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Calcium and vitamin D supplements should not be used routinely in non-institutionalised elderly people. The absolute benefit of calcium and vitamin D supplements in terms of fracture reduction is low. There is evidence of significant benefit in people at risk of deficiency, particularly institutionalised individuals. Calcium and vitamin D supplements should be offered to people taking osteoporosis treatments if their dietary calcium intake is less than 1300 mg per day.
Calcium and vitamin D supplements have been widely used in an attempt to prevent bone loss and prevent fractures in postmenopausal women and older men. However, evidence indicates that the absolute benefit of these treatments in terms of fracture prevention for non-institutionalised individuals is low and considerably less than that seen with licensed osteoporosis treatments. There could be benefit for those who may be deficient; particularly institutionalised individuals. The US Preventive Services Task Force has recommended against routine calcium and vitamin D supplementation in non-institutionalised elderly people.1
The target calcium intake from dietary sources and supplements should be 1000 mg per day for adults, rising to 1300 mg per day for women older than 50 years of age and men older than 70 years of age. Vitamin D from sunlight exposure (avoiding periods of high ultraviolet-radiation intensity such as in the middle of the day) and supplements should ensure 25-hydroxyvitamin D (25-OH D) levels >50 nmol/L. If vitamin D supplements are required, a dose of 800–1000 IU per day is usually sufficient, although higher doses are needed in some people to achieve target levels. Dietary calcium intake is often suboptimal in the elderly, especially institutionalised individuals.
Calcium and vitamin D supplements work by reducing secondary hyperparathyroidism and reducing bone turnover.
Bone mineral density (BMD) is also increased by calcium and vitamin D, but this effect appears to be modest. Calcium and vitamin D are not available on the Pharmaceutical Benefits Scheme (PBS) but are recommended for people likely to have insufficient intakes. This is particularly important for those taking other osteoporosis therapies.
Calcium supplements are available in two common forms: calcium carbonate and calcium citrate. Calcium tablets typically contain 250–600 mg of elemental calcium. The most commonly available type of vitamin D supplement is vitamin D3 or cholecalciferol. Vitamin D3 elevates serum 25-OH D concentrations more than vitamin D2 or ergocalciferol, and is also more reliably measured by commercially available assays. Currently available doses of vitamin D range from 400–1000 IU, available as capsules, tablets or liquid formulations.
Side effects and potential harms
Calcium supplements modestly increase the risk of renal calculi. Calcium supplements can also cause abdominal bloating and constipation. It has been reported that there could be an increased risk of myocardial infarction (MI) with calcium supplements, but not all studies support this conclusion. Calcium and vitamin D supplements do not increase the risk of death and some studies suggest a small reduction in the risk of death.
Clinical toxicity is uncommon with vitamin D, even in high doses. Single doses of up to 500,000 IU are tolerated without causing hypercalcaemia or hypercalciuria. However, the use of higher-dose formulations of vitamin D in elderly populations has been associated with an increased risk of falls.
Practical tips and precautions
- In otherwise healthy non-institutionalised individuals, the relative reduction in fracture risk with calcium and/or vitamin D supplementation alone is small and may be associated with some adverse events. As such, these should not be considered routinely in healthy people or as first-line treatments for people with osteoporosis.
- Target calcium intake should be 1000 mg per day in adults and 1300 mg per day in postmenopausal women and older men, ideally from dietary sources. Where this cannot be achieved, a supplement of 500–600 mg calcium is appropriate.
- Vitamin D from sunlight exposure (avoiding the middle of the day) and supplements should ensure that 25-OH D levels are above 50 nmol/L.
- Calcium citrate does not need to be taken after meals like calcium carbonate, as it does not require an acid environment to be optimally absorbed. Calcium and vitamin D supplements may be taken at any time of the day.
- Calcium and vitamin D supplements are more likely to be effective in reducing fracture risk when given in combination to individuals who are deficient. The majority of studies demonstrating efficacy of other osteoporosis treatments have been conducted in the setting of concurrent calcium and vitamin D supplementation.
There is mixed evidence for the impact of oral calcium and vitamin D supplementation on the reduction of fractures outside institutionalised settings. Overall, the reductions in fracture risk are small in absolute terms with relatively large numbers of people needed to be treated to prevent fractures.
A recent systematic review reported on the effect of calcium supplements (with or without vitamin D) in older adults.2 Calcium supplementation (20 trials, 58,573 individuals) significantly reduced the risk of any fracture (relative risk [RR]: 0.89, confidence interval [CI]: 0.81–0.96). The risk of vertebral fracture was also reduced (RR: 0.74–1.00) but the risk of hip fracture was not. Only a small number of randomised controlled trials (RCTs) examined the effect of changes in dietary calcium intake on fracture risk and thus no conclusions could be drawn.
Another systematic review reported on the effect of vitamin D supplements (with or without calcium) in older adults.3 Vitamin D supplementation alone was not associated with a reduction in hip fractures (RR: 1.2, CI: 0.98–1.29), or any new fracture (RR: 1.03, CI: 0.96–1.11). Vitamin D plus calcium supplements resulted in a small reduction in hip fracture risk (RR: 0.84, CI: 0.74–0.96). In community-based individuals this translates into one fewer hip fracture per 1000 people treated per year, whereas for institutionalised individuals, supplementation would result in nine fewer hip fractures per 1000 people treated per year. Vitamin D plus calcium supplementation was associated with a small reduction in the risk of any fracture (RR: 0.95, CI:
The safety of calcium and/or vitamin D supplements has been examined in several meta-analyses (MAs).3-5
In a recent Cochrane review, the risk of renal insufficiency or calculi was found to be increased by vitamin D and calcium supplements (RR: 1.17, CI: 1.03–1.34).3 There was also an increased risk of gastrointestinal symptoms (RR: 1.04, CI: 1.00–1.08). The risk of cardiac events has also been examined, but despite being based on datasets from the same RCTs, different MAs have drawn different conclusions. One MA found an increased risk of MI (RR: 1.24, CI: 1.07–1.45) and stroke (RR: 1.15, CI: 1.00–1.32) in people taking calcium supplements with or without vitamin D.5 Another MA found no association with MI (RR: 1.08, CI: 0.92–1.26) or coronary heart disease in general.4 MAs indicate that calcium supplements with or without vitamin D have no effect on overall mortality, and the combination of calcium and vitamin D has been found to reduce the risk of death in one MA.6
RCTs have evaluated the effectiveness of higher-dose vitamin D supplements to reduce the risk of falls in individuals at high risk of falling. The use of high-dose oral vitamin D increased the risk of falls rather than reduced it.7,8 One recent trial that compared the effect of 24,000 IU once per month to 60,000 IU once per month found that the higher dose was associated with a significantly increased incidence of falls.8