Exploring the Causality Between Body Mass Index and Sepsis: A Two-Sample Mendelian Randomization Study

Objective: Observational epidemiological studies have shown a link between obesity and sepsis, but any causal relationship is not clear. Our study aimed to explore the correlation and causal relationship between body mass index and sepsis by a two-sample Mendelian randomization (MR).Methods: In large sample genome-wide association studies, single-nucleotide polymorphisms related to body mass index were screened as instrumental variables. Three MR methods, MR-Egger regression, weighted median estimator, and inverse variance-weighted, were used to evaluate the causal relationship between body mass index and sepsis. Odds ratio (OR) and 95% confidence interval (CI) were used as the evaluation index of causality, and sensitivity analyses were conducted to assess pleiotropy and instrument validity.Results: By two-sample MR, the inverse variance weighting method results suggested that increased body mass index was associated with an increased risk of sepsis (odds ratio 1.32; 95% CI 1.21-1.44; p = 1.37 x 10(-9)) and streptococcal septicemia (OR 1.46; 95% CI 1.11-1.91; p = 0.007), but there was no causal relationship with puerperal sepsis (OR, 1.06; 95% CI, 0.87-1.28; p = 0.577). Sensitivity analysis was consistent with the results, and there was no heterogeneity and level of pleiotropy.Conclusion: Our study supports a causal relationship between body mass index and sepsis. Proper control of body mass index may prevent sepsis.

Automated summary

This study used a two-sample Mendelian randomization to explore the correlation and causal relationship between body mass index (BMI) and sepsis. The results showed that increased BMI was associated with an increased risk of sepsis, supporting a causal relationship. Proper control of BMI may help prevent sepsis.