Hey Feisty,

Good on you for taking the time and effort to track down information on atrial fibrillation and any possible relationship to vitamin D3...

Had lighting struck that close to me or a love one... I'd have done the same thing.

The link you posted about too much vitamin D3 causing atrial fibrillation (AF), is actually old news... circa November 2011... and it's not very accurate news at that.

You picked the results part of this article that essentially shouts "Fire" in a theater, then hands out buckets of gasoline...

Now why would anyone want to do that???

Reading a little farther in the Vitamin D Council's analysis of this study, (I've been a member of the Vitamin D Council for nearly four years and talk with them frequently), you'll find a peer review based on common sense logic and knowledge of properly constructed RCTs... 

This study and the dupes who reported on its results were apparently attempting to scare people away from taking vitamin D3...  Again... who would want to do that?  Does the term "Big Pharma" ring a bell?

Had you posted sections from further down in the Vitamin D Council's analysis of this study, you would have found the following:

"The mechanism has yet to be accounted for by the investigators of the study. And many have cited that association does not necessarily translate to causation, and in consequence, we can’t take this study too seriously."

"What is unfortunate here is the lack of perspective in the MSNBC article. This study is a victim of poor journalism. The title reads like a siren, warning all who take vitamin D to stop. Much to our dismay, we are sure they achieved this for a portion of readers. "

If you read a lot of studies and articles involving vitamin D3 like I do, you get real good at spotting poorly constructed studies as well as studies with an obvious agenda designed to scare people away from taking vitamin D3...  Again... who would want to do that?

Prospective studies using vitamin D3 as a medical intervention that have either too low a vitamin D3 dose (<2000 IU/day) and/or none of the vitamin D3 cofactors are suspect.  Similar studies of vitamin D3 that don't track serum concentrations of 25(OH)D, calcium and PTH are also suspect.

My analysis of this article (and study abstract) found the researchers did not specify the actual range of 25(OH)D serum concentrations above 100 ng/mL. Remember, 25(OH)D is only a bio-marker...

This study also failed to measure serum calcium, PTH and calcium-creatinine ratio.  Any medical researcher who really understands the pharmacokinetics of vitamin D3 would have been familiar with these lab tests and incorporate them into the study protocol.  One of the biggest findings was not reported...  there were no indications of vitamin D3 intoxication among the study cohort...

Furthermore, there was no analysis of the cohort by age group, gender, demographics or epidemiological factors with respect to the incidence of AF.

As an example, in one study, "The AF incidence rate in the age group 55–59 years was 1.1/1000 person–years, rose to 20.7/1000 person–years in the age group 80–84 years and stabilized in those aged 85 years and above. Prevalence and incidence were higher in men than in women. The lifetime risk to develop AF at the age of 55 years was 23.8% in men and 22.2% in women.

Conclusion: In this prospective study in a European population, the prevalence and incidence of AF increased with age and were higher in men than in women. The high lifetime risk to develop AF was similar to North American epidemiological data."

See Prevalence, incidence and lifetime risk of atrial fibrillation at the following link for more detail.

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If you Google the following search terms, "atrial fibrillation vitamin D3 25(OH)D" you'll find there are tens of thousands of articles and studies on this topic...  Most link AF to low vitamin D3 status...  Only a handful attempt to attribute AF to excess vitamin D3, a 25(OH)D serum concentration > 100 ng/mL... and they all point to the same 2011 study.

Back to the diagnosis of AF...  If your husband was prescribed blood thinners...  Coumadin, (warfarin) or one of the newer generation blood thinners like Pradaxa... you need to read the following link.  It discusses controlling AF without drugs.

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Take care and please keep us posted.

V/R, Batch

Hey Todd,

Thanks for the update and lab data...  Your 25(OH)D serum concentration is spot on and it confirms and validates what Dr. Robert Heaney, MD, has been saying all along.  "The average 25(OH)D response to a dose of 10,000 IU/day vitamin D3 is 80 ng/mL."

I agree with your proactive approach in raising your vitamin D3 intake for the Fall allergy season.  I've done the same thing...  Lots of leaf mold spores blowing around here in the Puget Sound area.

Take care, thanks again and please keep us posted.

V/R, Batch