Contribution of Metabolic Syndrome Components to Cognition in Older Persons

Abstract

OBJECTIVE Recent evidence suggests that the metabolic syndrome (MetS) and inflammation affect cognitive decline in old age, and that they reinforce each other. It is unknown what the role of the individual components of MetS on cognition is.

RESEARCH DESIGN AND METHODS The sample consisted of 1,183 participants of the Longitudinal Aging Study Amsterdam (LASA), aged 65 to 88 years. MetS (US National Cholesterol Education Program definition) and its individual components, and the inflammatory markers C-reactive protein (CRP) and α1-antichymotrypsin (ACT) were assessed. Cognitive assessments included general cognition (MMSE), memory (verbal learning test), fluid intelligence (Raven's matrices), and information processing speed (coding task).

RESULTS 36.3% of the sample had MetS. MetS was significantly associated with all cognitive measures (p<0.05). Of the individual components, hyperglycemia was most strongly and significantly associated with cognitive function (multivariate adjusted models; B's, indicating differences in scores between both groups, ranging from -0.38 to --1.21). There was a significant interaction between MetS and inflammation on cognition (p<0.01 to 0.09). MetS was negatively associated with cognition in subjects with high inflammation (highest tertile on both CRP and ACT; B's range from -0.86 to -1.94, p<0.05), whereas an association was absent in subjects with low inflammation (B's range -0.10 to -0.70).

CONCLUSIONS Subjects with MetS showed poorer cognitive performance than subjects without MetS, especially in those with high levels of inflammation. Hyperglycemia was the main contributor of the association of MetS with cognition.