Calcium supplements reduced fracture risk

Researchers recommend 1,200 mg of calcium and 800 IU of vitamin D per day in people aged 50 and older.

Issue: October 2007

Calcium supplementation was associated with a 12% reduction in osteoporotic fracture risk in people aged 50 years and older, according to a study published in The Lancet.

Australian researchers conducted a meta-analysis to evaluate the effects of calcium, alone or in combination with vitamin D on fracture risk and osteoporotic bone loss.

“While calcium supplementation has been widely available and has been used by some physicians, the evidence on its efficacy has been unclear,” Benjamin M. P. Tang, MD, research associate, University of Western Sydney, told Endocrine Today.

“Osteoporotic fractures are expected to increase worldwide as the population ages. There is a one in six lifetime risk for a fracture in women aged 50 years and older, slightly less in men, but the gender gap narrows with increased age,” he said.

The study confirms that calcium can help prevent fractures and bone loss, according to Tang.

Effects on bone loss

The researchers analyzed 29 randomized trials (n=63,897; 92% women; mean age, 67.8 years) conducted from January 1966 to January 2007. All trials had an average treatment period of 3.5 years. The median baseline fracture risk was 16%. In 13 trials, individuals received calcium in combination with vitamin D; in all others they received calcium supplementation only.

Fracture was an outcome in 17 trials. The calcium supplementation, with or without vitamin D, was associated with a 12% relative risk reduction for all fracture types.

Twenty-three trials reported BMD as an outcome. In those trials, calcium treatment was associated with a significant reduced risk for bone loss in the hip and in the spine.

Those who reaped the greatest risk reductions were the elderly; those living in institutions; those with a low body weight, calcium intake (<700 mg per day), or vitamin D serum concentration (<25 nmol/L); or those at a higher baseline risk than others, according to the researchers.

“The treatment effect was consistent irrespective of sex, fracture sites or history of previous fracture,” the researchers wrote. “Moreover, the treatment was similarly effective whether the person used calcium in combination with vitamin D supplementation,” which did not produce additional risk reductions compared with calcium alone.

Recommended doses

The researchers recommended a minimum dose of 1,200 mg calcium and 800 IU vitamin D per day in people aged 50 years and older.

The recommendation was made based on a separate analysis in which individuals treated with 1,200 mg calcium or more had significantly better treatment effects compared with lower doses. The results were similar for 800 IU vitamin D or more.

Overcoming poor compliance

Calcium supplementation, alone or with vitamin D, was less effective if compliance was poor, according to the researchers.

This is the first study of calcium treatment and its effects on compliance, Tang said.

“We showed that if the patients are not compliant with the medication, they potentially lose half of the benefit of the treatment,” he said.

There are several keys to overcoming compliance issues with calcium supplementation, including regular monitoring and patient education, the researchers wrote.

“Because calcium is a preventive medication, patients will not see the benefit of the treatment directly,” Tang said. “Hence, there is no incentive for them to keep up with the medication, unless patients are educated by the physicians about the risk of fractures and the medical consequences of suffering a fracture, such as pain, immobility and infection.”

Tang also provided advice to overcome other issues that may arise.

“It is difficult for people to consume sufficient amounts of dietary calcium, particularly as the dietary requirement increases with increasing age, and this coincides with an age-related reduction in the amount of food eaten,” he said. “Additionally, compliance [with taking] calcium supplements can be poor due to the gastrointestinal adverse events, particularly with calcium carbonate. Poor compliance is also compounded by the fact that taking the supplement has no perceivable effect on health and well-being, such as a reduction of symptoms.” – by Katie Kalvaitis

For more information:

Tang BMP, Eslick GD, Newson C, et al. Use of calcium or calcium in combination with vitamin D supplementation to prevent fractures and bone loss in people aged 50 years and older: a meta-analysis. Lancet. 2007;370:657-666.