Relationship between advanced glycated end products and maternal cognition in gestational diabetes: a case control study.

Objective: Gestational diabetes (GDM) is a form of glucose intolerance which manifests during pregnancy. There is lack of literature regarding the study of cognitive functions in GDM. Recent evidences suggests an increase in accumulation of serum Advanced glycated end products (AGE'S) during GDM. Accumulation of AGE's in brain can induce changes in permeability of blood brain barrier and creates oxidative stress and inflammation that can alter cognitive functions. In this study we hypothesize that diagnosis of GDM in pregnancy is related to lower cognitive scores which is correlated to increased serum AGE's level.

Method: This was a cross sectional case control study which recruited 60 participants in total consisting of two groups with 30 participants in each - diagnosed cases of GDM and healthy pregnant controls. Subjects were recruited from OPD of Obstetrics & Gynecology department in a tertiary care hospital in South India at gestational age of 32-36 weeks. On the first appointment, biochemical parameters of Fasting plasma glucose (FPG) & HbA1C was measured in both groups. Serum was obtained for testing levels of N Carboxy methyl lysine (N-CML) (a form of AGE). On second appointment, pen and paper neurocognitive tests including Montreal cognitive tests (MOCA) and Trail making test (TMT A & B) was presented. Event related potentials (ERP's) are time locked EEG wave signals produced in response to a sensory, motor or cognitive event. P300 is an "endogenous" ERP produced by cognitive processing in response to a stimuli presented to subject. P300 wave Latency and amplitude was recorded in both the groups as an objective marker of cognitive processing. Above mentioned biochemical and neurocognitive parameters were compared between both the groups and correlation analysis between serum AGE levels and neurocognitive parameters was performed using SPSS software.

Results: Biochemical parameters of HbAIC & N-CML(A form of AGE) levels were increased in GDM group (HbA1C 6.01±0.30 and N CML 236.25 ± 68.9) vs Control group (HbA1C 4.11 ± 0.68 and NCML 198.42 ± 44.2). Scores in MOCA were significantly lower in GDM (28 (27-29)) group as compared to controls (24 (23-25)). GDM subjects took significantly greater time to perform TMT A (24.59 ± 2.60 s) test than controls (29.7 ± 1.72 s). Significant changes were not found in P300 Latency & amplitude in GDM group. Decreased MOCA scores and increased duration of TMT A attempt were correlated with increased serum AGE concentration in GDM group.

Conclusions: Our study indicates the vulnerability of women suffering from GDM to cognitive impairment during pregnancy. Lower scores in cognitive tests were correlated to AGE accumulation in GDM women.