How could bone density be significantly higher in the active CaD group than in the placebo group when there was no difference in the rate of hip fractures?
There are several possible explanations why participants in the active CaD group had higher bone density, but no significant difference in hip fractures. It may be that the effect of CaD supplements on bone mineral density is not enough to show a large effect on actual hip fractures. It may also be that the bone quality, which is not measured by bone mineral density, was not better in the active group. Also, many CaD Study participants were already at a low risk for hip fractures when they joined the study and that might make finding differences less likely. Many participants had high personal calcium intake, they had higher than average weights, and many were taking postmenopausal hormone therapy. All of these factors decrease a womans risk for hip fractures. Finally, the dose of vitamin D (400 IU) may have been too low to affect hip fracture risk. More studies are needed to determine if higher amounts of vitamin D supplements will help to prevent hip fracture.
