The aim of this study is to determine serum sclerostin levels and change in serum sclerostin levels in patients with Vitamin D deficiency treated with calcium and vitamin D.

Healthy premenopausal Patients with Vitamin D deficiency diagnosed and routinely treated with calcium and vitamin D will be included in the study. This is an observational study. The serum sclerostin levels will be measured before and after Vitamin D treatment.

This study is a prospective, observational, single-center study. Ethical approval was obtained from the Institutional Review Board.

This study will be completed with patients with Vitamin D deficiency. An intravenous cannula will be inserted into the antecubital vein. Blood samples will be obtained before and after treatment.

Serum will be collected and will be centrifuged for 15 minutes at 1000Xg within 30 minutes of collection. Aliquots of serum will be added to eppendorf tubes and stored at -20°C.

Serum sclerostin levels will be measured using a Human Sclerostin ELISA kit (Cusabio, Catalog No: CSB-E13146h, Newark, DE, USA). All assays will be performed according to the manufacturer's instructions. The minimum detectable concentration of human sclerostin is typically <0.012 ng/ml. Intra-assay precision is less than 8%.

Inclusion Criteria:

• Premenopausal
• Serum 25(OH)D < 10 ng/mL

Exclusion Criteria:

• Anemia
• Tumor-induced osteomalacia (hypophosphatemia)
• Hypothyroidism
• Hepatic / renal disease
• Primary hyperparathyroidism
• Fibromyalgia
• Polymyalgia rheumatica
• Serum 25(OH)D > 10 ng/mL
• Vitamin D and calcium treatment commenced prior to study participation

Patients with vitamin D deficiency