Evaluation of Neutrophil Gelatinase-associated Lipocalin in Normoalbuminuric Normotensive Type 1 Diabetic Adolescents

Aims: The aims of this study were to determine neutrophil gelatinase-associated lipocalin (NGAL) levels in normoalbuminuric and normotensive adolescents with type 1 diabetes and to assess the relationship between NGAL and clinical and laboratory variables.

Methods: Forty-six adolescents with type 1 diabetes [male/ female (M/F) ratio, 24/22; median age, 14.5 years; range, 12.2-16 years; diabetes duration, 4.8 years; range, 2.6-6.7 years; hemoglobin A1c (HbA1c), 7.9%; range, 7.2%-9.2%] and 21 healthy controls (M/F, 7/14; median age, 14.8 years; range, 13.6-15.5 years) were compared regarding clinical, laboratory, and ambulatory blood pressure monitoring variables.

Results: Median blood and urine glucose, HbA1c, urine NGAL/creatinine ratio [13.2 (range, 8.3-43.1) vs. 4.8 (range, 2.9-20.2), p = 0.015], and daytime systolic and diastolic blood pressure (BP) standard deviation score and BP loads were found higher in diabetic adolescents. Urine NGAL levels were found to be correlated with albumin/creatinine ratio (r = 0.452, p = 0.002), whereas plasma NGAL levels were correlated with nighttime systolic BP load (r = 0.309, p = 0.037). Patients with high-normal albuminuria (n=6) had higher urine NGAL levels [48.7 ng/mL (range, 27.9-149.1 ng/mL) vs. 14.3 ng/mL (range, 3.5-41 ng/mL), p = 0.014] and urine NGAL/creatinine ratio [39.3 ng/mg (range, 21.1-126.3 ng/mg) vs. 11.8 ng/mg (range, 6.3-40.9 ng/mg), p = 0.03] compared with those of controls and higher urine NGAL levels compared with that of diabetic adolescents with low-normal albuminuria [n=40, 11.2 ng/mL (range, 6-23.4 ng/mL), p = 0.004].

Conclusions: Normoalbuminuric and normotensive adolescents with type 1 diabetes have elevated urinary NGAL values, which might indicate kidney injury.