Metabolic Syndrome and High-Obesity-Related Indices Are Associated with Poor Cognitive Function in a Large Taiwanese Population Study Older than 60 Years

Metabolic syndrome (MetS) is prevalent in Taiwan; however, the association between MetS and cognitive function is unclear. The aim of this study was to explore the associations between MetS, its components, and obesity-related indices with cognitive function in a large Taiwanese cohort. We enrolled a total of 28,486 participants who completed the Mini-Mental State Examination (MMSE) questionnaire, which was used to evaluate cognitive function. MetS was defined according to the NCEP-ATP III guidelines and modified criteria for Asians. Ten obesity-related indices were also evaluated: body mass index (BMI), abdominal volume index (AVI), body adiposity index (BAI), waist–hip ratio (WHR), a body shape index (ABSI), lipid accumulation product, waist-to-height ratio (WHtR), conicity index (CI), body roundness index (BRI), and triglyceride glucose index. The prevalence of MetS and its components (except for hypertriglyceridemia) and the number of MetS components increased while the cognitive impairment worsened (from MMSE ≥ 24, 18–23 to 0–17). In addition, increases in all obesity-related index values were associated with a decline in cognitive function (from MMSE ≥ 24, 18–23 to 0–17, ANOVA p < 0.001). Multivariable analysis showed that MetS (p = 0.002), abdominal obesity (p < 0.001), low high-density lipoprotein cholesterol (p = 0.004), and hyperglycemia (p = 0.012) were significantly associated with a low MMSE score. Further, participants with high BMI (p = 0.001), WHR (p < 0.001), WHtR (p < 0.001), BRI (p < 0.001), CI (p < 0.001), BAI (p < 0.001), AVI (p < 0.001), and ABSI (p < 0.001) values were significantly associated with a low MMSE score. Our results show that MetS and its components (except for hypertriglyceridemia and high blood pressure) may lead to cognitive impairment, and that high values of obesity-related indices were associated with poor cognitive function.