Selection bias when inferring the effect direction in Mendelian randomization

Affiliations

• ¹ PRecisiOn Medicine Translational Research (PROMoTeR) Center, Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston, Massachusetts, USA.
• ² Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA.
• ³ Department of Epidemiology, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA.
• ⁴ Department of Applied Mathematics, Computer Science and Statistics, Ghent University, Ghent, Belgium.
• ⁵ Department of Medical Statistics, London School of Hygiene and Tropical Medicine, London, UK.