
levels has yet to be shown. We aim to examine VitD and TSH levels among
postmenopausal women, as both conditions are more prevalent in elderly women.
Methods: The clinic records of postmenopausal women during their routine maintenance
visits were reviewed. All patients were examined for the symptoms related to thyroid
function and osteoporosis. Participants were divided into three subgroups according to their
TSH levels (below <0.5 mIU/L, 0.51-4.0 mIU/L and >4.0 mIU/L). Patient characteristics
and VitD levels were compared between these subgroups. Multivariate linear regression
model was constructed using serum VitD and serum TSH as the dependent variables to
identify factors independently associated with these laboratory values.
Results: Two-hundred and nighty nine postmenopausal women were included. Average age
was 62.2±7.5 years old. VitD was insufficient (10-30 ng/mL) in 12.0% and deficient (<10
ng/mL) in 60.9% of the participants. In 11.3%, TSH was low and in 7.6% of women, TSH
was high, while the remaining 80.1%, had normal TSH levels. Subjects with low TSH had
significantly higher VitD concentrations (34.2±29.1 ng/mL) compared to the other two
groups (P-value: 0.039). In multivariate regression analysis, TSH was not a contributing
factor, as age was the only significant predictor of VitD levels. Meanwhile, no predictor
(including age and VitD) was identified for TSH levels in linear regression analysis.
Conclusion: Age was the only independent predictor of serum VitD in this study
population. Though suppressed TSH was associated with higher VitD levels, the association
was not linear between TSH and VitD in postmenopausal women. |