SERUM VITAMIN D LEVELS IN EUTHYROID AND HYPOTHYROID FEMALES VISITING A TERTIARY CARE CENTER OF WESTERN NEPAL

Abstract

Background: Thyroid function and vitamin D levels may be intricately related. The purpose of the current study was to investigate the relationship between thyroid hormones and vitamin D levels in females attending a tertiary care center in western Nepal.

Methods: This hospital-based cross-sectional study enrolled 300 women advised to get a thyroid function test (TFT) were included in the study population. They were grouped as euthyroid and hypothyroid based on the TFT status and their serum vitamin D concentrations were measured. Vitamin D levels were classified as normal, deficient, and insufficient using the standard criteria. Statistical tests like Chi-square analysis, Mann-Whitney U test, Kruskal Wallis test, and Spearman’s correlation analysis were performed. Finally, a multiple linear regression analysis was done to adjust for the effects of confounding variables.

Results: Majority of the study population (n=214, 71%) had insufficient serum vitamin D levels. The median Vitamin D levels were significantly lower in hypothyroid group as compared to the euthyroid group (16.88 vs. 25.01 ng/ml, p <0.001). Similarly, serum Vitamin D levels were negatively associated with obesity, winter and spring seasons, and vegetarian diet. After adjustment for the confounders, the Vitamin D levels were significantly lower in hypothyroid population than the euthyroid group (P<0.001).

Conclusions: In conclusion, majority of our study participants had insufficient vitamin D, whose concentration further dropped with decreasing thyroid hormone levels. This could have potentially adverse clinical implications.