The Relationship between Body Mass Index and Cognitive Function in Healthy Young Adults

Abstract Background: Young adulthood is a key developmental stage of life. Malnutrition at this stage can have a detrimental effect on cognitive functioning. Underweight and obesity can both adversely affect neurocognitive development. The association between body mass index (BMI) and cognitive performance is debatable. Objective: This study investigates the relationship between BMI and cognitive function in young adult age students. Methodology: This cross-sectional study was done on 200 medical undergraduate students aged between 18-25 years. Different cognitive domains were assessed through Trail making test A (TMT-A), Trail making test B (TMT-B), Animal name test (ANT), Design fluency test (DFT), Digit span forward and Digit span reverse test. The test score of different BMI categories and also the association between BMI and test score were analyzed. Result: For the total population, with an increase in BMI, better cognitive performance was observed in the TMT-B (p=0.047r=-0.140), ANT (p=0.036, r=+0.146) and novel output score of DFT (p=0.019, r=+0.164). Among female participants, significant negative correlation was found between TMT-A (p=0.007, r=-0.267), TMT-B (p=0.017, r=-0.237) and positive correlation between ANT (p=0.0008, r=+0.328), novel output score of DFT (p=0.032, r=+0.214). A statistically significant difference was found in the ANT test performance between the four groups of BMI (P = 0.009). Among the female participants significant differences were observed between the four BMI categories for TMT-A (P= 0.014), TMT-B (P=0.001) and ANT test (P=0.0002). Conclusion: Lower BMI is associated with a higher risk of cognitive impairment in young adults. The negative impact of lower BMI on cognitive performance is more prominent among females.