Navigating the shifting Mendelian randomisation landscape: some observations and suggestions for editors, reviewers and investigators.

As members of the editorial board of the Journal of Epidemiology and Community Health (JECH), we have noticed a rapid increase in recent years in submissions using Mendelian randomisation (MR). While this surge reflects MR’s clear potential in epidemiological research, many manuscripts fail to meet basic standards of scientific rigour, resulting in rejection without the need for external evaluation—a pattern that colleagues at other journals have also observed. Prompted by these persistent concerns, in late 2023, our Editorial Board took the decision to raise the standard requirements for MR submissions. Throughout the past year, we have implemented stricter guidelines and had fewer MR submissions externally evaluated. Here, we explain the rationale behind these updates, highlight the most frequent pitfalls we encounter, and offers advice for conducting high-quality MR studies that we hope will be equally useful at other journals.