Vitamin D Plus Calcium Supplementation May Not Modify Atrial Fibrillation Risk

Calcium pills
Calcium pills
Baseline serum 25(OH)D level was not predictive of long-term incident atrial fibrillation risk.

The following article is part of conference coverage from the 2018 AHA Scientific Sessions in Chicago, Illinois.The Cardiology Advisor’s staff will be reporting breaking news associated with research conducted by leading experts in cardiology. Check back for the latest news from AHA 2018.

CHICAGO — Supplementation with calcium and vitamin D had no effect on the incidence of atrial fibrillation (AF) in patients enrolled in the Women’s Health Initiative, although there was a suggestion that supplementation could be protective in patients with severe vitamin D deficiencies, according to research presented at the Scientific Sessions of the American Heart Association, held November 10-12.

Researchers in this large, randomized trial performed a secondary data analysis of the Women’s Health Initiative to evaluate the efficacy of supplementation with vitamin D and calcium for the prevention of atrial fibrillation.

Trial participants were randomized to either receive a placebo or 1000 mg calcium with vitamin D3 400 IU/day. A subset of participants was evaluated for baseline levels of serum 25-hydroxyvitamin D [25(OH)D]. Incident AF was ascertained by linking participants to Medicare claims.

Among the 16,801 trial participants with Medicare data available, 1453 (8.6%) developed incident atrial fibrillation during an average span of 4.5 years.

No significant difference was found in rates of incident atrial fibrillation between the supplementation and placebo groups (hazard ratio [HR], 1.02 for calcium/vitamin D vs placebo; 95% CI, 0.92-1.13).

Although supplementation did appear to offer some protection for patients who were severely vitamin D deficient (defined as <10 ng/mL 25(OH)D), this suggestion was not statistically significant (HR, 0.72; 95% CI, 0.31-1.66).

After adjusting for confounders such as body mass index, age, diabetes, hypertension, and baseline intake of vitamin D, no significant association was found between baseline levels of 25(OH)D and incident atrial fibrillation (HR, 0.98 for lowest vs highest quartile; 95% CI, 0.72-1.32).

Related Articles

Study investigators conclude that “while there was a suggestion that supplementation may be protective against AF in the most vitamin D-deficient subgroup, this did not reach statistical significance. We also found that baseline serum 25(OH)D level was not predictive of long-term incident AF risk.”

For more coverage of AHA 2018, click here.


Boursiquot BC, Larson JC, Shalash OA, Viotlins MZ, Soliman EZ, Perez MV. Vitamin D plus calcium supplementation and risk of atrial fibrillation. Presented at: AHA 2018; November 10-12, 2018; Chicago, Illinois. Abstract #1087.