The relationship between metabolically healthy obesity and cognitive function: a systematic review of observational studies

Matina Kouvari, Nathan D'Cunha, Domenico Sergi, Manja Zec, Nenad Naumovski

Research output: Contribution to conference (non-published works)Abstractpeer-review


Metabolically healthy obesity (MHO) is an established model to investigate the mechanisms linking obesity and its complications, including cognitive impairment, in the absence of metabolic aberrations. The aim of this systematic review was to evaluate whether MHO represents a risk factor for cognitive decline, with a particular focus on dementia and Alzheimer’s disease (AD) onset.

Following PRISMA guidelines, a systematic literature search was performed using PubMed and Scopus.

Only two studies (n=365,131 participants) met the eligibility criteria. The first study used data from National Health Insurance System (NHIS) of Korea, while the second used data from Alzheimer’s Disease Neuroimaging Initiative (ADNI) cohort from USA. Study heterogeneity was mostly attributed to: a. study design (retrospective vs. prospective), b. target population (middle-aged vs. older adults) and c. categorization of combined weight and metabolic status (normo-weight grouped with overweight vs. obese grouped with overweight), respectively. While AD was assessed in both studies, overall dementia was examined only in NHIS study. Metabolic status was classified according to ≤1 ATPIII criteria (excluding waist circumference). The NHIS study revealed that MHO subjects had the lowest odds of developing dementia compared to normo-weight (irrespective of their metabolic status) and metabolically unhealthy obese. Multivariate analysis revealed that MHO resulted in 15% and 13% lower likelihood for dementia and AD, respectively, compared with normo-weight healthy subjects (All p’s<0.05). In ADNI study, compared with healthy overweight/obese, healthy normo-weight, unhealthy normo-weight and unhealthy overweight/obese, had 36%, 72% and 34% higher risk for AD (All p’s<0.05).

The combined analysis suggests that individuals with excess weight yet metabolically healthy have lower risk of dementia and AD compared to unhealthy participants or even healthy participants with normal weight. Nevertheless, these findings should be interpreted with caution, as studies with longer follow-up and integrated assessments of metabolic and cognitive status are needed.
Original languageEnglish
Number of pages1
Publication statusPublished - 2021
EventThe 19th International Symposium on Atherosclerosis: Toward Healthy Aging though Atheroclerosis Science - Kyoto, Kyoto, Japan
Duration: 24 Oct 202127 Oct 2021


ConferenceThe 19th International Symposium on Atherosclerosis
Abbreviated titleISA2021
Internet address


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