Plasma free thyroxine in the upper quartile is associated with an increased incidence of major cardiovascular events in older men that do not have thyroid dysfunction according to conventional criteria. Golledge, J., Hankey, G.J., Almeida, O.P., Flicker, L., Norman, P.E. and Yeap, B.B., 2018.International journal of cardiology, 254, pp.316-321.