Largest Study Yet Links Low Vitamin D to Heart Risk

We’ve previously discussed the role of vitamin D in diabetes. Now, a large new study from scientists at Copenhagen University Hospital in Denmark has provided strong evidence that there is a link between low levels of vitamin D and cardiovascular conditions such as heart disease, heart attack, and early death.

The researchers looked at vitamin D levels in 10,170 men and women from the Copenhagen City Heart Study from 1981 to 1983. Comparing the 5% of people with the lowest levels to the 50% of people with the highest levels, they found that those with the lowest levels of vitamin D had a 40% increased risk of ischemic heart disease, a 57% increased risk of early death, a 64% increased risk of heart attack, and an 81% increased risk of fatal ischemic heart disease or heart attack.

To determine the validity of this finding, the researchers then performed a meta-analysis (analysis of data from several clinical trials) of all previous population-based research looking into the association between vitamin D levels and the risk of ischemic heart disease and early death. They first performed an analysis using the 17 studies they had identified, then performed another analysis after adding their own study. In both analyses, the risk of ischemic heart disease was increased by 39% and the risk of early death was increased by 46% for the 25% of people with the lowest levels of vitamin D compared to the 25% of people with the highest levels of the vitamin.

Although the data don’t prove cause and effect, the researchers believe that recommendations regarding exposure to the sunlight, the best source of vitamin D, should be modified.

“The cheapest and easiest way to get enough vitamin D is to let the sun shine on your skin at regular intervals. There’s been a lot of focus on trying to avoid people getting too much sun, but maybe this has not been balanced. Cardiovascular disease kills many more people than skin cancer does. [However,] it is, of course, still important to avoid getting sunburned,” said lead study author Børge G Nordestgaard, MD, DMSc. The researchers do not currently recommend taking vitamin D supplements, noting that “we need evidence that this is beneficial first.”

The researchers caution that more data is needed to determine whether low vitamin D levels directly lead to cardiovascular conditions or if low vitamin D levels are a marker for overall poor health.

To learn more about the research, read the article “Largest epidemiologic study to date links low vitamin D to CVD risk” or see the study’s abstract in the journal Arteriosclerosis, Thrombosis, and Vascular Biology. And for more information about vitamin D, see diabetes dietitian Amy Campbell’s three–part series, “Vitamin D: Is It a Miracle?”