Managing the exponential growth of Mendelian randomization studies

There has been a rapid growth in studies that simply use summary genome-wide association studies (GWAS)data to estimate the causal effect of X on Y. With the increasing risk of genetic confounding, these studies offer little more than a conventional observational study and are a low priority for publication unless they also use additional methods. This could include exploring complex exposures and/or outcomes (including testing for possible mediation via multivariable MR), incorporating negative controls and/or evidence from other study designs such as natural experiments and advancing plausible biological mechanisms.