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How well are the optimal serum 25OHD concentrations reached in high‐dose intermittent vitamin D therapy? a placebo‐controlled study on comparison between 100 000 IU and 200 000 IU of oral D 3 every 3 months in elderly women
Author(s) -
Välimäki VilleValtteri,
Löyttyniemi Eliisa,
Pekkarinen Tuula,
Välimäki Matti J.
Publication year - 2016
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/cen.13014
Subject(s) - placebo , endocrinology , medicine , vitamin d and neurology , pathology , alternative medicine
Summary Objective Intermittent dosing may improve adherence to vitamin D therapy. Dosing regimen should maintain optimal serum 25‐hydroxyvitamin D (25 OHD ) levels over all the year. We compared two dosing regimens, the primary outcome being the percentage of 25 OHD measurements reaching the targets of 75 nmol/l or 50 nmol/l after baseline. Design Randomized, placebo‐controlled parallel group comparison. Patients Sixty women aged 75·0 ± 2·9 years. Interventions 100 000 IU (group 1D) or 200 000 IU (2D) of vitamin D 3 or placebo orally every 3 months plus calcium 1 g daily for 1 year. Measurements Serum 25 OHD , 1,25‐dihydroxyvitamin D, PTH , sclerostin, ionized calcium, urinary calcium, renal function, bone turnover markers. Results Serum 25 OHD increased, but the difference between two doses was of borderline significance ( P = 0·0554; area under curve analysis). Immediate postadministrative increases were higher in the 2D vs 1D group ( P < 0·05) after 3 and 6 months’ dosing. In the 1D and 2D groups, 51·2% and 57·7% of all on‐treatment measurements reached the target of 75 nmol/l. PTH levels differed marginally ( P = 0·0759) due to tendency to lowering immediately after vitamin D boluses. Urinary calcium differed between the groups ( P = 0·0193) due to increases 1 week after vitamin D dosing. Conclusions The doses of 100 000 or 200 000 IU of oral cholecalciferol every 3 months were not capable of stabilizing 25 OHD levels over the target of 75 nmol/l over the year. To improve the efficacy of high‐dose vitamin D therapy, the interval between boluses has to be shortened instead of increasing their size.