Conclusions and Relevance In this systematic review and meta- analysis , neither intermittent nor daily dosing with st and ard doses of vitamin D alone was associated with reduced risk of fracture , but daily supplementation with both vitamin D and calcium was a more promising strategy
Importance Vitamin D and calcium supplements are recommended for the prevention of fracture , but previous r and omized clinical trials ( RCTs ) have reported conflicting results , with uncertainty about optimal doses and regimens for supplementation and their overall effectiveness .
Objective To assess the risks of fracture associated with differences in concentrations of 25-hydroxyvitamin D ( 25[OH]D ) in observational studies and the risks of fracture associated with supplementation with vitamin D alone or in combination with calcium in RCTs .
Treatment of Vitamin D Insufficiency in Postmenopausal Women: A Randomized Clinical Trial.
IMPORTANCE Experts debate optimal 25-hydroxyvitamin D ( 25[OH]D ) levels for musculoskeletal health . OBJECTIVE To compare the effects of placebo , low-dose cholecalciferol , and high-dose cholecalciferol on 1-year changes in total fractional calcium absorption , bone mineral density , Timed Up and Go and five sit-to-st and tests , and muscle mass in postmenopausal women with vitamin D insufficiency . DESIGN , SETTING , AND PARTICIPANTS This r and omized , double-blind , placebo-controlled clinical trial was conducted at a single center in Madison , Wisconsin , from May 1 , 2010 , through July 31 , 2013 , and the final visit was completed on August 8 , 2014 . A total of 230 postmenopausal women 75 years or younger with baseline 25(OH)D levels of 14 through 27 ng/mL and no osteoporosis were studied . INTERVENTIONS Three arms included daily white and twice monthly yellow placebo ( n=76 ) , daily 800 IU vitamin D3 and twice monthly yellow placebo ( n=75 ) , and daily white placebo and twice monthly 50,000 IU vitamin D3 ( n=79 ) . The high-dose vitamin D regimen achieved and maintained 25(OH)D levels≥30 ng/mL. MAIN OUTCOMES AND MEASURES Outcome measures were 1-year change in total fractional calcium absorption using 2 stable isotopes , bone mineral density and muscle mass using dual energy x-ray absorptiometry , Timed Up and Go and five sit-to-st and tests , functional status ( Health Assessment Question naire ) , and physical activity ( Physical Activity Scale for the Elderly ) , with Benjamini-Hochberg correction of P values to control for the false discovery rate . RESULTS After baseline absorption was controlled for , calcium absorption increased 1 % ( 10 mg/d ) in the high-dose arm but decreased 2 % in the low-dose arm ( P = .005 vs high-dose arm ) and 1.3 % in the placebo arm ( P = .03 vs high-dose arm ) . We found no between-arm changes in spine , mean total-hip , mean femoral neck , or total-body bone mineral density , trabecular bone score , muscle mass , and Timed Up and Go or five sit-to-st and test scores . Likewise , we found no between-arm differences for numbers of falls , number of fallers , physical activity , or functional status . CONCLUSIONS AND RELEVANCE High-dose cholecalciferol therapy increased calcium absorption , but the effect was small and did not translate into beneficial effects on bone mineral density , muscle function , muscle mass , or falls . We found no data to support experts ' recommendations to maintain serum 25(OH)D levels of 30 ng/mL or higher in postmenopausal women . Instead , we found that low- and high-dose cholecalciferol were equivalent to placebo in their effects on bone and muscle outcomes in this cohort of postmenopausal women with 25(OH)D levels less than 30 ng/mL. TRIAL REGISTRATION clinical trials.gov Identifier : NCT00933244
Conclusions and Relevance In this systematic review and meta- analysis , neither intermittent nor daily dosing with st and ard doses of vitamin D alone was associated with reduced risk of fracture , but daily supplementation with both vitamin D and calcium was a more promising strategy
Importance Vitamin D and calcium supplements are recommended for the prevention of fracture , but previous r and omized clinical trials ( RCTs ) have reported conflicting results , with uncertainty about optimal doses and regimens for supplementation and their overall effectiveness .
Objective To assess the risks of fracture associated with differences in concentrations of 25-hydroxyvitamin D ( 25[OH]D ) in observational studies and the risks of fracture associated with supplementation with vitamin D alone or in combination with calcium in RCTs .