Effect of Body Mass Index on Risk of Atrial Fibrillation

According to findings from a two-sample Mendelian randomization (TSMR) study published in Nutrients, a higher body-mass index (BMI) “causally increased” the risk of atrial fibrillation. The study’s authors, led by Mi Ma, undertook the analysis to further describe the causal relationship between BMI and atrial fibrillation.

Researchers reviewed 681,275 individuals in the Genetic Investigation of Anthropometric Traits (GIANT) consortium to identify BMI-associated independent genetic variants (n = 303). The team then assessed patient outcomes in genome-wide association studies encompassing 60,620 and 970,216 European subjects and controls, respectively.

The TSMR approach involved five methods to examine causal associations between BMI and atrial fibrillation—inverse variance weighted (IVW), MR-Egger regression, weighted median estimator (WME), generalized summary data-based Mendelian randomization (GSMR), and the robust adjusted profile score (RAPS).

Using the IVW method, the authors observed that “a genetically determined 1-standard deviation (SD) increment of BMI causally increased a 42.5% risk of AF (odds ratio = 1.425; 95% confidence interval, 1.346–1.509),” which they stated was consistent with the findings of the other four analysis methods.

Overall, the researchers felt their analysis provided evidence that a higher BMI did causally increase the risk of atrial fibrillation. Additionally, they proposed that this finding calls for control of BMI and obesity for the prevention of atrial fibrillation.