Status of vitamin D levels in hypothyroid patients and its associations with TSH, T3 and T4 in north Indian population of Meerut, a cross sectional study

Vitamin D deficiency has been identified as a risk factor for several autoimmune diseases, cancers, atherosclerosis, etc. Its deficiency has also been shown to be associated with hypothyroidism with inconclusive results. The present study aims to explore the association of vitamin D deficiency with hypothyroidism.

This is a cross sectional study conducted in the department of biochemistry Subharti Medical College, Meerut. A total of 152 clinically suspected hypothyroid subjects in the age group of 20–60 years, from both sexes attending Medicine OPD were included in the study.

All the patients were subjected to complete general physical and systemic examination and findings noted. The vitamin D, T3, T4 and TSH were measured in all by enzyme linked fluorescence assay (ELFA) in Vidas PC auto-analyzer from Biomerieux. The patients were then categorized into euthyroid (TSH=0.25–5μIU/ml), subclinical hypothyroid (TSH >5–7μIU/ml) and overt hypothyroid (TSH>7μIU/ml) based on serum TSH cut off values. The patients were also defined as vitamin D sufficient (>30ng/ml), insufficient (20-30ng/ml) and deficient (<20ng/ml) based upon the recent consensus on vitamin D classification.

The mean value of vitamin D in subclinical hypothyroid (16.73±12.46 ng/ml) and overt hypothyroid (13.23±10.08 ng/ml) were significantly lower than the euthyroid (29.07±19.01 ng/ml) with P value<0.05. Pearson's correlation analysis between vitamin D and TSH (r=-0.314, P<0.01) have shown a significant negative correlation.

Vitamin D deficiency negatively correlates with TSH. Thus we suggest vitamin D supplementation to all hypothyroid patients.