PTH and chronic kidney disease: In a cross-sectional analysis of 14,289 unselected patients with CKD, in CKD stages G3–G5, progressively higher 25(OH)D pentiles contained progressively lower mean PTH levels with no evidence of a decreasing effect of 25(OH)D to lower PTH until 25(OH)D levels of 42–48 ng/mL (105–120 nmol/L) [77].