The study involved 132,000 patients who were placed into categories to compare levels of vitamin D: low (less than 20 nanograms per decilter), low/normal (21-40 ng/dl), normal (41-80 ng/dl), high/normal (81-100 ng/dl), and excess (more than 100).
The data revealed that those who consumed too much of vitamin D were two and a half times more likely to develop atrial fibrillation as compared to those taking normal levels.
The researchers seek to identify safe levels for vitamin supplements.
Lead researcher T. Jared Bunch from Intermountain Medical Center Heart Institute said the data is significant as many Americans take vitamin supplements for better health.
"Our goal is to determine a safe dose and usage range so patients can understand what amount is healthy, and what amount may be toxic," Bunch added.