Don Smith

All of you who thought I was talking about sex should get your mind out of the gutter.

I was referring to vitamin D (but more sex would be OK too).

As you can see, the average world-wide level was 54 nmol/L and since we know that it should be >120 nmol/L (and probably > 150 nmol/L), it should be obvious to everyone (even dumb dermatologists) that 5-10 minutes of sunlight exposure to your face and hands once or twice a week just "ain't" getting the job done.

Tanning salons are the answer!

Osteoporos Int. 2008 May 6 [Epub ahead of print]

Global vitamin D levels in relation to age, gender, skin pigmentation and
latitude: an ecologic meta-regression analysis.

Hagenau T, Vest R, Gissel TN, Poulsen CS, Erlandsen M, Mosekilde L, Vestergaard
P.

Department of Endocrinology and Metabolism C, Aarhus Amtssygehus, Aarhus
University Hospital, Aarhus, Denmark.

We performed a meta-analysis of cross-sectional studies on serum 25(OH)D status
globally. Serum 25(OH)D levels on average were 54 nmol/l, were higher in women
than men, and higher in Caucasians than in non-Caucasians. There was no trend in
serum 25(OH)D level with latitude. Vitamin D deficiency was widespread.

INTRODUCTION: We studied vitamin D status (expressed as serum 25-hydroxy-vitamin
D [25(OH)D]) in native subjects worldwide.

METHODS: Meta-analysis and
meta-regression of studies reporting on 25(OH)D in healthy subjects retrieved
from Pubmed, Embase and Web of Science using the terms "serum",
"25-hydroxy-vitamin D", "cholecalciferol", and "human". A total of 394 studies
were included.

RESULTS: The mean 25(OH)D level was 54 nmol/l (95% CI: 52-57
nmol/l). Women had borderline significantly higher 25(OH)D levels than men, and
Caucasians had higher levels than non-Caucasians. 25(OH)D levels were higher in
subjects aged >15 years than in younger subjects. Unadjusted there was no
significant decrease in 25(OH)D with latitude (slope of curve -0.03 +/- 0.12
nmol/l per degree latitude north or south of equator, p = 0.8). There was a
significant decline with latitude for Caucasians (-0.69 +/- 0.30 nmol/l per
degree, p = 0.02), but not for non-Caucasians (0.03 +/- 0.39 nmol/l per degree, p
= 0.14). After adjustment for age, gender, and ethnicity, no overall correlation
was present between 25(OH)D and latitude (-0.29 +/- 0.24 nmol/l per degree, p =
0.23).

CONCLUSION: There was no overall influence of latitude on 25(OH)D.
However, in separate analyses 25(OH)D decreased with latitude in Caucasians but
not in non-Caucasians. A widespread global vitamin D insufficiency was present
compared with proposed threshold levels.