All corrections
Wikipedia March 19, 2026 at 05:49 PM

en.wikipedia.org/wiki/Vitamin_D_deficiency

2 corrections found

1
Claim
Most vitamin D is converted to 25(OH)D in the serum
Correction

This is anatomically wrong: vitamin D is first converted to 25-hydroxyvitamin D in the liver, not in the serum.

Full reasoning

Authoritative medical references describe the first activation step of vitamin D as hepatic (in the liver), not something that happens "in the serum." MedlinePlus states: "Before your body can use vitamin D, your liver must change it into another form called 25 hydroxyvitamin D, or 25(OH)D." The NIH Office of Dietary Supplements likewise says: "The first hydroxylation, which occurs in the liver, converts vitamin D to 25-hydroxyvitamin D [25(OH)D]."

So the test target is correctly named, but the article's location of the conversion step is incorrect. Serum 25(OH)D is measured in blood, but it is primarily produced by liver hydroxylation.

2 sources
2
Claim
determined that 32% of Americans were deficient during that period (8% at risk of deficiency, and 24% at risk of inadequacy).
Correction

This misstates the CDC report. CDC did not say 32% were deficient; it reported about 8% at risk of deficiency and about one-quarter at risk of inadequacy.

Full reasoning

The article collapses two different CDC categories into one. In the CDC/NCHS Data Brief on U.S. vitamin D status, NHANES 2001-2006 data are divided into:

  • 8% at risk of vitamin D deficiency (serum 25OHD less than 30 nmol/L), and
  • about one-quarter at risk of inadequacy (30-49 nmol/L).

The CDC report does not say that 32% were "deficient." It says roughly two-thirds were sufficient, about one-quarter were at risk of inadequacy, and 8% were at risk of deficiency. So the Wikipedia text incorrectly relabels inadequacy as deficiency.

2 sources
  • Vitamin D Status: United States, 2001-2006

    About one-quarter were at risk of vitamin D inadequacy (serum 25OHD 30-49 nmol/L), and 8% were at risk of vitamin D deficiency (serum 25OHD less than 30 nmol/L).

  • Vitamin D Status: United States, 2001-2006

    In 2001-2006, two-thirds (67%) of persons aged 1 year and over had serum 25OHD values considered sufficient. Roughly one quarter of the population had serum 25OHD values that put them at risk of inadequacy. Eight percent were at risk of deficiency.

Model: OPENAI_GPT_5 Prompt: v1.16.0