The Association between Serum Neutrophil Gelatinase-Associated Lipocalin and Depression in Patients with Type 2 Diabetes Mellitus.

Background: Patients wtih type 2 diabetes mellitus (DM) have an increased risk of depressive symptoms. Whether serum neutrophil gelatinase-associated lipocalin (NGAL) is associated with depressive symptoms in old patients with type 2 DM is still uncertain.

Objective: We aim to investigate whether serum NGAL levels were associated with elevated risk of depressive symptoms in patients with type 2 DM in an old population.

Methods: Blood samples from 1012 hospitalized patients were measured for serum NGAL within the first 24 hours after admission. The Center for Epidemiological Studies Depression (CES-D) scale was performed to calculate depressive score. Cox analyses were used to examine the prognostic value of serum NGAL on detecting depressive symptoms during a median period of 5 years (range = 0.3-6.2 years).

Results: 136 (36.6)% of all subjects have depressive symptoms during the follow-up period. Linear analysis showed that serum NGAL levels at baseline were associated with CES-D score after adjusting for clinically relevant variables in type 2 DM patients (Sβ = 0.118, 95% CI 0.106-0.171, P < .001) but not in non-DM patients (Sβ = 0.025, 95% CI, -0.047-0.083; = .205). Cox analysis revealed that serum NGAL did have an independent prognostic value on predicting depressive symptoms (HR = 2.247, 95% CI 1.415-3.811, -trend<0.001, Model 2) in type 2 DM patients but not in non-DM patients (HR = 1.811, 95% CI 1.209-3.292, -trend = 0.189, Model 2) during follow-up period.

Conclusions: We found the first evidence that serum NGAL were strongly associated with depressive symptoms in patients with type 2 DM but not in non-DM patients. Further studies are needed to prove the underlying mechanism for the impact of type 2 DM on the association.