Published online Mar 15, 2021. doi: 10.4239/wjd.v12.i3.261
Peer-review started: July 27, 2020
First decision: November 4, 2020
Revised: November 10, 2020
Accepted: December 23, 2020
Article in press: December 23, 2020
Published online: March 15, 2021
The causality between education and type 2 diabetes (T2DM) remains unclear.
To identify the causality between education and T2DM and the potential metabolic risk factors [coronary heart disease (CHD), total cholesterol, low-density lipoprotein, triglycerides (TG), body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR), fasting insulin, fasting glucose, and glycated hemoglobin] from summarized genome-wide association study (GWAS) data used a network Mendelian randomization (MR).
Two-sample MR and network MR were performed to obtain the causality between education-T2DM, education-mediator, and mediator-T2DM. Summary statistics from the Social Science Genetic Association Consortium (discovery data) and Neale Lab consortium (replication data) were used for education and DIAGRAMplusMetabochip for T2DM.
The odds ratio for T2DM was 0.392 (95%CI: 0.263-0.583) per standard deviation increase (3.6 years) in education by the inverse variance weighted method, without heterogeneity or horizontal pleiotropy. Education was genetically associated with CHD, TG, BMI, WC, and WHR in the discovery phase, yet only the results for CHD, BMI, and WC were replicated in the replication data. Moreover, BMI was genetically associated with T2DM.
Short education was found to be associated with an increased T2DM risk. BMI might serve as a potential mediator between them.
Core Tip: Genetically predicted education was negatively causally associated with type 2 diabetes (T2DM). The odds ratio for T2DM was 0.392 (95%CI: 0.263-0.583) per standard deviation increase (3.6 years) in education. Body mass index might serve as a potential mediator.