title: Three-year follow-up of serum 25-hydroxyvitamin D, parathyroid hormone, and bone mineral density in nursing home residents who had received 12 months of daily bread fortification with 125 μg of vitamin D₃.
abstract: BACKGROUND
  We conducted a single-arm clinical trial in institutionalized seniors, on the effects of high-dose vitamin D3-fortified bread daily intake (clinicaltrials.gov registration NCT00789503).
  
  
  METHODS
  At 1 and 3 years after the dietary fortification was stopped, serum 25-hydroxyvitamin D (25(OH)D), parathyroid hormone (PTH) and bone mineral density were measured in 23 of the original study subjects, aged 60-82 years who had consumed bread buns (100 g) fortified with 320 mg elemental calcium and 125 μg (5,000 IU) vitamin D3 daily for one year.
  
  
  RESULTS
  At the end of the 1-year supplementation phase (receiving vitamin D3 fortified bread daily), mean (SD) serum 25(OH)D was 127.3 ± 37.8 nmol/L (baseline for this follow-up). At 1-year follow-up, the serum 25(OH)D was 64.9 ± 24.8 nmol/L (p = 0.001, vs. baseline); and at 3-year follow-up it was 28.0 ± 15.0 nmol/L (p = 0.001 vs. baseline). Serum PTH was 18.8 ± 15.6 pg/ml at baseline while at Year 3 it was 48.4 ± 18.4 pg/ml (p = 0.001 vs. baseline). Lumbar spine BMD did not change from baseline to Year 3. However, by Year 3, hip BMD had decreased (0.927 ± 0.130 g/cm² vs. 0.907 ± 0.121 g/cm², p = 0.024).
  
  
  CONCLUSIONS
  Vitamin D nutritional status exhibits a long half-life in the body, and a true steady-state plateau may not even be reached 1 year after a discontinuation in dose. Furthermore, once the need for vitamin D has been established, based on a low baseline serum 25(OH)D concentrations, the appropriate action is to maintain corrective vitamin D supplementation over the long term.
authors.affiliation: Department of Pathophysiology, Grigore T, Popa University of Medicine and Pharmacy, 16 Universitatii str, Iasi 700115, Romania. vmocanu@iasi.mednet.ro.
authors.forename: Veronica
authors.initials: V
authors.lastname: Mocanu
authors.forename: Reinhold
authors.initials: R
authors.lastname: Vieth
mesh_terms: D015502:Absorptiometry, Photon; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D015519:Bone Density; D001939:Bread; D002112:Calcifediol / Q000097:blood*; D002136:Calcium, Dietary / Q000627:therapeutic use; D002762:Cholecalciferol / Q000627:therapeutic use*; D005500:Follow-Up Studies; D005527:Food, Fortified; D006621:Hip Joint / Q000000981:diagnostic imaging; D006707:Homes for the Aged; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging; D008875:Middle Aged; D009735:Nursing Homes; D010024:Osteoporosis / Q000000981:diagnostic imaging / Q000209:etiology / Q000517:prevention & control*; D010281:Parathyroid Hormone / Q000097:blood; D012008:Recurrence; D012383:Romania; D014808:Vitamin D Deficiency / Q000097:blood / Q000178:diet therapy* / Q000503:physiopathology
chemical_list: D002136:Calcium, Dietary; C470125:PTH protein, human; D010281:Parathyroid Hormone; D002762:Cholecalciferol; D002112:Calcifediol