Association Between Serum Vitamin D and Albuminuria in Type 2 Diabetes Independent of Inflammatory Markers and Renal Function

Abstract

Introduction: To explore the relationship between serum high-sensitivity C-reactive protein (hs-CRP), tissue necrosis factor-alpha (TNF-alpha) and 25-Hydroxyvitamin D (25(OH) vitamin D) with albuminuria in patients with type 2 diabetes mellitus (T2D). Methods: This was a cross-sectional study of 86 T2D patients divided into categories of with and without albuminuria based on the urine albumin-to-creatinine ratio (UACR). A 25(OH) vitamin D concentration <= 15 ng/mL was defined as vitamin D deficiency, within 15-30 ng/mL as vitamin D insufficiency, and > 30 ng/mL as serum 25(OH) vitamin D sufficiency. A hs-CRP level <= 2.5 mg/L was considered low, whereas a hs-CRP level > 2.5 mg/L was considered high. TNF-alpha was classified as low or high with an 8.2 pg/mL cutoff level based on receiver operating characteristic (ROC) curve analysis. P values < 0.05 were considered to be significantly associated with albuminuria. Results: Vitamin D deficiency was significantly more commonly observed among T2D patients with albuminuria than those without albuminuria (adjusted OR = 7.34, 95 CI = 2.3-23.6, p = 0.001). Higher serum TNF-alpha levels (TNF-alpha > 8.2 pg/mL) were more frequently associated with the presence of albuminuria in T2D patients (adjusted OR = 6.77, 95 CI = 1.61-28.4; p = 0.009). Similarly, elevated serum hs-CRP levels (hs-CRP > 2.5 mg/L) were more commonly found among patients with T2D and albuminuria than in those without (adjusted OR = 4.7, 95 CI = 1.4-15.8; p = 0.012). Conclusions: Vitamin D deficiency is a significant correlate of albuminuria in T2D patients, independent of glomerular filtration rate (GFR) and basic inflammatory markers including hs-CRP and TNF-alpha. Moreover, serum hs-CRP > 2.5 mg/L and TNF-alpha > 8.2 pg/mL were each individually associated with a significantly increased likelihood of albuminuria in T2D patients.