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 cholecalciferol plus calcium on falling in ambulatory older men and women: a 3-year randomized controlled trial.
BACKGROUND A recent meta- analysis found that cholecalciferol ( vitamin D ) should reduce falls by more than 20 % . However , little is known about whether supplemental cholecalciferol plus calcium citrate malate will lower the long-term risk of falling in men , active older individuals , and older individuals with higher 25-hydroxyvitamin D levels . METHODS We studied the effect of 3-year supplementation with cholecalciferol-calcium on the risk of falling  at least once in 199 men and 246 women 65 years or older and living at home . Individuals received 700 IU of cholecalciferol plus 500 mg of calcium citrate malate per day or placebo in a r and omized double-blind manner . Subjects were classified as less physically active if physical activity was below the median level . Low 25-hydroxyvitamin D levels were classified as those below 32 ng/mL ( < 80 nmol/L ) . RESULTS In 3 years , 55 % of women and 45 % of men reported at least 1 fall . Mean + /- SD baseline 25-hydroxyvitamin D levels were 26.6 + /- 12.7 ng/mL ( 66.4 + /- 31.7 nmol/L ) in women and 33.2 + /- 14.2 ng/mL ( 82.9 + /- 34.9 ) in men . Cholecalciferol-calcium significantly reduced the odds of falling in women ( odds ratio [ OR ] , 0.54 ; 95 % confidence interval [ CI ] , 0.30 - 0.97 ) , but not in men ( OR , 0.93 ; 95 % CI , 0.50 - 1.72 ) . Fall reduction was most pronounced in less active women ( OR , 0.35 ; 95 % CI , 0.15 - 0.81 ) . Baseline 25-hydroxyvitamin D level did not modulate the treatment effect . CONCLUSIONS Long-term dietary cholecalciferol-calcium supplementation reduces the odds of falling in ambulatory older women by 46 % , and especially in less active women by 65 % . Supplementation had a neutral effect in men independent of their physical activity level
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 .