Clinical Focus ›› 2024, Vol. 39 ›› Issue (4): 325-331.doi: 10.3969/j.issn.1004-583X.2024.04.005

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Bidirectional Mendelian randomization study of causality between body mass index and type 2 diabetes in a European population

Sun Hui1, Liu Haiying2, Ren Junhao1, Li Jinxia1()   

  1. 1. Clinical Laboratory Center, Xi'an International Medical Center Hospital, Xi'an 710000, China
    2. Xi'an Changan District Health and Family Planning Comprehensive Supervision, Xi'an 710000, China
  • Received:2023-10-09 Online:2024-04-20 Published:2024-06-27
  • Contact: Li Jinxia, Email: 94396012@qq.com

Abstract:

Objective The causal association between body mass index (BMI) and type 2 diabetes mellitus (T2DM) was evaluated by bidirectional Mendelian randomization (MR). Methods Statistical data were pooled using the publicly available Genome-wide association study (GWAS). A total of 461460 cases of BMI and 655666 cases of T2DM were obtained. Totally 373 Single Nucleotide Polymorphisms (SNPs) genetic variations closely related to T2DM were selected as forward instrumental variables, and 118 SNPs were selected as reverse instrumental variables. Inverse variance weighted (IVW), Weighted median (WME), MR-Egger, Simple mode, and weighted mode were used for two-way MR analysis, and odds ratio (OR) values were used to evaluate the causal relationship between BMI and T2DM. The heterogeneity test, pleiotropy test, and leave-one-out method were further used for sensitivity analysis to evaluate the robustness and reliability of the results. Results IVW showed a significant positive correlation between BMI and the incidence of T2DM, OR was 2.88, 95% confidence interval (CI) was 2.66-3.12, P value was 5.37e-87. Other methods showed similar cause-and-effect relationships. In addition, horizontal pleiotropy was not observed by the horizontal pleiotropy test (P=0.25). Reverse MR analysis did not observe reverse causality between BMI and T2DM. Conclusion There may be a positive causal relationship between BMI and T2DM.

Key words: type 2 diabetes mellitus, Mendelian randomization, body mass index, causal relationship

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