IGF1 and sleep apnea syndrome: However, these studies failed to demonstrate a correlation between GH and IGF-I levels and RNLF thickness, thus leading to the conclusion that RNLF thinning might been ascribed to the macroadenoma-induced optic chiasm compression, as well as to arterial hypertension, sleep apnea and/or papilloedema rather than to the hormonal status per se [15, 17, 18].