“Normal vitamin D status despite of abundant sun exposure” would have been my title for a study in the JCEM this month. The authors, however, have choosen a different title: “Low vitamin D status despite abundant sun exposure”.
They tested 93 individuals (skateboarders from the A’ala Park Boardshop in Honolulu, Hawaii), all spending 22 hours/week outside and having serum 25-OH-D3 values in the range of 20–60 ng/ml w/o any major PTH increase. I don’t see any reason to declare them therefore as deficient. The authors even admit in the discussion that this would be “counterintuitive”.
Another study published another unexpected finding – diurnal ! variation of 25-OH-D3. Found mainly in women (morning 49.6 ng/ml, noon 36.5 ng/ml, evening 12.9 ng/ml). True variation or artefact?