Serum 25-hydroxyvitamin D concentration

Method

Serum or plasma 25-hydroxyvitamin D concentration by competitive immunoassay or by LC-MS/MS, as the achieved concentration on supplementation. The assay is recorded on the edge, since immunoassays and LC-MS/MS disagree systematically and handle the D2 form differently.

The method is part of the endpoint identity. Studies measuring the same quantity by a different method are held as separate endpoints.

Notes

"25OHD" declared 2026-08-27 alongside a tokenizer fix, and NEITHER works without the other. Papers write this endpoint "25(OH)D", and `contentWords` used to turn every non-alphanumeric into a space, giving 25 / oh / d — all filtered as too short, leaving the span an EMPTY SET that could match nothing. Declaring an abbreviation could not have helped, because the declaration was annihilated the same way. So parentheses with a non-space on both sides are now removed rather than split on, which turns "25(OH)D" into the single token this abbreviation supplies. A parenthetical aside still splits normally. Serum 1,25-dihydroxyvitamin D is the near-miss and is routinely printed beside it. This node is the storage form that indexes vitamin D status; 1,25(OH)2D is the tightly PTH-regulated active hormone and can be normal or frankly HIGH in deficiency, so the two can move in opposite directions in the same patient and a merged 'vitamin D' node would report deficiency as sufficiency. Unit trap: ng/mL times 2.496 gives nmol/L, and both are common in this literature. Distinct also from dietary or supplemental vitamin D intake, which is an exposure rather than an outcome.

Findings

1 finding from 1 compound, strongest first.

• calciol — increases

  BLikelyGrade B, Likely. Human evidence, limited replication or design limits.Finding

  “25(OH)D was similar at baseline in the two groups, but higher in women randomized to cholecalciferol [68.2 nmol/l (standard deviation {SD} 21.9 nmol/l)] than placebo [43.4 nmol/l (SD 22.4 nmol/l)] at 34 weeks’ gestation (P < 0.001).”

  Study

  RCT

  Dose

  cholecalciferol 1000 IU/day orally, commenced before 17 weeks' gestation and continued until delivery

  Population

  Pregnant women over 18 years with a singleton pregnancy and screening 25(OH)D between 25 and 100 nmol/L, recruited at 11-14 weeks' gestation at three UK hospitals; 27.5% of the placebo group and 29.1% of the cholecalciferol group also used additional vitamin D supplements of up to 400 IU/day, and all received standard antenatal care.

  Does antenatal cholecalciferol supplementation affect the mode or timing of delivery? Post hoc analyses of the MAVIDOS randomized controlled trial.2023PMID:36585903Industry funded