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Objective

To examine the role of hypertension, hyperglycemia, and dyslipidemia in potentially accounting for obesity-related brain vulnerability in the form of altered cerebral neurochemistry.

Design and Methods

Sixty-four adults, ages 40-60 years, underwent a health screen and proton magnetic resonance spectroscopy (1H MRS) of occipitoparietal gray matter to measure N-acetyl aspartate (NAA), choline (Cho), myo-inositol (mI), and glutamate (Glu) relative to creatine (Cr). The causal steps approach and nonparametric bootstrapping were utilized to assess if fasting glucose, mean arterial pressure or peripheral lipid/lipoprotein levels mediate the relationship between body mass index (BMI) and cerebral neurochemistry.

Results

Higher BMI was significantly related to higher mI/Cr, independent of age and sex. BMI was also significantly related to two of the proposed mediators, triglyceride, and HDL-cholesterol, which were also independently related to increased mI/Cr. Finally, the relationship between BMI and mI/Cr was significantly attenuated after inclusion of triglyceride and HDL-cholesterol into the model, one at a time, indicating statistical mediation.

Conclusions

Higher triglyceride and lower HDL levels statistically account for the association between BMI and myo-inositol, pointing toward a potentially critical role for dyslipidemia in the development of cerebral neurochemical alterations in obesity.