Impaired vitamin D metabolism in CKD.

Vitamin D metabolism consists of both production and catabolism, which are enzymatically driven and highly regulated. Renal vitamin D metabolism requires filtration and tubular reabsorption of 25-hydroxyvitamin D and is regulated by parathyroid hormone, fibroblast growth factor-23, and 1,25-dihydroxyvitamin D. In chronic kidney disease, renal production of 1,25-dihydroxyvitamin D from 25-hydroxyvitamin D is reduced.

Parathyroid hormone and arterial dysfunction in the multi-ethnic study of atherosclerosis.

Objective: High circulating concentrations of parathyroid hormone (PTH) have been associated with increased risks of hypertension, left ventricular hypertrophy, congestive heart failure and cardiovascular mortality. Impaired arterial function is a potential mechanism for these associations. We tested whether serum PTH concentration is associated with measures of arterial function.

The serum 24,25-dihydroxyvitamin D concentration, a marker of vitamin D catabolism, is reduced in chronic kidney disease.

Chronic kidney disease is characterized, in part, as a state of decreased production of 1,25-dihydroxyvitamin D (1,25(OH)(2)D); however, this paradigm overlooks the role of vitamin D catabolism. We developed a mass spectrometric assay to quantify serum concentration of 24,25-dihydroxyvitamin D (24,25(OH)(2)D), the first metabolic product of 25-hydroxyvitamin D (25(OH)D) by CYP24A1, and determined its clinical correlates and associated outcomes among 278 participants with chronic kidney disease in the Seattle Kidney Study. For eGFRs of 60 or more, 45-59, 30-44, 15-29, and under 15 ml/min per 1.

The effect of combined calcium and cholecalciferol supplementation on bone mineral density in elderly women with moderate chronic kidney disease.

Aims: To examine the effect of combined calcium and vitamin D3 supplementation on bone mineral density (BMD) inpatients with chronic kidney disease (CKD).

Methods: We performed a post-hoc analysis of the DECALYOS II, a 2-year randomized, double-blind, placebo-controlled study of 610 women randomized to: calcium-vitamin D3 fixed combination, calcium plus vitamin D3 separate combination, or placebo. Both active treatment groups received the same daily amount of calcium (1,200 mg) and vitamin D3 (800 IU).

Relationship of serum bilirubin concentrations to kidney function and albuminuria in the United States adult population. Findings from the National Health and Nutrition Examination Survey 2001-2006.

Background: The association of serum bilirubin concentrations with kidney function and albuminuria has not been established in the US general population.

Methods: We performed a cross-sectional analysis of data from the National Health and Nutrition Examination Survey (NHANES) 2001-2006 and examined the associations of serum total bilirubin concentrations with estimated glomerular filtration rate (eGFR) and albuminuria in a nationally representative sample of 13,184 adults aged 20 years or older. eGFR was estimated using the abbreviated Modification of Diet in Renal Disease equation.