New study links excessive amounts of vitamin D to onset of atrial fibrillation

New study links excessive amounts of vitamin D to onset of atrial fibrillation

SALT LAKE CITY - While previous studies have linked vitamin D deficiency to an increased risk for cardiovascular disease, new research at the Intermountain Medical Center Heart Institute shows that too much vitamin D can lead to the onset of a dangerous heart condition known as atrial fibrillation.

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 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).

Patients with vitamin D levels in the normal range were compared with other groups to assess their risk of developing atrial fibrillation. In patients with low, low-normal, normal and high-normal levels of vitamin D there was no increased risk of atrial fibrillation. However, in those with excess levels of vitamin D there was a significant increased risk of atrial fibrillation. Atrial fibrillation risk was two and a half times greater in patients with excess levels of vitamin D compared to those with normal levels.

Intermountain Medical Center

12 Replies

  • Interesting. No one in the part of the country where I live has excess Vit. D. We don't get nearly enough sunshine here in Pennsylvania and we are, as a population, Vit D. deficient. Since milk is fortified with Vit D, and the milk protein, casein is implicated in heart disease and tumor production, it makes me wonder if those in the study were huge consumers of milk? As always, food for thought.

  • I expect it depends on what sort of atrial fib. a person has also. Mine has been congenital faults in the node & pathways- extra AV node ablated.

    Though I am not very knowledgeable, I guess, this condition being electrical, many things can set it off for different people! We are warned not to take too much vitamin D in tablet form.

    Just shows though, its best to purchase things like milk as nature makes it - & organic too if possible.

  • I have to say like SRMGrandma, none of us in the UK suffer from a surfeit of Vitamin D, I remember sunny days, we get about 10 a year I should think :)

    In fact most of us in the UK suffer from a lack of Vitamin D, so I suspect they need to research this one a little more.

    Be well


  • They probably don't need to do any more research!!!! Assuming it is true it is merely down to "it is a statistic / fact that has no relevance to us in the UK!!!!"

    Certainly more than 10 sunny days this year!!!!

  • Sadly a lot of people in the UK self medicate with Vit D without researching safe dosages properly

  • Interesting. Hadn't heard spite of its coming from the location where my EP is located (and where my ablation was done). My doctor puts out a weekly blog about healthy choices, too! I'll be seeing him next month for my six month and will ask about it.

  • I have been far more worried about low Vit D and take a supplement, most people in Northern Europe will be Vit D deficient but as the goalposts are constantly moving as to what a 'good' level would be, how would we know?

    Too many research papers contributing very little other than 'linking' variables.

  • And my GP in South Africa says that most people in this country are also Vit D deficient in spite of the sunshine, so many people take supplements.

  • Interesting, I have osteoporosis and for years took calcium and vitamin D supplement.

    Now I have AF and don't take those pills any more, go figure? (how modern).

  • You read of so many different studies claiming this and that is good or bad for you I wonder if just reading them causes tensions which itself is not health promoting.

  • This "New Study" is not actually new at all - the original paper was published in 2011. A later study "the Rotterdam Study", did not find an association between AF and Vit D levels. See

    Assuming the American study was a real result and not a statistical quirk, it could be because US Vit D is in the form of D2 whereas European Vit D is D3. D2 is considered to be more toxic.

  • Thanks. Extremely helpful extra information.

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