Changes in cerebral metabolites in type 2 diabetes mellitus: A meta-analysis of proton magnetic resonance spectroscopy

To investigate whether there were differences and consistent patterns that highlight and consolidate the metabolite changes in type 2 diabetes mellitus (T2DM), a meta-analysis of proton magnetic resonance spectroscopy (MRS) was conducted. PubMed, Web of Science, and Embase databases were searched up to August 2016 for collecting the relevant studies. After an inclusion and exclusion criteria, the data was extracted. The data was analyzed using Stata software v.12.0. The weight mean difference (MD) and 95% confidence interval (CI) were used to compare continuous variables. A total of 10 studies (with a total of 244 T2DM patients and 223 healthy controls) were included. N-Acetyl Aspartate (NAA)/creatine (Cr) levels were decreased in the frontal lobe (MD = −0.20, 95%CI = −0.33 to −0.06, P = 0.005) and lenticular nucleus (MD = −0.14, 95%CI = −0.22 to −0.06, P = 0.001); choline (Cho)/Cr levels were increased in the lenticular nucleus (MD = 0.15, 95%CI = 0.02-0.28, P = 0.025); myo-inositol (MI)/Cr levels were increased in the in the occipital lobe (MD = 0.11, 95%CI = 0.02-0.19, P = 0.017) and parietal lobe (MD = 0.16, 95%CI = 0.05-0.28, P = 0.006); MI levels were increased in the frontal white matter (MD = 0.52, 95%CI = 0.14-0.90, P = 0.008). The results of our meta-analysis indicated that metabolite levels were altered in different regions of brain, which may be shown with MRS and caused clinical symptoms in T2DM further.