Study finds vitamin D deficiency associated with increased risk for atrial fibrillation

Key takeaways:

• Vitamin D deficiency — less than 20 ng/mL — was linked to an increased risk for atrial fibrillation, although more study is needed.
• Every increase of 10 ng/mL of vitamin D resulted in a 5% risk decrease.

Vitamin D deficiency was associated with a marginally increased risk for atrial fibrillation, and increases in serum vitamin D were linked to a decreased risk, according to the results of a meta-analysis.

“In recent years, vitamin D has been hypothesized to be linked with cardiovascular diseases through its effect on inflammation or renin-angiotensin-aldosterone,” Xiaoli Ding, from the First Affiliated Hospital of Gannan Medical University in China, and colleagues wrote. “Therefore, vitamin D may be one premium option for the prevention or treatment of [atrial fibrillation (AF)] if its beneficial effects on AF risks are confirmed.”

The researchers conducted a systematic review and meta-analysis of several studies published between 2005 to 2022. Of these, five were prospective cohorts that reported on associations between serum vitamin D and AF incidences.

The remaining two studies — a randomized control trial (RCT) and a nest-case control study — examined the effects of vitamin D supplementation on AF incidence.

Ding and colleagues found that vitamin D deficiency — defined has having levels of less than 20 ng/mL — was associated with increased AF incidence (HR = 1.12; 95% CI, 1.005-1.25).

In contrast, each 10 ng/mL increase in serum vitamin D was associated with a 5% decreased risk for AF (HR = 0.95; 95% CI, 0.93-0.97).

There was ultimately no significant association between vitamin D insufficiency and AF incidence, and evidence on vitamin D supplementation was found to be conflicting.

Ding and colleagues explained that although the relationship between vitamin D and AF is still not fully understood, “it is possible that vitamin D deficiency may impair the IL-31/IL-33 axis favoring myocardial inflammation and AF development, which needs further investigation.”

There were several limitations in the study. The researchers noted that because the data were observational, potential bias or confounders could not be ruled out.

Additionally, “vitamin D levels could be affected by several factors (eg, parathyroid hormone, calcium level, lifestyle, diet and seasonal variation), which limits the findings,” they wrote.

Ding and colleagues concluded that more research from RCTs is needed.