Osteoporosis: Calcium and vitamin D

Combination Use

•  Evidence supporting the benefit of calcium and vitamin D supplementation in patients with osteoporosis comes largely from prospective, randomized, placebo-controlled trials
• Although a number of trials have reported a beneficial effect of calcium or calcium plus vitamin D on bone density in postmenopausal women and older men the data on fracture rates are more variable
• Some trials have reported a reduction in fracture, but large randomized trials have not shown any reduction in fracture risk with calcium plus vitamin D
•  In the largest of these trials (Women's Health Initiative [WHI]), however, subgroup analysis revealed that calcium and vitamin D supplementation was associated with reduced fracture incidence in those subjects who were most compliant
• In a WHI trial, the risk of hip fracture with calcium-vitamin D (intention-to-treat analysis) was lower than placebo, although this was not statistically significant (hazard ratio [HR] 0.88, 95% CI 0.72-1.08). In all subjects, the risk of kidney stones was increased with calcium-vitamin D supplementation (HR 1.17. 95% CI 1.02-1.34).

Calcium VS Vitamin D

• In many of these trials, it is difficult to differentiate the effect of calcium from that of vitamin D.
• Randomized trials of calcium only or vitamin D only have shown mixed results, likely due to differences in patient populations and study design
• Findings suggest that supplementation with vitamin D does not reduce the risk of fracture unless there is adequate calcium.

Recommendations

• The optimal intake of calcium and vitamin D is uncertain. In postmenopausal women with osteoporosis, 1200 mg of calcium daily (total diet plus supplement) and 800 international units of vitamin D daily are advised.
• Although the optimal intake (diet plus supplement) has not been clearly established in premenopausal women or in men with osteoporosis, 1000 mg of calcium (total of diet and supplement) and 600 international units of vitamin D daily are generally suggested

Reference:

1. www.uptodate.com
2. https://www.ncbi.nlm.nih.gov/pubmed/23440163
3. http://www.nature.com/bonekeyreports/2014/