title: Effects of 25-hydroxyvitamin D3 therapy on bone turnover markers and PTH levels in postmenopausal osteoporotic women treated with alendronate.
abstract: OBJECTIVE
  Our objective was to know the extent to which a fall in bone turnover markers is influenced by serum 25-hydroxyvitamin D (25OHD) levels in patients on alendronate (ALN) treatment.
  
  
  METHODS
  A total of 140 postmenopausal osteoporotic women were randomized to receive either ALN or ALN plus 25OHD(3) (ALN+VitD) over a 3-month period. Serum 25OHD, PTH, C-terminal telopeptide of type I collagen (CTX), and amino-terminal propeptide of type I collagen (P1NP) were measured at baseline and at the end of the 3 months.
  
  
  RESULTS
  25OHD rose four times above baseline levels in the ALN+VitD group, whereas no changes were seen in the ALN group. Administering ALN resulted in a significant decline in both serum CTX (53 ± 24%) and P1NP (46 ± 19%). After ALN+VitD, the fall in CTX amounted to 61 ± 20% (P = 0.06 compared with ALN) and P1NP to 50 ± 23% (P = 0.35). When patients were divided into those below and above 20 ng/ml of baseline serum 25OHD, in those below, CTX decreased by 48 ± 26% in the ALN group and by 61 ± 17% in the ALN+VitD group (P = 0.015). For P1NP, the corresponding figures were 43 ± 20 and 50 ± 23% (P = 0.2). In patients above 20 ng/ml, no differences were seen regarding CTX (58 ± 21% decrease in the ALN group and 60 ± 23% in the ALN+VitD group; P = 0.7) or P1NP (49 ± 18 and 50 ± 20%; P = 0.9).
  
  
  CONCLUSIONS
  Administration of 25OHD(3) is not an indispensable requirement for bisphosphonates to develop their bone antiresorptive effect. In fact, in patients with vitamin D sufficiency, no benefit is observed when the vitamin is added. However, in patients with vitamin D deficiency, an approximately 25% greater fall in the bone resorption marker CTX is seen with its administration.
authors.affiliation: Department of Internal Medicine, Hospital Universitario Marqués de Valdecilla-Instituto de Formación e Investigación Marqués de Valdecilla (IFIMAV), Universidad de Cantabria, Red Temática de Investigación Cooperativa en Envejecimiento y Fragilidad (RETICEF), E-39008 Santander, Spain
authors.forename: José M
authors.initials: JM
authors.lastname: Olmos
authors.forename: José L
authors.initials: JL
authors.lastname: Hernández
authors.forename: Javier
authors.initials: J
authors.lastname: Llorca
authors.forename: Daniel
authors.initials: D
authors.lastname: Nan
authors.forename: Carmen
authors.initials: C
authors.lastname: Valero
authors.forename: Jesús
authors.initials: J
authors.lastname: González-Macías
mesh_terms: D000368:Aged; D019386:Alendronate / Q000008:administration & dosage / Q000627:therapeutic use*; D015415:Biomarkers / Q000032:analysis / Q000097:blood*; D015519:Bone Density / Q000187:drug effects; D050071:Bone Density Conservation Agents / Q000008:administration & dosage / Q000627:therapeutic use; D016723:Bone Remodeling / Q000187:drug effects*; D002112:Calcifediol / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D004338:Drug Combinations; D004347:Drug Interactions; D005260:Female; D006801:Humans; D008875:Middle Aged; D015663:Osteoporosis, Postmenopausal / Q000097:blood / Q000188:drug therapy*; D010281:Parathyroid Hormone / Q000097:blood*; D016896:Treatment Outcome
chemical_list: D015415:Biomarkers; D050071:Bone Density Conservation Agents; D004338:Drug Combinations; D010281:Parathyroid Hormone; D002112:Calcifediol; D019386:Alendronate