Differential Effects of Body Mass Index on Domain-Specific Cognitive Outcomes After Stroke

Background: We aimed to investigate the association between body mass index (BMI) and domain-specific cognitive functions in post-ischemic stroke survivors. Methods: A total of 335 ischemic stroke patients were included in the study after completion of the Korean-Mini-Mental Status Examination (K-MMSE) and the K-VCIHS neuropsychological protocol at 3 months after stroke. Frontal lobe functions were analyzed using semantic/phonic fluency, processing speed, and mental set shifting. Our study participants were categorized into four groups according to BMI quartiles Results: The K-MMSE scores at 3 months differed significantly between the groups after adjustment for covariates with univariate p-value less than 0.1 (p = 0.003). Global cognitive function in stroke survivors in the Q1 BMI group was significantly lower than those in Q2 and Q4 BMI groups (K-MMSE scores, Q1: 22.9 ± 6.7 vs. Q2: 25.2 ± 5.2 and Q4: 25.1 ± 4.3). Controlled oral word association test findings indicated that phonemic and semantic word fluency was lower in Q4 BMI group participants than in Q2 BMI group participants (p = 0.012, and p=0.012 respectively). Conclusions: BMI might differentially affect cognitive domains after ischemic stroke. Although being underweight may negatively affect global cognition post-stroke, obesity could induce frontal lobe dysfunctions, specifically phonemic and semantic word fluency.