Calcium and Vitamin D

Anti-osteoporotic drugs and calcium/vitamin D supplementation

In patients receiving anti-osteoporotic drugs, calcium and vitamin D supplements should be prescribed as co-therapy.

It is important to stress that all studies which have investigated the efficacy of bisphosphonates, SERMs, calcitonin, teriparatide, strontium ranelate or denosumab were performed with patients adequately supplemented with calcium and vitamin D. No demonstration of the anti-fracture efficacy of these compounds has been obtained without concomitant supplementation in calcium and vitamin D.

For general information on calcium and vitamin D and their role in osteoporosis prevention, together with other lifestyle factors, please see Prevention

Some recent research on calcium and vitamin D

Healthy children

A quantitative systematic review of calcium supplementation in healthy children concluded that calcium supplementation provided only a small effect on bone mineral density at the total body and upper limb. This effect persisted after the end of supplementation only at the upper limb. When analysing separately female children, point estimates were greater at all sites showing significant increases at the femoral neck, total body at the end of supplementation and after withdrawal of supplementation (1)

Postmenopausal women and elderly subjects

Available evidence does not support a role for calcium and vitamin D alone in prevention of osteoporotic fractures except in the institutionalized elderly population (2, 3). In the home-dwelling population, studies of native vitamin D have produced conflicting results which may be related to the dose of vitamin D and calcium supplementation. Vitamin D at the dose of 700 to 800 IU with 1000 to 2000 mg calcium daily significantly reduced the incidence of non-vertebral fractures by 23 %, including a significant 26 % decrease in the risk of hip fracture (4,5). In contrast, a lower dose of vitamin D (400 IU daily) did not reduce fracture risk (6). In addition, higher doses of vitamin D that result in serum 25OHD >60 nmol/L may decrease the risk of falls (7).

Active metabolites of vitamin D (1α-hydroxycholecalciferol [1α(OH)D], 1α,25(OH)2D) are used for the treatment of osteoporosis in certain countries. Two meta-analyses show that both forms of vitamin D decrease significantly the incidence of fragility fractures, at least in patients who were not treated with glucocorticoids (8,9). However, these results are partly based on the studies of suboptimal methodological quality (9), thus, the evidence base for the anti-fractures efficacy of the active metabolites of vitamin D remains to be proven.

Compliance issues
The WHI trial also highlighted the need for ensuring patient compliance with supplementation. Similar conclusions were recently published in a five-year, double-blind, placebo-controlled study. It has been demonstrated that supplementation with calcium carbonate tablets supplying 1200 mg/day was shown ineffective in preventing clinical fractures in ambulatory elderly women (mean age 75 years), owing to poor long-term compliance, although it was effective (-34%) in those patients who were compliant (who took 80% or more of their tablets) (10).

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