The aim of this study was to evaluate the association of the body mass index (BMI) categories with the risk of sudden cardiac death (SCD) in a systematic review and meta-analysis.

We systematically searched the PubMed, Embase, and Cochrane Library databases up to February 2018 for all studies reporting an association between BMI and risk of SCD. Relative risks (RRs) and 95% confidence intervals (CIs) were extracted and pooled using a random effects model.

A total of 10 studies involving 1,381,445 participants were included in the meta-analysis. Overall, compared with the risk level in normal-weight controls, being underweight was not associated with increased risk of SCD (RR = 1.20, 95% CI, 0.95-1.51; P = 0.13). In contrast, both being overweight (RR = 1.21, 95% CI, 1.08-1.35; P = 0.0008) and obesity (RR = 1.52, 95% CI, 1.31-1.77; P < 0.00001) were associated with increased risk of SCD. The association between the BMI categories and risk of SCD was stable in the sensitivity analysis in which individual studies were serially excluded.

The findings from this meta-analysis indicate that excess weight is associated with an increased risk of SCD. Further research is required to explore the underlying mechanisms.