Manish P Ponda1, David McGee, Jan L Breslow. 1. Laboratory of Biochemical Genetics and Metabolism, The Rockefeller University, New York, New York 10065.
Abstract
CONTEXT: Vitamin D deficiency, defined by the total serum 25-hydroxyvitamin D [25(OH)D] level, is common and more prevalent among Blacks than whites. Vitamin D-binding protein (DBP) levels vary with race and may modulate "bioavailable" levels of 25(OH)D. OBJECTIVE: To determine the effect of DBP levels on the functional response to vitamin D. SETTING AND DESIGN: A randomized, placebo-controlled trial of vitamin D repletion for 2 mo, which took place at an outpatient research unit. Participants included 150 vitamin D-deficient (25(OH)D <20 ng/mL) adults. Participants were randomly assigned to receive either 50,000 IU of vitamin D3 or placebo weekly for 8 weeks. This is a post-hoc analysis using DBP, 25(OH)D, PTH, and calcium levels. RESULTS: Blacks had lower total 25(OH)D (12 vs 15 ng/mL, P < .001) and DBP levels (119 vs 234 μg/mL, P < .001) than non-Blacks. DBP levels were similar before and after vitamin D3 or placebo treatment (r = 0.98, P < .001). Baseline total 25(OH)D levels were a significant determinant of baseline PTH levels (P < .001). The change in total 25(OH)D was associated with the change in PTH (P < 0.001) and calcium levels (P < .05). In contrast, DBP levels were not a determinant of baseline PTH (P = .57) nor significantly related to changes in either PTH (P = .53) or calcium levels (P = .88). CONCLUSIONS:DBP levels are stable in Blacks and non-Blacks, and do not change with correction of vitamin D deficiency. Even for individuals with total 25(OH)D levels < 20 ng/mL, Blacks have significantly lower DBP levels than non-Blacks. However, within this range of total 25(OH)D, DBP levels do not influence the effect of vitamin D repletion on PTH or calcium levels.
RCT Entities:
CONTEXT: Vitamin D deficiency, defined by the total serum 25-hydroxyvitamin D [25(OH)D] level, is common and more prevalent among Blacks than whites. Vitamin D-binding protein (DBP) levels vary with race and may modulate "bioavailable" levels of 25(OH)D. OBJECTIVE: To determine the effect of DBP levels on the functional response to vitamin D. SETTING AND DESIGN: A randomized, placebo-controlled trial of vitamin D repletion for 2 mo, which took place at an outpatient research unit. Participants included 150 vitamin D-deficient (25(OH)D <20 ng/mL) adults. Participants were randomly assigned to receive either 50,000 IU of vitamin D3 or placebo weekly for 8 weeks. This is a post-hoc analysis using DBP, 25(OH)D, PTH, and calcium levels. RESULTS: Blacks had lower total 25(OH)D (12 vs 15 ng/mL, P < .001) and DBP levels (119 vs 234 μg/mL, P < .001) than non-Blacks. DBP levels were similar before and after vitamin D3 or placebo treatment (r = 0.98, P < .001). Baseline total 25(OH)D levels were a significant determinant of baseline PTH levels (P < .001). The change in total 25(OH)D was associated with the change in PTH (P < 0.001) and calcium levels (P < .05). In contrast, DBP levels were not a determinant of baseline PTH (P = .57) nor significantly related to changes in either PTH (P = .53) or calcium levels (P = .88). CONCLUSIONS:DBP levels are stable in Blacks and non-Blacks, and do not change with correction of vitamin D deficiency. Even for individuals with total 25(OH)D levels < 20 ng/mL, Blacks have significantly lower DBP levels than non-Blacks. However, within this range of total 25(OH)D, DBP levels do not influence the effect of vitamin D repletion on PTH or calcium levels.
Authors: F F Safadi; P Thornton; H Magiera; B W Hollis; M Gentile; J G Haddad; S A Liebhaber; N E Cooke Journal: J Clin Invest Date: 1999-01 Impact factor: 14.808
Authors: A Nykjaer; D Dragun; D Walther; H Vorum; C Jacobsen; J Herz; F Melsen; E I Christensen; T E Willnow Journal: Cell Date: 1999-02-19 Impact factor: 41.582
Authors: Camille E Powe; Michele K Evans; Julia Wenger; Alan B Zonderman; Anders H Berg; Michael Nalls; Hector Tamez; Dongsheng Zhang; Ishir Bhan; S Ananth Karumanchi; Neil R Powe; Ravi Thadhani Journal: N Engl J Med Date: 2013-11-21 Impact factor: 91.245
Authors: M Abboud; D A Puglisi; B N Davies; M Rybchyn; N P Whitehead; K E Brock; L Cole; C Gordon-Thomson; D R Fraser; R S Mason Journal: Endocrinology Date: 2013-07-03 Impact factor: 4.736
Authors: Rene F Chun; Bradford E Peercy; Eric S Orwoll; Carrie M Nielson; John S Adams; Martin Hewison Journal: J Steroid Biochem Mol Biol Date: 2013-10-04 Impact factor: 4.292
Authors: P W Lambert; P H Stern; R C Avioli; N C Brackett; R T Turner; A Greene; I Y Fu; N H Bell Journal: J Clin Invest Date: 1982-03 Impact factor: 14.808
Authors: John Aloia; Ruban Dhaliwal; Mageda Mikhail; Albert Shieh; Alexandra Stolberg; Louis Ragolia; Melissa Fazzari; Steven A Abrams Journal: J Clin Endocrinol Metab Date: 2015-08-27 Impact factor: 5.958
Authors: P Peris; X Filella; A Monegal; N Guañabens; L Foj; M Bonet; D Boquet; E Casado; D Cerdá; A Erra; C Gómez-Vaquero; S Martínez; N Montalá; C Pittarch; E Kanterewicz; M Sala; X Suris; J L Carrasco Journal: Osteoporos Int Date: 2017-05-02 Impact factor: 4.507
Authors: Naweed S Alzaman; Bess Dawson-Hughes; Jason Nelson; David D'Alessio; Anastassios G Pittas Journal: Am J Clin Nutr Date: 2016-05-18 Impact factor: 7.045
Authors: Kathleen M Hill Gallant; Connie M Weaver; Dwight A Towler; Sowmyanarayanan V Thuppal; Regan L Bailey Journal: Adv Nutr Date: 2016-05-16 Impact factor: 8.701
Authors: Caleigh M Sawicki; Maria I Van Rompay; Lauren E Au; Catherine M Gordon; Jennifer M Sacheck Journal: J Nutr Date: 2016-03-02 Impact factor: 4.798
Authors: Michelle R Denburg; Andrew N Hoofnagle; Samir Sayed; Jayanta Gupta; Ian H de Boer; Lawrence J Appel; Ramon Durazo-Arvizu; Krista Whitehead; Harold I Feldman; Mary B Leonard Journal: J Bone Miner Res Date: 2016-06 Impact factor: 6.741