Association of cognitive performance with the metabolic syndrome and with glycaemia in middle-aged and older European men: the European Male Ageing Study

Background and aims Metabolic syndrome has been reported to have adverse effects on cognition although the results are conflicting. We investigated the association between metabolic syndrome and cognitive function in a population sample of middle-aged and older European men and whether any observed association could be explained by lifestyle or other confounding factors. Methods A total of 3369 men in the 40-to 79-year age group were recruited from population registers in eight centres for participation in the European Male Ageing Study. The subjects completed a questionnaire instrument and several cognitive function tests including the Rey-Osterrieth Complex Figure test, the Camden Topographical Recognition Memory test and the Digit Symbol Substitution Test. Metabolic syndrome data were assessed at an invited visit and metabolic syndrome was defined by the National Cholesterol Education Program's Adult Treatment Panel-III criteria. Associations between cognitive performance and metabolic syndrome were explored using linear regression. Results Complete cognitive and metabolic syndrome data from 3152 subjects were included in the analysis, of whom 1007 (32%) fulfilled criteria for metabolic syndrome. After adjustment for putative health and lifestyle con-founders, no significant associations were found between any of the cognitive function scores and metabolic syndrome or between cognitive performance and high-sensitivity C-reactive protein. Analysis of the individual metabolic syndrome factors, however, revealed an inverse association between the level of glucose and cognitive performance. Conclusions Metabolic syndrome was not associated with cognitive impairment in this population. Of the individual components of the syndrome, diabetes was associated with poorer performances in memory, executive functions and processing speed, associations that warrant further investigation. Copyright (C) 2010 John Wiley & Sons, Ltd.