Too much vitamin D can lead to 2.5 times the risk of atrial fibrillation, researchers found.
To determine if there is a correlation between too much vitamin D and increased heart risk, researchers examined blood tests from 132,000 patients in the Intermountain Healthcare Center database. Results were presented at the American Heart Association Scientific Sessions in November, and appeared at the Intermountain website.
Patients did not have any known history of atrial fibrillation, and all had previously received a vitamin D assessment as part of their routine care. Patients were then placed into categories to compare levels of vitamin D: low (less than 20 ng/dL), low/normal (21-40 ng/dL), normal (41-80 ng/dL), high/normal (81-100 ng/dL), and excess (more than 100 ng/dL).
Patients with low, low-normal, normal and high-normal levels of vitamin D had no increased risk of atrial fibrillation. However, atrial fibrillation risk was 2.5 times greater in patients with excess levels of vitamin D compared to those with normal levels.
The Institute of Medicine currently advises that healthy adults should be able to take as much as 4,000 IU (international units) of vitamin D daily. But the exact amount of vitamin D to achieve normal levels is unknown and usage varies in different regions and communities, which can cause problems, said the researchers.
They encouraged physicians to ask patients about all vitamins and supplements, and that checking blood levels of vitamin D in patients who develop atrial fibrillation may help uncover the cause of the abnormal heart rhythm.
*This blog post was originally published at ACP Hospitalist*