The June 23, 2008 issue of the American Medical Association journal Archives of Internal Medicine published the discovery of Austrian and German researchers that men and women with higher serum levels of vitamin D have a reduced risk of dying from all causes as well as specifically from cardiovascular disease over a seven year period, compared with individuals whose blood levels are low.
Harald Dobnig, MD, of Medical University of Graz, Austria, and colleagues evaluated data from 3,258 participants scheduled for coronary angiography who enrolled in the Ludwigshafen Risk and Cardiovascular Health Study between 1997 and 2000. Serum levels of 25-hydroxyvitamin D and 1,25-dihydroxyvitamn D, which is converted from 25-hydroxyvitamin D in the body, were measured in blood samples collected prior to the angiographic procedure.
Over an average 7.7 years of follow-up, 737 deaths occurred, of which 62.8 percent were from cardiovascular causes. Approximately two-thirds of the patients were found to have low serum 25-hydroxyvitamin D levels of under 20 nanograms per milliliter. Cardiovascular risk markers, including C-reactive protein levels and interleukin 6 levels (which evaluate inflammation), oxidative burden, and cell adhesion markers, were greater among individuals with lower serum 25-hydroxyvitamin D levels than in those whose levels were higher. Participants whose serum 25-hydroxyvitamin D levels were among the lowest one-fourth of participants, at a median of 7.6 nanograms per milliliter, had an adjusted risk of dying from all causes or cardiovascular disease that was twice that of subjects whose levels were among the highest fourth at 28.4 ng/mL. When 1,25-dihydroxyvitamin D levels were evaluated, similar associations were found.
“This prospective cohort study demonstrates for the first time, to our knowledge, that low 25-hydroxyvitamin D and 1,25-dihyroxyvitamin D levels are associated with increased risk in all-cause and cardiovascular mortality compared with patients with higher serum vitamin D levels,” the authors write. "Apart from the proved effects that vitamin D has on bone metabolism and neuromuscular function, appropriate serum levels (that may also be higher than in the present investigation) are associated with a decrease in mortality. Although not proved, it seems possible that at least part of this effect may be due to lowering of a risk profile promoting atherosclerosis and preventing cardiovascular end points."
"Based on the findings of this study, a serum 25-hydroxyvitamin D level of 20 nanograms per milliliter or higher may be advised for maintaining general health," they conclude.