title: Reduction of Parathyroid Hormone with Vitamin D Supplementation in Blacks: A Randomized Controlled Trial.
abstract: BACKGROUND
  Response of parathyroid hormone (PTH) to vitamin D supplementation is determined by the baseline PTH level and change in vitamin D status. Conflicting reports in Blacks exist on the PTH response to vitamin D to supplementation.
  
  
  METHODS
  During 3 winters from 2007-2010, 328 healthy Blacks (median age, 51 years) living in Boston, MA were randomized into a 4-arm, double-blind trial for 3 months of placebo, 1000, 2000, or 4000 IU of vitamin D3. PTH was measured in 254 participants at baseline and at the end of vitamin D supplementation period.
  
  
  RESULTS
  The differences in PTH between baseline and 3 months were 3.93 pg/mL for those receiving placebo, -3.37 pg/mL for those receiving 1000 IU/d, -6.76 pg/mL for those receiving 2000 IU/d, and -8.99 pg/mL for those receiving 4000 IU/d ( -2.98 pg/mL for each additional 1000 IU/d of vitamin D3; p<0.001).
  
  
  CONCLUSIONS
  We found a significant decrease in PTH with increasing doses of vitamin D supplementation up to intakes of 4000 IU/d in Blacks. Clinical Trials.gov: NCT00585637.
authors: Division of Preventive Medicine, Brigham and Women's Hospital, Boston, MA; Harvard Medical School, Boston, MA.
authors: Paulette D
authors: PD
authors: Chandler
authors: Division of Policy Translation and Leadership Development, Harvard School of Public Health, Boston, MA.
authors: Foluso
authors: F
authors: Agboola
authors: Harvard Medical School, Boston, MA; Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA.
authors: Kimmie
authors: K
authors: Ng
authors: Department of Epidemiology and Biostatistics, College of Human Medicine, Michigan State University, East Lansing, MI.
authors: Jamil B
authors: JB
authors: Scott
authors: Department of Surgery, Division of Public Health Sciences, Washington University School of Medicine, St. Louis, MO.
authors: Bettina F
authors: BF
authors: Drake
authors: Department of Psychology and Neuroscience, Duke University, Durham, NC.
authors: Gary G
authors: GG
authors: Bennett
authors: Harvard Medical School, Boston, MA; Division of Gastroenterology, Massachusetts General Hospital, Boston, MA.
authors: Andrew T
authors: AT
authors: Chan
authors: Division of Pediatrics, Medical University of South Carolina, Charleston, SC.
authors: Bruce W
authors: BW
authors: Hollis
authors: Harvard Medical School, Boston, MA; Center for Community-Based Research, Dana-Farber Cancer Institute, Boston, MA.
authors: Karen M
authors: KM
authors: Emmons
authors: Harvard Medical School, Boston, MA; Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, MA.
authors: Charles S
authors: CS
authors: Fuchs
authors: Harvard Medical School, Boston, MA; Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, BostoN; Departments of Nutrition and Epidemiology, Harvard School of Public Health, Boston, MA.
authors: Edward L
authors: EL
authors: Giovannucci
keywords: Blacks; parathyroid hormone; supplementation; vitamin D