Cross-sectional study examining the association between metabolic syndrome and cognitive function among the oldest old

Objectives: Metabolic syndrome (MetS), which includes obesity, hypertension, dyslipidemia, and insulin resistance, has been shown to predispose people to cognitive impairment and dementia. In this study, we aimed to examine the relationship between MetS and cognitive impairment among the oldest-old people using a cohort of Chinese individuals aged 90 to 108 years.

Methods: The Project of Longevity and Aging in Dujiangyan is a population-based study of 870 people aged 90 years and older. Cognitive function was evaluated using Mini-Mental State Examination, and venous blood samples were collected after an overnight fast to measure the biochemistry indicators.

Results: Among the 767 participants for this analysis, the mean age was 93.6 ± 3.3 years (range 90-108 years), 516 (67.3%) were women, and 53 were centenarians. The mean Mini-Mental State Examination score was 15.0 ± 5.9. The total prevalence rate of MetS was 9.3%. After adjusting for age, sex, educational levels, smoking, drinking, and exercise, MetS was associated with a lower odds ratio (OR) of having cognitive impairment (OR = 0.443, 95% CI, 0.255-0.769) among the total population. Among men, a high triglyceride level was also associated with a lower OR of having cognitive impairment (OR = 0.434, 95% CI, 0.191-0.989).

Conclusion: MetS may be associated with better cognitive function among the oldest old. Among male nonagenarians and centenarians, high triglyceride level and systolic blood pressure, which are parts of MetS, are also associated with better cognitive function.