Calcium supplementation reduces risk of bone fracture and bone loss in older people

Dr Benjamin Tang, University of Western Sydney, Sydney, Australia, and colleagues based their findings on a meta-analysis (a pooled analysis of previous trials) of 17 studies featuring 52625 people all aged over 50 years, with an average treatment time of 3.5 years. They found that where the compliance rate was high (i.e. patients were sticking to the dosing regimen correctly), there was a 24% fracture risk reduction.

The risk reductions were better with calcium doses of over 1200mg compared with doses of less than 1200mg (20% versus 6% reduction), and with vitamin D doses of 800 IU (international units) or more than with does less than 800IU (16% reduction versus 13% reduction). The treatment effect was also greater in individuals who were elderly, lived in institutions, had a low bodyweight, had a low calcium intake, or were at a higher baseline risk than other individuals. The authors believe those in institutions may have benefited more due to assistance complying with the dosing regimen, eg. by nurses making sure patients took their supplements when required.

In a separate part to the study, the researchers did a meta-analysis of 23 trials that reported bone density as an outcome, and found that calcium supplementation alone, or in combination with vitamin D supplementation also reduced the rate of bone loss at the hip by 0.54% and at the spine by 1.19%.

The authors conclude: “Our meta-analysis has shown that calcium supplementation, alone or in combination with vitamin D, is effective in the preventive treatment of osteoporotic fracture… poor compliance is a major obstacle to obtaining the full benefit of calcium supplementation.”

They add: “Although addition of vitamin D supplementation was not shown to offer additional risk reduction over and above the use of calcium alone, a significant difference was observed between the effects of different vitamin D doses.”

In an accompanying Comment, Dr Jean-Yves Reginster, Bone and Cartilage Metabolism Unit, Liege, Belgium, says: “Unlike previous meta-analyses, Tang provides clear answers to several questions which could be of immediate practical importance for the daily management of osteoporosis….Tang and colleagues contribution is important because it paves the way for future research aiming at the best clinical, pharmacological, and economic optimisation of the use of calcium and vitamin D in patients at increased risk of osteoporotic fractures.”