COB concentration <295.2 pmol/l (~400 ng/l) indicating the need for supplementation31 was common (24.5%, n = 34/139), as well as IGF-1 >746 ng/ml suggestive of hypersomatotropism (17.5%, n = 17/97).28 The frequency of known or suspected hyperthyroidism was 5.8% (n = 8/139). This evidence concerns the gene IGF1 and hyperthyroidism.