12 Mar 2015 Blackmores Institute High blood levels of vitamin d increase risk of stroke coronary study 12 Mar 2015 Share Share on LinkedIn Share on Facebook Share on Twitter Share on Google+ Share on Pinterest News A study identifying a link between high levels of vitamin D and cardiovascular deaths, suggests that the level of vitamin D in our blood should not be too high nor to low, but, to quote Goldilocks, "just right". Research from the University of Copenhagen found that high serum vitamin D - over 100 nanomol per litre - is connected to an increased risk of dying from a stroke or a coronary. × To continue reading this article, please Log In or Sign Up for access.