Correlation Between Vitamin D and TSH Levels in Healthy Controls and Individuals with Hypothyroidism According to Age and Sex.

BACKGROUND

Elevated levels of circulating 25-hydroxyvitamin D (25 (OH) D) are correlated with reduced levels of circulating thyroid-stimulating hormone (TSH).

OBJECTIVE

The aim of this study was to evaluate the relationship between vitamin D and circulating TSH levels based on sex and age, with a focus on thyroid autoimmunity and thyroid hormone levels.

METHODS

Fifty samples were obtained from patients with hypothyroidism (Hashimoto's thyroiditis, HT) aged 18-59 years (49.4% men, 50.6% women). The samples were tested for serum vitamin D and TSH levels using the enzyme-linked immunosorbent assay.

RESULTS

The mean TSH level in the HT group (5.97 ± 0.18) was significantly higher than that in the control group (1.61 ± 0.1) (P < 0.001). Conversely, the mean vitamin D level was significantly lower in the HT group (40.5 ± 0.72) than in the control group (57.3 ± 0.72) (P < 0.001). Differences based on sex were not statistically significant (P = 0.096). Similarly, no differences were observed in age group distributions. Overall, moderate and strong positive correlations were observed in the control (r = 0.4767, P = 0.0009) and HT (r = 0.7493, P < 0.0001) groups, respectively.

CONCLUSION

This study showed a negative correlation between serum vitamin D and TSH levels in both healthy controls and patients with HT, regardless of age and sex.