25-vitamin D, 1,25-vitamin D, parathyroid hormone, fibroblast growth factor-23 and cognitive function in men with advanced CKD: a veteran population.

Cognitive impairment is common in advanced chronic kidney disease (CKD), but little is known about its relation with abnormalities in mineral metabolism. The longitudinal association between plasma 25-hydroxyvitamin D (25(OH)D), 1,25-dihydroxyvitamin D (1,25(OH)D), intact parathyroid hormone (iPTH), and fibroblast growth factor-23 (FGF-23) levels and cognitive function was assessed in 605 patients (67 ± 12 years) with advanced CKD not requiring dialysis (n = 247) or end-stage renal disease (ESRD; n = 358) who participated in the Homocysteine Study Cognitive Function Substudy (HOSTCOG)). Cognitive function was assessed using the Telephone Interview for Cognitive Status-modified (TICSm; mean follow-up 3.