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 .
Human serum 25-hydroxycholecalciferol response to extended oral dosing with cholecalciferol.
BACKGROUND The cholecalciferol inputs required to achieve or maintain any given serum 25-hydroxycholecalciferol concentration are not known , particularly within ranges comparable to the probable physiologic supply of the vitamin . OBJECTIVES The objectives were to establish the quantitative relation between steady state cholecalciferol input and the result ing serum 25-hydroxycholecalciferol concentration and to estimate the proportion of the daily requirement during winter that is met by cholecalciferol reserves in body tissue stores . DESIGN Cholecalciferol was administered daily in controlled oral doses labeled at 0 , 25 , 125 , and 250 micro g cholecalciferol for approximately 20 wk during the winter to 67 men living in Omaha ( 41.2 degrees N latitude ) . The time course of serum 25-hydroxycholecalciferol concentration was measured at intervals over the course of treatment . RESULTS From a mean baseline value of 70.3 nmol/L , equilibrium concentrations of serum 25-hydroxycholecalciferol changed during the winter months in direct proportion to the dose , with a slope of approximately 0.70 nmol/L for each additional 1 micro g cholecalciferol input . The calculated oral input required to sustain the serum 25-hydroxycholecalciferol concentration present before the study ( ie , in the autumn ) was 12.5 micro g ( 500 IU)/d , whereas the total amount from all sources ( supplement , food , tissue stores ) needed to sustain the starting 25-hydroxycholecalciferol concentration was estimated at approximately 96 micro g ( approximately 3800 IU)/d . By difference , the tissue stores provided approximately 78 - 82 micro g/d . CONCLUSIONS Healthy men seem to use 3000 - 5000 IU cholecalciferol/d , apparently meeting > 80 % of their winter cholecalciferol need with cutaneously synthesized accumulations from solar sources during the preceding summer months . Current recommended vitamin D inputs are inadequate to maintain serum 25-hydroxycholecalciferol concentration in the absence of substantial cutaneous production of vitamin
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 .