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 .
Effect of Supplementation with Vitamin D3 and Calcium on Quantitative Ultrasound of Bone in Elderly Institutionalized Women: A Longitudinal Study

Abstract : Supplementation of elderly institutionalized women with vitamin D and calcium  decreased hip fractures and increased hip bone mineral density . Quantitative ultrasound ( QUS ) measurements can be performed in nursing homes , and easily repeated for follow-up . However , the effect of the correction of vitamin D deficiency on QUS parameters is not known . Therefore , 248 institutionalized women aged 62–98 years were included in a 2-year open controlled study . They were r and omized into a treated group ( n = 124 ) , receiving 440 IU of vitamin D3 combined with 500 mg calcium ( 1250 mg calcium carbonate , Novartis ) twice daily , and a control group ( n = 124 ) . One hundred and three women ( 42 % ) , aged 84.5 ± 7.5 years , completed the study : 50 in the treated group , 53 in the  controls  . QUS of the calcaneus , which measures BUA ( broadb and ultrasound attenuation ) and SOS ( speed of sound ) , and biochemical analysis were performed before and after 1 and 2 years of treatment . Only the results of the women with a complete follow-up were taken into account . Both groups had low initial mean serum 25-hydroxyvitamin D levels ( 11.9 ± 1.2 and 11.7 ± 1.2 mg/l ; normal range 6.4–40.2 mg/l ) and normal mean serum parathyroid hormone ( PTH ) levels ( 43.1 ± 3.2 and 44.6 ± 3.5 ng/l ; normal range 10–70 ng/l , normal mean 31.8 ± 2.3 ng/l ) . The treatment led to a correction of the metabolic disturbances , with an increase in 25-hydroxyvitamin D by 123 % ( p50.01 ) and a decrease in PTH by 18 % ( p50.05 ) and of alkaline phosphatase by 15 % ( p50.01 ) . In the controls there was a worsening of the hypovitaminosis D , with a decrease of 25-hydroxyvitamin D by 51 % ( p50.01 ) and an increase in PTH by 51 % ( p50.01 ) , while the serum calcium level decreased by only 2 % ( p5 0.01 ) . After 2 years of treatment BUA increased significantly by 1.6 % in the treated group ( p50.05 ) , and decreased by 2.3 % in the controls ( p50.01 ) . Therefore , the difference in BUA between the treated subjects and the controls ( 3.9 % ) was significant after 2 years ( p50.01 ) . However , SOS decreased by the same amount in both groups ( approximately 0.5 % ) . In conclusion , BUA , but not SOS , reflected the positive effect on bone of supplementation with calcium and vitamin D3 in a population of elderly institutionalized women
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 .