FGF23 and chronic kidney disease: Though our findings are in line with those of the Chronic Renal Insufficiency Study [44], in which in stage 2–4 CKD patients no significant association was observed between FGF23 and dietary phosphorus intake, in the Health Professionals Follow-up Study each 500 mg increase in dietary phosphorus intake was associated with 3.4 RU/mL higher serum FGF23 levels[45].