title: Impact of vitamin D on proteinuria, insulin resistance, and cardiovascular parameters in kidney transplant recipients.
abstract: Low vitamin D levels prevalent in patients with chronic kidney disease have been reported to be associated with proteinuria, insulin resistance, and cardiovascular disease. Kidney transplant recipients are also susceptible to low vitamin D levels but their clinical significance is uncertain. This study investigated the prevalence and association of vitamin D insufficiency with proteinuria, insulin resistance, and cardiovascular parameters among 95 living donor kidney transplant recipients. Levels of 25-hydroxyvitamin D [25(OH)D] were stratified into an insufficient group [25(OH)D≤30 ng/mL; n=19] versus a normal group [25(OH)D>30 ng/mL; n=76]. Proteinuria (urinary protein-creatinine [P/C]≥0.2 mg/mg), insulin resistance (homeostasis model assessment of insulin resistance [HOMA-IR]) and cardiovascular parameters were compared between groups. Twenty percent of subjects showed vitamin D insufficiency. Proteinuria was higher among the vitamin D insufficient than the normal group (47.4% vs 18.7%; P=.02). 25(OH)D levels inversely correlated with urinary P/C ratio and intact parathyroid hormone (I-PTH) levels (r=-.24, P=.02 and r=-.23, P=.02, respectively). No correlations were observed between 25(OH)D levels and HOMA-IR scores or cardiovascular parameters. On univariate analysis, proteinuria and i-PTH levels were independent predictors of vitamin D insufficiency (P<.01 and P=.03, respectively). Multivariate analysis demonstrated proteinuria to be a significant predictor of vitamin D insufficiency (odds ratio=4.526; P=.03). In conclusion, vitamin D insufficiency was common and significantly associated with proteinuria among kidney transplant recipients. Additional studies are needed to clarify the causal relationship of vitamin D insufficiency with proteinuria and to determine the role of vitamin D supplementation to attenuate the development of proteinuria.
authors.affiliation: Division of Nephrology, Department of Internal Medicine, Maryknoll General Hospital, Busan, Republic of Korea. egis70@naver.com
authors.forename: D R
authors.initials: DR
authors.lastname: Lee
authors.forename: J M
authors.initials: JM
authors.lastname: Kong
authors.forename: K I
authors.initials: KI
authors.lastname: Cho
authors.forename: L
authors.initials: L
authors.lastname: Chan
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood / Q000652:urine; D001916:Brachial Artery / Q000503:physiopathology; D002318:Cardiovascular Diseases / Q000175:diagnosis / Q000453:epidemiology* / Q000503:physiopathology; D002339:Carotid Arteries / Q000000981:diagnostic imaging; D016009:Chi-Square Distribution; D003404:Creatinine / Q000652:urine; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007333:Insulin Resistance; D016030:Kidney Transplantation / Q000009:adverse effects*; D019520:Living Donors; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D010281:Parathyroid Hormone / Q000097:blood; D015995:Prevalence; D011507:Proteinuria / Q000175:diagnosis / Q000453:epidemiology* / Q000652:urine; D056910:Republic of Korea / Q000453:epidemiology; D018570:Risk Assessment; D012307:Risk Factors; D018616:Ultrasonography, Doppler, Duplex; D014664:Vasodilation; D014807:Vitamin D / Q000031:analogs & derivatives / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology*; D055815:Young Adult
chemical_list: D015415:Biomarkers; C470125:PTH protein, human; D010281:Parathyroid Hormone; D014807:Vitamin D; C104450:25-hydroxyvitamin D; D003404:Creatinine