Effect of obesity on cognitive function: a cross-sectional study
Keywords:Body mass index, Reaction time, Jolly-fat hypothesis
Background: Obesity is the leading cause of many health problems. It mostly affects the brain by cerebrovascular events, but since it is a chronic low-grade inflammatory state, inflammatory cytokines in blood alter neuronal function. The jolly-fat hypothesis says that obese people have better cognition as they have more fat storage which is required to make neurotransmitters. Many studies have been done to support each of the above hypotheses but most are done in the paediatric or geriatric populations which can have other confounding factors. Obesity can be easily treated with proper dietary interventions, exercise, pharmaceutical therapies, or surgical interventions. Thus, it was worth exploring as simple lifestyle changes might lower the incidence of cognitive disabilities.
Methods: This study was done on undergraduate medical students with a sample size of 120 (60 male and 60 female). Their body mass index was calculated after taking body weight and height. The cognition of subjects was studied using the Washington click reaction time test. This was correlated with body mass index using a t test to find a p value with a level of significance of 0.05.
Results: High body mass index is associated with poor cognition as the p<0.05 (0.025006). There was no role of gender on body mass index or cognitive functions.
Conclusions: Obesity does affect the cognitive function in healthy adult populations with no comorbidities irrespective of the gender of the individual. More prospective studies with a more sensitive battery of tests can be done to further understand this.
Melo HM, Santos LE, Ferreira ST. Diet-Derived Fatty Acids, Brain Inflammation, and Mental Health. Front Neurosci. 2019;13:265.
Wainwright PE. Dietary essential fatty acids and brain function: a developmental perspective on mechanisms. Proc Nutr Soc. 2002;61(1):61-9.
Chang EH, Chavan SS, Pavlov VA. Cholinergic Control of Inflammation, Metabolic Dysfunction, and Cognitive Impairment in Obesity-Associated Disorders: Mechanisms and Novel Therapeutic Opportunities. Front Neurosci. 2019;13:263.
McIntyre RS, Rong C, Mansur RB, Brietzke E. Does obesity and diabetes mellitus metastasize to the brain? "Metaboptosis" and implications for drug discovery and development. CNS Spectr. 2019;24(5):467-9.
Chen PY, Liu SK, Chen CL, Wu CS. Long-term statin use and dementia risk in Taiwan. J Geriatr Psychiatry Neurol. 2014;27(3):165-71.
Mestre ZL, Bischoff-Grethe A, Eichen DM, Wierenga CE, Strong D, Boutelle KN. Hippocampal atrophy and altered brain responses to pleasant tastes among obese compared with healthy weight children. Int J Obes (Lond). 2017;41(10):1496-1502.
Mehra A, Suri V, Kumari S, Avasthi A, Grover S. Association of mild cognitive impairment and metabolic syndrome in patients with hypertension. Asian Journal of Psychiatry. 2020;53:102185.
Waldstein SR, Katzel LI. Interactive relations of central versus total obesity and blood pressure to cognitive function. Int J Obes (Lond). 2006;30(1):201-7
Zhang L, Li JL, Zhang LL, Guo LL, Li H, Yan W, Li D. Relationship between adiposity parameters and cognition: the "fat and jolly" hypothesis in middle-aged and elderly people in China. Medicine (Baltimore). 2019;98(10):e14747.
Han C, Jo SA, Seo JA, Kim BG, Kim NH, Jo I, Park MH, Park KW. Adiposity parameters and cognitive function in the elderly: application of "Jolly Fat" hypothesis to cognition. Arch Gerontol Geriatr. 2009 Sep;49(2): e133-8.
Clark LR, Koscik RL, Allison SL, Berman SE, Norton D, Carlsson CM, Betthauser TJ, Bendlin BB, Christian BT, Chin NA, Asthana S, Johnson SC. Hypertension and obesity moderate the relationship between β-amyloid and cognitive decline in midlife. Alzheimers Dement. 2019;15(3):418-28.
Ganguli M, Beer JC, Zmuda JM, Ryan CM, Sullivan KJ, Chang CCH et al. Aging, Diabetes, Obesity, and Cognitive Decline: A Population-Based Study. J Am Geriatr Soc. 2020;68:991-8.
Faculty of Washington University. Online Reaction Time Test, 2002 Available at: https://faculty.washington.edu/chudler/java/redgreen.html. Accessed on 20 December 2021.
Kumar PA, Omprakash A, Kuppusamy M, Ramaswamy P. How does cognitive function measured by the reaction time and critical flicker fusion frequency correlate with the academic performance of students? BMC Med Educ. 2020;20(1):507.
Shand AG, Wilding JPH, Nutritional factors in disease. In: Ralston S, Penman I, Strachan M, Hobson R. Davidson's Principles and Practice of Medicine E-Book. 23rd ed. Philadelphia: Elsevier. 2018:700.
Ward MA, Carlsson CM, Trivedi MA, Sager MA, Johnson SC. The effect of body mass index on global brain volume in middle-aged adults: a cross-sectional study. BMC Neurol. 2005;5:23.
Hassing LB, Dahl AK, Pedersen NL, Johansson B. Overweight in midlife is related to lower cognitive function 30 years later: a prospective study with longitudinal assessments. Dement Geriatr Cogn Disord. 2010;29(6):543-52.
Hou Q, Guan Y, Yu W, Liu X, Wu L, Xiao M et al. Associations between obesity and cognitive impairment in the Chinese elderly: an observational study. Clin Interv Aging. 2019;14:367-73.
Kuo HK, Jones RN, Milberg WP, Tennstedt S, Talbot L, Morris JN et al. Cognitive function in normal-weight, overweight, and obese older adults: an analysis of the Advanced Cognitive Training for Independent and Vital Elderly cohort. J Am Geriatr Soc. 2006;54(1):97-103.
Fernando HJ, Cohen RA, Gullett JM, Friedman J, Ayzengart A, Porges E et al. Neurocognitive Deficits in a Cohort With Class 2 and Class 3 Obesity: Contributions of Type 2 Diabetes and Other Comorbidities. Obesity. 2019;27:1099-106.
Elias MF, Elias PK, Sullivan LM, Wolf PA, D'Agostino RB. Obesity, diabetes and cognitive deficit: The Framingham Heart Study. Neurobiol Aging. 2005;26(1):11-6.
Schmeidler J, Mastrogiacomo CN, Beeri MS, Rosendorff C, Silverman JM. Distinct age-related associations for body mass index and cognition in cognitively healthy very old veterans. Int Psychogeriatr. 2019;31(6):895-9.
Jagust W, Harvey D, Mungas D, Haan M. Central obesity and the aging brain. Arch Neurol. 2005;62(10):1545-8.