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 mellitus (T2DM) remains unclear.
In this study, a network Mendelian randomization (MR) framework was applied to determine the causality between education and T2DM from summarized genome-wide association study data.
We used a network MR to identify the causality between education and T2DM and the potential metabolic risk factors [coronary heart disease (CHD), total cholesterol, low-density lipoprotein, triglycerides, body mass index (BMI), waist circumference (WC), waist-to-hip ratio, fasting insulin, fasting glucose, and glycated hemoglobin] from summarized genome-wide association study data.
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. DIAGRAM plus Metabochip consortium data were utilized for T2DM.
In the IVW method, the odds ratio (95%CI) for T2DM was 0.392 (0.263-0.583) per standard deviation increase (3.6 years) in education, without heterogeneity or horizontal pleiotropy. Education was genetically associated with CHD, triglycerides, BMI, WC, and waist-to-hip ratio in the discovery phase, yet only the results for CHD, BMI, and WC were confirmed in the replication data. Moreover, BMI was positively associated with T2DM.
Short education was found to be associated with increased T2DM risk. BMI might serve as a potential mediator between them.
For most developing countries, the majority of the population receive short education years. Longer education time is recommended as is a BMI control program, for public T2DM prevention.