Vitamin D Deficiency

To the Editor: Holick's review of vitamin D deficiency (July 19 issue) 1 is timely. We agree 2 that the serum concentration of 25-hydroxyvitamin D should exceed 20 ng per milliliter to avoid bone problems. Data supporting much higher levels for bone or general health are weak and do not fulfill the criteria of evidence-based medicine. 3 – 5 Requiring levels above 32 ng per milliliter implies that more than 80% of the European population and half of the world population are vitamin D–deficient. In Table 3 of his review, Holick recommends about 800 IU of vitamin D per day but also states that . . .