Response by Bano et al to Letter Regarding Article, “Thyroid Function and the Risk of Atherosclerotic Cardiovascular Morbidity and Mortality: The Rotterdam Study”

We appreciate the comments by Drs Zhao and Schooling on our recent publication.1 In this study, we showed that higher circulating free thyroxine levels are associated with an increased risk of atherosclerosis throughout its full spectrum. Zhao and Schooling2 argue that our observed associations are not supported by an MR study (Mendelian Randomization), which found no evidence of an association between thyroid function and ischemic heart disease. The following considerations need to be taken into account with regard to this study. First, the MR study focused on coronary artery disease. However, there are no MR studies, to our knowledge, on thyroid function and atherosclerotic cardiovascular disease. Second, the MR approach assumes that genetic variants determine the exposure. Still, only a limited number of genetic variants for …