title: The Prevalence of 25-hydroxyvitamin D Deficiency in Japanese Patients with Diabetic Nephropathy.
abstract: Objective The purpose of this study was to measure serum 25-hydroxyvitamin D [25(OH)D] levels in Japanese patients with diabetic nephropathy and determine the relationship between 25(OH)D concentrations and various factors. Methods The study subjects included 442 patients with type 2 diabetes. Their serum levels of creatinine, HbA1c, intact-parathyroid hormone, urinary albumin, 25(OH)D, and 1,25-dihydroxyvitamin D [1,25(OH)2D] were measured and their estimated glomerular filtration rate (eGFR) was determined. The patients were divided into four groups based on the risk for progression to chronic kidney disease (CKD): low, moderate, high, very high, based on their eGFR and their level of albuminuria. Results The median 25(OH)D level was 14.6 ng/mL; 11% of the patients had 25(OH)D deficiency (<10 ng/mL), and 2% of patients had active vitamin D deficiency, as defined by a 1,25(OH)2D level of <22 pg/mL. The serum 25(OH)D level was correlated with the serum 1,25(OH)2D level in patients with a very high risk for CKD, but not in those with a moderate or high risk for CKD. Conclusion Although the vitamin D levels of the Japanese patients with diabetic nephropathy and CKD were low, the prevalence of vitamin D deficiency, as defined by the 1,25(OH)2D level, was low. Albuminuria, younger age, and female gender were associated with a low 25(OH)D level. The serum level of 25(OH)D should be monitored to assess the vitamin D status of patients with nephropathy and CKD.
authors.affiliation: Division of Nephrology, Endocrinology and Metabolism, Department of Internal Medicine, Tokai University School of Medicine, Japan.
authors.forename: Masumi
authors.initials: M
authors.lastname: Kondo
authors.forename: Masao
authors.initials: M
authors.lastname: Toyoda
authors.forename: Han
authors.initials: H
authors.lastname: Miyatake
authors.forename: Eitaro
authors.initials: E
authors.lastname: Tanaka
authors.forename: Masahiro
authors.initials: M
authors.lastname: Koizumi
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Komaba
authors.forename: Moritsugu
authors.initials: M
authors.lastname: Kimura
authors.forename: Tomoya
authors.initials: T
authors.lastname: Umezono
authors.forename: Masafumi
authors.initials: M
authors.lastname: Fukagawa
mesh_terms: D000367:Age Factors; D000368:Aged; D000419:Albuminuria / Q000378:metabolism; D002112:Calcifediol; D003404:Creatinine / Q000097:blood; D003924:Diabetes Mellitus, Type 2 / Q000150:complications*; D003928:Diabetic Nephropathies / Q000453:epidemiology*; D018450:Disease Progression; D005260:Female; D006442:Glycated Hemoglobin; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D010281:Parathyroid Hormone / Q000097:blood; D015995:Prevalence; D051436:Renal Insufficiency, Chronic / Q000453:epidemiology; D012307:Risk Factors; D012720:Severity of Illness Index; D012737:Sex Factors; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000453:epidemiology*
chemical_list: D002112:Calcifediol; D003404:Creatinine; D006442:Glycated Hemoglobin; D010281:Parathyroid Hormone; D014807:Vitamin D; C104450:25-hydroxyvitamin D