Endocrine Regulations Vol.49, No.2, p.84-90, 2015

Objective. Subclinical hypothyroidism and vitamin D deficiency are common. The diastolic function of patients with both subclinical hypothyroidism and vitamin D deficiency remains unknown. This study aimed to investigate diastolic dysfunction in patients with both subclinical hypothyroidism and vitamin D deficiency.
Subjects and Methods. This study included 254 patients. All patients underwent standard Doppler echocardiography. Patients who had risk factors for diastolic dysfunction or had used L-thyroxine and vitamin D within the previous 3 months were excluded. Vitamin D deficiency was defined as a 25-OH-vitamin D level lower than 20 ng/ml, and vitamin D sufficiency was defined as a 25-OH-vitamin D level ≥30 ng/ml. Subclinical hypothyroidism was defined as a TSH level of 4.5-10 mU/l when the free T4 concentration was normal.
Results. T

he patients were divided into 4 groups. Group 1 (n=71) included patients with subclinical hypothyroidism and vitamin D deficiency; Group 2 (n=66) included patients with subclinical hypothyroidism and vitamin D sufficiency; Group 3 (n=65) included euthyroid patients with vitamin D deficiency; and Group 4 (n=52) included euthyroid patients with vitamin D sufficiency. LAVI (31.3±3.2, 28.7±3.0, 28.4±3.4, and 27.9±3.9; p<0.001) and E/E’ values (11.2±2.7, 8.9±2.7, 9.1±2.9, 8.8±2.5; p<0.001) were significantly higher in Group 1 than in Groups 2, 3 and 4. E’ values were significantly lower in Group 1 than in Groups 2, 3 and 4.

Conclusion. The coexistence of subclinical hypothyroidism with vitamin D deficiency can lead to further deterioration in the LV diastolic function via the regulation of intracellular calcium and induction of inflammatory activity. Therefore, close follow-up of the diastolic functions of these patients could be beneficial.