PTH and major depressive disorder: BDI-II - Beck Depression Inventory-II, Vit D-Vitamin D, PTH- Parathyroid hormone, 25(OH)D-25 - Hydroxyvitamin D, ICD-9 - International Classification of Diseases, Ninth Revision, GDS- Geriatric Depression Scale, VDD- Vitamin D Deficiency, CES-D - Center for Epidemiological Studies-Depression Scale, EPDS- Edinburgh Postnatal Depression Scale, PPD- Postpartum depression, NA- not available