French protocol effective in raising 25OHD levels in normal-weight adults
MedWire News: Standardized vitamin D supplementation with 100,000 IU vials is effective in raising serum 25-hydroxy vitamin D (25OHD) levels in normal-weight patients, research shows.
The treatment protocol was ineffective for increasing 25OHD levels in overweight patients, however.
"It could be explained by the fact that vitamin D is a liposoluble vitamin, so it is partially stored in adipocytes," write Pascale Guillot (CHU Hôtel-Dieu, Nantes, France) and colleagues in the journal Joint Bone Spine.
Overweight patients may also be less likely to get outside for sunlight or lack sufficient calcium in their diets, suggest the researchers.
The supplementation protocol tested in the study is the one most frequently used in France for correcting vitamin D insufficiency or deficiency in patients with osteoporosis or osteopenia.
Vitamin D insufficiency/deficiency was defined as a serum 25OHD concentration of less than 30 ng/mL.
In France, four vials of 100,000 IU vitamin D3 are prescribed to patients when serum 25OHD levels are less than 10 ng/dL, three vials when 25OHD concentrations range between 10 and 20 ng/mL, and two vials when 25OHD concentrations range between 20 and 30 ng/mL.
The 254 patients included in the study were given vials every 2 weeks.
At 1 month of follow-up, 198 (77%) of the patients had a serum 25OHD level more than 30 ng/dL, irrespective of their vitamin D status at baseline.
Among those with a body mass index (BMI) less than 25 kg/m2, 85% achieved serum 25OHD concentrations over 30 ng/mL compared with just 66% of overweight individuals with a BMI over 25 kg/m2.
"This suggests that higher dosages should be administered in vitamin D insufficient overweight patients with osteoporosis/osteopenia," state Guillot and colleagues.
At the 2- and 3-month follow-ups, 25OHD concentrations significantly declined, with just 55% and 46% of patients having a serum concentration greater than 30 ng/mL, respectively.
These data "suggest that regular doses should be started quite soon after completion of the loading dose that we tested," say researchers.
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