We have received many emails regarding the calcium, vitamin D and fracture report from the United States Preventative Services Task Force, often just abbreviated the USPSTF. The USPSTF is a panel of physicians and epidemiologists appointed by the US Department of Health and Human Services. They publish recommendations for a variety of different things after evaluating the effectiveness of interventions, screening and other clinical practices.
Usually, the USPSTF publishes a draft for the public to read. They then open up a one month grace period for the public to comment before they release a finalized recommendation six months later. When their recent evaluation and recommendation hit headlines last week that vitamin D and calcium cannot prevent fractures, this was actually the same report that hit headlines around June/July 2012. Our Executive Director Dr Cannell responded to the draft then and what he stated then still echoes our opinions of now.
Their report is based on data from two systematic reviews and a meta-analysis. They stated the following:
Most clinicians and researchers would agree with the first contention, that vitamin D at a dose of only 400 IU is too low to have much of an effect on fractures.
On the other hand, the second contention that vitamin D of intakes of greater than 400 IU have not been tested enough to determine its effect on fractures is disputed. In fact, Professor Bischoff-Ferrari pooled 11 randomized controlled trials and determined that intakes of 800 IU of vitamin D and greater likely reduce fracture incidence, while lower intakes do not.
For some, this was good evidence that vitamin D at higher doses reduces fractures; for others, including the USPSTF, this was not enough evidence.
Confusingly, the USPSTF released recommendations in May of 2012 that vitamin D should be taken to prevent falls, an incident in which 5-10% of the time lead to fractures.
Overall, this is a good look at why some in vitamin D research believe evidence-based medicine is doing vitamin D wrong. Evidence-based medicine is very good at guiding clinicians whether or not we should take a drug. Drugs often have single endpoints, like does the drug prevent fractures? Then health care professionals can evaluate if the benefit in fracture reduction outweighs any risks involved.
In nutrition, there are many endpoints, not just one. Vitamin D may be involved in bone health, cancer prevention, cardiovascular disease prevention, skin integrity, immunity, diabetes and more. Thus, it becomes a bit difficult and futile in trying to evaluate just one endpoint and benefit, and then make a public recommendation based upon whether there’s efficacy for that one endpoint.
In this case, the USPSTF has come off a bit schizophrenic in their recommendations of vitamin D, calling to take it for falls but not for fractures. While this is likely not their intention, the media will always spin it two ways: you must take vitamin D or you must not. And thus, you have to question whether these evaluations and recommendations are doing more harm than good.
In conclusion, a recommendation for a single endpoint – fractures – may have been unnecessary, confusing for the public and leave many astray. Can we take vitamin D for the sake of being sufficient in vitamin D and for the sake of overall health? Many organizations, including the Endocrine Society, Vitamin D Council and even the IOM, say yes, whether or not vitamin D reduces fractures, we need vitamin D for overall health.