Changes in vitamin D metabolites during teriparatide treatment.

Bone. 2012 Jun;50(6):1368-71. Epub 2012 Mar 9.
Cosman F, Dawson-Hughes B, Wan X, Krege JH.
Clinical Research Center, Helen Hayes Hospital, West Haverstraw, NY 10993, USA. cosmanf at helenhayeshosp.org

Parathyroid hormone (PTH) increases the conversion of 25-hydroxyvitamin D [25(OH)D] to 1,25 dihydroxyvitamin D [1,25(OH)(2)D]. The purpose of this study was to assess the changes in serum concentration of vitamin D metabolites 1,25 dihydroxyvitamin D [1,25(OH)(2)D] and 25-hydroxyvitamin D [25(OH)D] during teriparatide 20 ?g/day (teriparatide) therapy in the double-blind Fracture Prevention Trial of postmenopausal women with osteoporosis and in the male study of men with osteoporosis.

Patients were randomized to teriparatide or placebo and received daily supplements of calcium 1000 mg and vitamin D 400-1200 IU. Serum concentrations of 1,25(OH)(2)D and 25(OH)D were measured.

In women (N=336), median 1,25(OH)(2)D concentrations at 1 month increased from baseline by 27% (P<0.0001) in the teriparatide group versus -3% (P=0.87) in the placebo group (between group P<0.0001). At 12 months, the increase was 19% (P<0.0001) in the teriparatide group versus -2% (P=0.23) in the placebo group (P<0.0001). Median 25(OH)D concentrations at 12 months decreased by 19% (P<0.0001) in the teriparatide group versus 0% (P=0.13) in the placebo group (P<0.0001).

In men (N=287), median 1,25(OH)(2)D concentrations at 1 month increased by 22% (P<0.0001) in the teriparatide group versus 0% (P=0.99) in the placebo group (P<0.0001). At 12 months, the increase was 14% (P<0.0001) in the teriparatide group versus 5% (P=0.004) in the placebo group (P=0.17). Median 25(OH)D concentrations at 12 months decreased by 11% (P=0.001) in the teriparatide group versus an increase of 1% (P=0.20) in the placebo group (P=0.003).

Therefore, treatment with teriparatide increases 1,25(OH)(2)D concentrations and decreases 25(OH)D concentrations.

Copyright © 2012 Elsevier Inc. All rights reserved.

PMID: 22426307
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Observations by Vitamin D Life

1. Teriparatide (Forteo) apparently works by increasing active level of vitamin D in the body
2. The vitamin D 400-1200 IU is fairly small
   wonder what would have happened if both sides of the RCT had been taking a useful amount - say 4,000 IU
3. Seems like a person with osteoporosis can get the benefits of teriparatide treatment by just taking more vitamin D
   without the cost or side-effects

See also Vitamin D Life

• Overview Osteoporosis and vitamin D
• Overview Fractures and vitamin D

See also web

• Factors Associated with Persistence with Teriparatide Therapy: Results from the DANCE Observational Study 2011
  ‘’ Only 16% to 50% of patients persist with therapy 12 months after initiation’’
• Vitamin D supplementation is crucial for patients taking Forteo April 2012 - behind a $5 paywall
  Discussion of this paper