PTH and metastatic malignant neoplasm in the lymph nodes: Various factors were identified as contributors to postoperative hypocalcemia, including lymph node metastasis (odds ratio [OR] = 2.6; P < 0.05), total thyroidectomy (OR = 8.0; P < 0.01), diminished parathyroid hormone (PTH) levels (OR = 12.6; P < 0.001), and reduced 25-hydroxyvitamin D3 (25[OH]D3) levels (P < 0.01).