Evaluation of Vitamin D3 as a diagnostic marker in hypothyroidism

Aim: To investigate the role of serum vitamin D3 in the pathogenesis and diagnosis for hypothyroidism..

Materials and Methods: Cross-sectional study was conducted at the Outpatient Analytics Center of Al-Nokhba and Al-Sadder Teaching Hospital, Najaf, Iraq, between October 2021 and February 2022. A total of two groups, Group I (49 hypothyroid patients; mean age 47.69±8.961 years) and Group II (49 healthy controls; mean age 47.43±9.89 years), were included. The estimation of serum T3, T4, TSH, calcium, and 25(OH) vitamin D levels was performed by GP1100 immunofluorescence quantitative analyzer. Serum Calcium levels were determined by the spectrophotometric method.

Results: Hypothyroid patients had much lower serum 25(OH) vitamin D levels; mean value was 12.45±0.95 ng/ml whereas for controls it was 31.35±0.87 ng/ml (P<0.000). T3, T4, and calcium levels were also significantly low in the hypothyroid patients, as opposed to the high levels of TSH. The sensitivity and specificity of vitamin D3 in the diagnosis of hypothyroidism is 71% and 65% respectively.

Conclusions: This study underlines a strong association between hypothyroidism and low serum levels of vitamin D. The results support the notion that, in fact, vitamin D deficiency may be involved in the pathophysiology of hypothyroidism, thus indicating the significance of monitoring and correcting the status of this vitamin in such patients. Further studies should be directed to the casual pathways and therapeutic benefits of vitamin D supplementation.