Metabolic syndrome and cognitive function in healthy middle-aged and older adults without diabetes

Few studies have addressed whether the metabolic syndrome (MetS) and its individual components are associated with cognitive function in middle-aged and older populations, as well as whether specific areas of cognition are more affected than others. We examined the cross-sectional association between MetS and six areas of cognitive function in healthy cognitively intact adults without diabetes (n = 853, mean age 61 years) randomized in two intervention trials.

The National Cholesterol Education Program (NCEP) criteria were used to identify subjects with MetS. Cognitive function was assessed with a neuropsychological battery. A principal components analysis was used to extract five uncorrelated factors interpreted to represent five areas of cognition, and a measure of global cognition was calculated.

MetS was weakly but non-significantly associated with lower verbal learning (beta = -.14 [SE(beta) = 0.09], p = .15). As the number of MetS criteria increased, scores on global cognition (p trend = .01), verbal learning (p trend = .06) and semantic memory (p trend = .04) decreased. Hypertension was the only MetS risk factor that was independently correlated with lower verbal learning (beta = -.17 [SE(beta) = 0.08], p = .04), semantic memory (beta = -.26 [SE(beta) = 0.08], p = .001) and global cognition (beta = -.15 [SE(beta) = 0.07], p = .04).

This study adds to the evidence of an association between MetS and lower cognitive function among healthy middle-aged and older adults without CVD and diabetes, as well as confirms the correlation between hypertension and lower cognition.