A year ago this month, I briefly summarized 3 studies by Dr. Mark Bolland, all published in the British Medical Journal suggesting a link between calcium and heart disease. While none were large scale randomized controlled trials (RCTs) designed to look specifically at the cause & effect relationship (if any) between the two, the trend is certainly troubling. On the other hand, one could also make a case for conspiracy since only one author and journal pushed this "agenda".
Well, it looks like that conspiracy theory just took a hit as two studies were published online ahead of the June 15th print edition in Heart, authored by others than Bolland. Howevever, the conspiracy theory didn't come crashing down completely since neither were RCTs and Heart is part of the BMJ family. And instead of asking an unbiased individual to comment and editorialize on these two studies, Bolland co-authored the editorial. Still, this combination of 2 new trials in support of the trend makes for interesting cocktail hour conversation.
For instance, in the Heidelberg cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC-Heidelberg or EPIC-H), 23,980 participants avg 50yo at outset were followed for 11yrs after which the authors noted no association between total & dairy calcium intake vs cardiovascular events. On the other hand, they noted an 86% increase risk of myocardial infarction in those participants who took calcium supplements. However, they were unable to determine the inflection dose at which point risk increased nor the effect of vitamin D on risk.
In the smaller & shorter KAROLA study, 1,206 survivors of a recent cardiovascular event were followed for 8yrs, after which the authors concluded that higher baseline serum calcium levels were associated w/higher all-cause mortality in those w/pre-existing heart disease.
So what now? Remember that association is not causation. These two latest non-Bolland articles published by a journal in the BMJ family support finding a link between calcium levels and cardiovascular events & all-cause mortality. While I would rather evaluate the findings of an RCT demonstrating cause & effect, I'll settle for the latest two studies extending the trend from 12 months ago. In the meantime, I'm going to shift my total calcium intake from supplements to dairy/dietary.