You might think it wouldn’t be difficult to figure out whether vitamin D and calcium supplements help prevent hip fracture in older people. You would be wrong. For the last twenty or thirty years, researchers have asked this question and have reached differing conclusions. The last time I blogged about the question, a study had come out showing that vitamin D matters, at least when taken in sufficient quantities (800 units a day). Since then, I’ve been dutifully taking the suggested amount of vitamin D. I still take TUMS, too, to get some extra calcium, but I haven’t been as conscientious about this because the data is weaker. Now, JAMA has published an article that looked specifically at community-dwelling older people (that is, it excludes nursing home residents)—and concluded that neither calcium not vitamin D nor the combination of them has any discernible effect in preventing hip fractures.
Granted, this study is a “meta-analysis,” a study of studies, rather than the gold standard, a randomized controlled trial. Granted, this study looks primarily at hip fractures, arguing that they have the greatest effect on quality of life (and health care costs), though plenty of older people manage to break a wrist or suffer from back pain due to compression fractures without breaking a hip. Maybe the real reason that the individual studies that form the basis of the current analysis have not consistently any benefit from vitamin D or calcium is that few people actually take the drugs that they say they’re taking. Whatever the explanation for the findings, the hard, cold reality is that the current research is another blow, a particularly powerful blow, against the view that diet can prevent fractures in older people.
Here it is, New Year’s Day. Should I resolve to stop taking vitamin D and calcium? It would be an exceptionally easy resolution to stick to. It’s tempting. I might make the irrational decision to keep taking vitamin D until the bottle that I currently have is empty. Or I might wait until I see my primary care physician for my next routine appointment and do whatever she advises. But here’s what I think I will do: I will continue taking vitamin D, knowing that it probably isn’t effective, but recognizing that it might be in light of the studies to date that have arrived at differing conclusions. I will continue taking TUMS for calcium in the same somewhat haphazard way I've been doing. As long as there is almost no down side of taking these, I’ll take them. Right now, it’s fairly inexpensive, I have no trouble swallowing the pills, I’m not taking other medications, and I have had no side effects of the vitamin or calcium. This is the key point: there are almost no adverse effects of vitamin D; ditto for calcium when taken in moderation. How often can we say that about a medical intervention?