|Table 1: Proportion (%) of participants with serum 25(OH)D<25, 25−50, 50−75, or >75 nmol/l at baseline, 3, 6, and 12 months according to treatment group 800 IU/day, 100,000 IU/3 months or sunshine exposure (Wicherts. 2010. Table 2)|
mean serum 25(OH)D increased to 53 nmol/l with 800 IU/day, to 50.5 nmol/l with 100,000 IU/3 months, and to 29.1 nmol/l with advised sunlight exposure.Though, even according to the "old" reference ranges, a 25(OH)D level <30 nmol/l does not ascertains a sufficient supply with a vitamin the importance of which scientists come to realize only in the last couple of years. Wicherts would thus not only have to conclude that
[...] Vitamin D supplementation is more effective than advised sunlight exposure for treating vitamin D deficiency in non-western immigrants,but also, that vitamin D supplementation is indicated in non-western (dark skinned) immigrants to the northern hemisphere, where sun exposure is limited and insufficient to provide them with sufficient amounts of vitamin D.