There was a suggestion that whole-body or lumbar spine BMD may be a useful biomarker in older people but not in adolescents .
This systematic review confirmed that circulating 25(OH)D is a robust and reliable marker of vitamin D status .
BACKGROUND Although serum 25-hydroxyvitamin D [ 25(OH)D ] is the currently accepted vitamin D status marker of choice , use of other biomarkers or functional endpoints have been suggested .
OBJECTIVE The objective was to systematic ally review the effectiveness of 25(OH)D , parathyroid hormone ( PTH ) , bone turnover markers , bone mineral density ( BMD ) , and calcium absorption as biomarkers of vitamin D status .
Calcium and cholecalciferol: effects of small supplements in normal men.
The effect of small calcium and vitamin D supplements on mineral metabolism in normal persons is unclear . To investigate the biochemical response to these medications , we administered 1000 mg Ca and 25 micrograms cholecalciferol per day or a placebo to 92 normal men for 1 y. The Ca and cholecalciferol were tolerated well . 25-Hydroxycholecalciferol [ 25-(OH)D ] and 24,25-dihydroxycholecalciferol [ 24,25-(OH)2D ] levels rose in treated subjects ; there was no definite change in 1,25-(OH)2D concentrations . The average difference in 25-(OH)D levels between treated and untreated subjects was 30 nmol/L at 1 y. Fasting serum Ca , alkaline phosphatase , creatinine , and parathyroid hormone levels and the fasting urinary excretion of Ca , phosphorus and cAMP , were not affected . However , 24-h urinary Ca excretion was higher in the supplemented group ( 3.5 + /- 1.9 vs 4.7 + /- 1.7 mmol/d , p = 0.006 ) . Serum P concentrations were slightly higher in the supplemented group at 1 y. In normal men  small calcium and cholecalciferol supplements are safe , provide adequate vitamin D nutrition and apparently increase net gastrointestinal Ca absorption
There was a suggestion that whole-body or lumbar spine BMD may be a useful biomarker in older people but not in adolescents .
This systematic review confirmed that circulating 25(OH)D is a robust and reliable marker of vitamin D status .
BACKGROUND Although serum 25-hydroxyvitamin D [ 25(OH)D ] is the currently accepted vitamin D status marker of choice , use of other biomarkers or functional endpoints have been suggested .
OBJECTIVE The objective was to systematic ally review the effectiveness of 25(OH)D , parathyroid hormone ( PTH ) , bone turnover markers , bone mineral density ( BMD ) , and calcium absorption as biomarkers of vitamin D status .