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From: trigonometry1972 on 21 Jun 2008 15:31
Clin Endocrinol Metab. 2008 Apr 29. [Epub ahead of print]

SHORT-TERM AND LONG-TERM SAFETY OF WEEKLY HIGH-DOSE
VITAMIN D3 SUPPLEMENTATION IN
SCHOOL CHILDREN.

Maalouf J, Nabulsi M, Vieth R, Kimball S,
El-Rassi R, Mahfoud Z, El-Hajj Fuleihan
G.

Calcium Metabolism and Osteoporosis Program,
Department of Internal Medicine,
Department of Pediatrics, School of Medicine,
American University of Beirut,
Beirut, Lebanon;
Department of Nutritional Sciences,
Department of Laboratory
Medicine, University of Toronto,
Toronto, Canada;
Department of Epidemiology and
Population Health,
School of Health Sciences,
American University of Beirut,
Beirut, Lebanon.

Background:
Hypovitaminosis D is prevalent in youth worldwide,
but the safety of vitamin D at doses exceeding
200 IU/day is unknown in this age group. We assessed
the safety of high doses of vitamin D3
administered to apparently healthy school children.

Methods:
short term safety: 25 subjects randomly received
placebo or vitamin D3 at doses of 14,000 IU/wk for
8 weeks. Long term safety: 340 subjects randomly
received placebo, vitamin D3 as 1400 IU or 14,000
IU/week for one year. Biochemical variables
were monitored at 0, 2, 4, 6, 8 weeks, and 8
weeks off therapy in the short term study and
at 0, 6 and 12 months in the long term study.
Results: In both the short term and long term
studies, mean serum calcium and 1,25-OHD levels
did not change in any group. In the short term
study, mean 25-OHD concentrations increased from
44 (+/- 11) ng/ml to 54 (+/- 19) ng/ml in the
treated groups (P=0.033). In the long term study,
mean 25-OHD levels increased from 15+/-8 to
19+/-7 ng/ml (p<0.0001) in subjects receiving
1400 IU/wk; and from 15+/-7 to 36+/-22ng/ml
in the group receiving 14,000 IU/wk (p<0.0001).
No subject developed vitamin D intoxication.

Conclusion:
Vitamin D3 at doses equivalent to
2,000 IU/day for one year is safe in adolescents
and results in desirable vitamin
D levels.


PMID: 18445674
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