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 malabsorption in the elderly: the effect of treatment with oral 25‐hydroxyvitamin D3
Abstract . Calcium malabsorption is common in the elderly and may contribute to the development of age‐related bone loss . To investigate its cause , we have measured  radio‐calcium absorption , plasma 25‐hydroxyvitamin D , 1,25‐dihydroxyvitamin D and parathyroid hormone  in forty‐eight elderly women with a normal plasma creatinine . Calcium malabsorption was associated with low 25‐hydroxyvitamin D concentrations and was corrected by increasing these into the normal range by treatment with oral 25‐hydroxyvitamin D3 . Treatment also increased 1,25‐dihydroxyvitamin D , and decreased parathyroid hormone concentrations
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 .