Hip bone loss is attenuated with 1000 IU but not 400 IU daily vitamin D3: A 1-year double-blind RCT in postmenopausal women

Abstract

Few year-long vitamin D supplementation trials exist that match seasonal changes. The aim of this study was to determine whether daily oral vitamin D 3 at 400 IU or 1000 IU compared with placebo affects annual bone mineral density (BMD) change in postmenopausal women in a 1-year double-blind placebo controlled trial in Scotland. White women aged 60 to 70 years (n ¼ 305) were randomized to one of two doses of vitamin D or placebo. Mean BMD loss at the hip was significantly less for the 1000 IU vitamin D group (0.05% AE 1.46%) compared with the 400 IU vitamin D or placebo groups (0.57% AE 1.33% and 0.60% AE 1.67%, respectively) (p < 0.05). Mean (AE SD) baseline 25(OH)D was 33.8 AE 14.6 nmol/L; comparative 25(OH) D change for the placebo, 400 IU, and 1000 IU vitamin D groups was À4.1 AE 11.5 nmol/L, þ31.6 AE 19.8 nmol/L, and þ42.6 AE 18.9 nmol/L, respectively. Treatment did not change markers of bone metabolism, except for a small reduction in PTH and an increase in serum calcium (latter with 1000 IU dose only). The discordance between the incremental increase in 25(OH)D between the 400 IU and 1000 IU vitamin D and effect on BMD suggests that 25(OH)D may not accurately reflect clinical outcome, nor how much vitamin D is being stored.

Effects of Vitamin D Supplementation on Bone Turnover Markers: A Randomized Controlled Trial

“…In line with the lacking effect of vitamin D supplementation on BTMs in the present cohort are the divergent data on the effects of vitamin D supplementation on BMD [21,22,23,24,25,26,27] and fracture risk. In the study by Sanders annual oral administration of high-dose cholecalciferol among older community-dwelling women even resulted in an increased risk of falls and fractures [28].…”

Effect of monthly high‐dose vitamin D on bone density in community‐dwelling older adults substudy of a randomized controlled trial

“…Thus, there was a small BMD benefit in the proximal femur, but not elsewhere, and it was concluded that this was not of a magnitude likely to result in fracture prevention. Of the studies published since that review, Macdonald showed a §% difference in total hip BMD in Scottish postmenopausal women randomized to vitamin D 1000 IU day −1 , compared with vitamin D 400 IU day −1 or placebo over one year . There was no significant effect in the spine.…”

“…The suggestion from the present study that beneficial effects of vitamin D supplementation on bone density occur when the baseline 25‐hydroxyvitamin D level is ≤30 nmol L −1 accords with findings from a number of other recent studies. In the last 20 years (during which time 25‐hydroxyvitamin D assays have been better standardized than previously), those studies which have found positive effects on BMD at least one site have had starting 25‐hydroxyvitamin D levels of 29–36 nmol L −1 . A similar threshold is suggested for vitamin D effects on other putative vitamin D targets, such as reduction in exacerbations of chronic obstructive pulmonary disease , reduction in mortality in the critically ill , and changes in bone and fat mass in the foetus .…”

Vitamin D: Link between Osteoporosis, Obesity, and Diabetes?

“…Some studies showed less than 60% compatibility in the intake of supplements, vitamin D, and calcium [49,50] and that the follow-up treatment is essential to verify the success of any intervention. Furthermore, the 400 IU/day dose of vitamin D is insufficient to raise and maintain serum levels within the normal range and to decrease the risk of hip and other nonvertebral fractures [44,57]. Bischoff-Ferrari et al .…”