Widespread daily use of calcium and vitamin D supplements by older adults for bone health provides little to no meaningful protection against falls or broken bones, a major review published in The BMJ suggests.
The findings could prompt a significant re-evaluation of long-standing clinical advice and regulatory recommendations concerning these popular supplements.
Falls are a considerable health concern for the elderly, with nearly one in three adults aged 65 and over experiencing a fall each year. Such incidents can lead to fractures, chronic pain, a loss of independence, reduced quality of life, and in some cases, the need for residential care. Consequently, identifying effective preventative strategies for falls and fractures remains a critical public health objective.
Calcium is a primary structural component of bone, while vitamin D plays a crucial role in calcium absorption and bone metabolism. This established link has historically led to a common association between these nutrients and robust bone health.
However, previous evidence reviews have yielded inconsistent results, particularly concerning whether calcium or vitamin D taken alone significantly reduces fracture risk. Uncertainty has also persisted regarding the combined effect of both supplements and vitamin D's ability to reduce falls.
Despite these unanswered questions, vitamin D supplements, often with calcium, are frequently recommended by clinicians, included in guidelines, and endorsed by regulatory agencies for maintaining bone health. Prescriptions for these supplements have also seen a substantial increase in recent years.
To provide a clearer picture, researchers in Canada undertook a comprehensive examination of evidence from 69 randomised controlled trials. These trials involved a total of 153,902 adults, comparing the effects of calcium supplements, vitamin D supplements, or a combination of the two against a placebo or no treatment.
Randomised controlled trials are considered among the most robust methods for evaluating treatment effectiveness, as participants are randomly assigned to different groups, helping to minimise the influence of other variables. The research team focused specifically on the supplements' potential to reduce fractures and falls. While the quality of individual studies varied, the team rigorously assessed the risk of bias and the certainty of the evidence using established research methodologies.
After establishing thresholds for what would constitute a clinically meaningful benefit, the researchers concluded that there was little to no effect on the likelihood of experiencing any fracture.
This conclusion was supported by moderate certainty evidence from 11 trials involving 9,067 participants for calcium supplements. For vitamin D supplements, high certainty evidence from 36 trials involving 92,045 participants led to a similar conclusion.
When calcium and vitamin D were taken together, high certainty evidence from 15 trials involving 51,126 participants also indicated little to no meaningful effect on fracture prevention.
The same general pattern was observed when the researchers analysed specific outcomes, including hip fractures and falls. Calcium, vitamin D, and combined supplementation consistently showed little to no effect, with most of this evidence rated as moderate to high certainty.
The researchers acknowledge that some aspects of their analysis were based on relatively small numbers of trials or participants, suggesting that these particular findings should be interpreted with caution. They also highlighted that the conclusions may not be universally applicable, especially for individuals with specific bone disorders or those undergoing treatment for osteoporosis, who may have distinct needs.
Nonetheless, the overall conclusions were strengthened by the consistency of the results, which largely held true even after accounting for various factors such as age, sex, previous fractures, previous falls, and average dietary calcium intake.
Based on their findings, the researchers assert that the available evidence "does not support routine supplementation with calcium or vitamin D, or combined supplementation to prevent fractures and falls." They further suggest that clinicians, guideline panels, and regulatory agencies "should re-evaluate their general recommendations for calcium and vitamin D supplementation in light of current evidence."
In a linked editorial, accompanying the review, other researchers noted that more rigorous and adequately powered trials are still needed to determine if supplementation might benefit individuals at particularly high risk.
For the immediate future, the editorial authors propose redirecting more attention and funding towards preventative strategies that have already demonstrated meaningful benefits in preventing falls and related injuries. These include balance training and resistance exercise, which are known to improve strength, stability, and overall physical function.
Programmes that integrate multiple approaches may also prove effective. Such programmes could incorporate exercise, assessments of environmental hazards contributing to falls, and educational components tailored to an individual's specific risk profile.
Collectively, the findings underscore that preventing falls and fractures in older adults may require a more multifaceted approach than simply incorporating calcium or vitamin D supplements into a daily routine.
