Whether obesity is a cause of type 2 diabetes mellitus and coronary heart disease or a shared risk factor has been an enduring subject of debate. Lyall and colleagues have used Mendelian randomization to conclude that there is a causal relationship between obesity and cardiometabolic disease. However, the analyses fail key inherent assumptions. The article does not negate a large body of data indicating that insulin resistance is the primary mechanism driving the progression of cardiometabolic disease.
Refers to Lyall, D. M, et al. Association of body mass index with cardiometabolic disease in the UK Biobank: a Mendelian randomization study. JAMA Cardiol.http://dx.doi.org/10.1001/jamacardio.2016.5804 (2017)