A new Finnish study found out that nearly 40% of Finnish men aged 18.3-20.6
years were vitamin D deficient in the winter of 2000, while in the previous
summer only 0.9% of them was deficient. The study also found a positive
correlation between serum vitamin D level (25-OHD) and bone mineral content.
The study concludes that vitamin D deficiency is very common in Finnish young
men in the winter, and it may have detrimental effects on the acquisition of
maximal peak bone mass.

Reference:

Valimaki VV, Alfthan H, Lehmuskallio E, Loyttyniemi E, Sahi T, Stenman UH,
Suominen H, Valimaki MJ.
Vitamin d status as a determinant of peak bone mass in young finnish men.
J Clin Endocrinol Metab. 2004 Jan; 89(1): 76-80.
PMID: 14715830 [PubMed - in process]
<URL:http://jcem.endojournals.org/cgi/content/abstract/89/1/76>
<URL:http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=1
4715830&dopt=Abstract>

Abstract:

   "Severe vitamin D deficiency causes rickets, but scarce
   data are available about the extent to which vitamin D
   status determines the development of the peak bone mass
   in young adults. Our aim was to evaluate the prevalence
   of vitamin D deficiency [serum 25-hydroxyvitamin D (25-
   OHD) less than the lower limit of the reference range of
   20-105 nmol/liter] and the relationship between vitamin
   D status and peak bone mass among young Finnish men. A
   cross-sectional study of determinants of peak bone mass
   with data on lifestyle factors collected retrospectively
   was performed in 220 young men, aged 18.3-20.6 yr. One
   hundred and seventy men were recruits of the Finnish
   Army, and 50 were men of similar age who had postponed
   their military service for reasons not related to
   health. Bone mineral content, bone mineral density, and
   scan area were measured in lumbar spine and upper femur
   by dual energy x-ray absorptiometry. Serum 25-OHD
   concentrations were followed prospectively for 1 yr. In
   July 2000, only 0.9% of the men had vitamin D
   deficiency, but 6 months later, in the winter, the
   respective percentage was 38.9%. After adjusting for
   age, height, weight, exercise, smoking, calcium, and
   alcohol intake, there existed a positive correlation
   between serum 25-OHD and bone mineral content at lumbar
   spine (P = 0.057), femoral neck (P = 0.041), trochanter
   (P = 0.010), and total hip (P = 0.025). The correlation
   coefficients for the bone mineral densities at the four
   measurement sites were 0.035, 0.061, 0.056, and 0.068,
   respectively. No correlation was found to scan area. We
   conclude that vitamin D deficiency is very common in
   Finnish young men in the winter, and it may have
   detrimental effects on the acquisition of maximal peak
   bone mass. As in Finland vitamin D supplementation to
   infants is now stopped at the age of 3 yr, it can be
   asked whether at our latitude it should be continued
   from that age onward, not for the prevention of rickets,
   but as prophylaxis for osteoporosis."

--
Matti Narkia