A recent study published in the New England Journal of Medicine examining the effect of calcium and vitamin D supplements on bone health found little evidence that these two nutrients prevented hip fractures in postmenopausal women.
The study, part of the long-term Women�s Health Initiative trial involving more than 36,000 study women aged 50 to 79, assigned half of the women to receive two calcium pills daily, each containing 500 mg calcium and 200 IU of vitamin D. The other half of the participants received a placebo.
After 7 years, women taking the calcium supplement had an increase in bone density of 1 percent compared to the placebo group. While women receiving the calcium supplement were 12 percent less likely to suffer a hip fracture, this finding was not statistically significant.
While these findings may be discouraging, certain limitations of the study should be noted. First of all, it may be that women at higher risk for osteoporosis may experience a greater benefit from calcium and vitamin D supplements. Secondly, it may be that greater levels of vitamin D are needed to protect bones from fracture. In this latest study, participants received relatively low levels of vitamin D (200IU). The Osteoporosis Society of Canada advises adults over 50 to consume 800 IU a day.
There is also the compliance factor to consider. At the end of the study, 76% of the women in the treatment group were still taking their calcium pills, but only 59% were taking the intended twice-daily dose. When the researchers analyzed the results for women who were most compliant with their calcium pills, they found the risk of hip fracture reduced by a significant 29 percent in these women compared to the placebo group.
Calcium and vitamin D supplements also appeared more effective among older women. Women aged 60 or older had a significant 21 percent reduction in hip fractures - four fewer hip fractures per 10,000 women per year.
Despite the limitations of this study, the potential benefits of calcium and vitamin D supplements cannot be ignored - especially for older women. Women (and men) should continue to consume adequate intakes of calcium and vitamin D from their diet, and supplements if needed, as well as engage in weight-bearing and strength-training exercises that may reduce the risk of falls and fractures.
The study, part of the long-term Women�s Health Initiative trial involving more than 36,000 study women aged 50 to 79, assigned half of the women to receive two calcium pills daily, each containing 500 mg calcium and 200 IU of vitamin D. The other half of the participants received a placebo.
After 7 years, women taking the calcium supplement had an increase in bone density of 1 percent compared to the placebo group. While women receiving the calcium supplement were 12 percent less likely to suffer a hip fracture, this finding was not statistically significant.
While these findings may be discouraging, certain limitations of the study should be noted. First of all, it may be that women at higher risk for osteoporosis may experience a greater benefit from calcium and vitamin D supplements. Secondly, it may be that greater levels of vitamin D are needed to protect bones from fracture. In this latest study, participants received relatively low levels of vitamin D (200IU). The Osteoporosis Society of Canada advises adults over 50 to consume 800 IU a day.
There is also the compliance factor to consider. At the end of the study, 76% of the women in the treatment group were still taking their calcium pills, but only 59% were taking the intended twice-daily dose. When the researchers analyzed the results for women who were most compliant with their calcium pills, they found the risk of hip fracture reduced by a significant 29 percent in these women compared to the placebo group.
Calcium and vitamin D supplements also appeared more effective among older women. Women aged 60 or older had a significant 21 percent reduction in hip fractures - four fewer hip fractures per 10,000 women per year.
Despite the limitations of this study, the potential benefits of calcium and vitamin D supplements cannot be ignored - especially for older women. Women (and men) should continue to consume adequate intakes of calcium and vitamin D from their diet, and supplements if needed, as well as engage in weight-bearing and strength-training exercises that may reduce the risk of falls and fractures.
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