Associations between single and multiple cardiometabolic diseases and cognitive abilities in 474 129 UK Biobank participants

Aims Cardiometabolic diseases (hypertension, coronary artery disease [CAD] and diabetes are known to associate with poorer cognitive ability but there are limited data on whether having more than one of these conditions is associated with additive effects. We aimed to quantify the magnitude of their associations with non-demented cognitive abilities and determine the extent to which these associations were additive. Methods and results We examined cognitive test scores in domains of reasoning, information processing speed and memory, included as part of the baseline UK Biobank cohort assessment (N = 474 129 with relevant data), adjusting for a range of potentially confounding variables. The presence of hypertension, CAD and diabetes generally associated with poorer cognitive scores on all tests, compared with a control group that reported none of these diseases. There was evidence of an additive deleterious dose effect of an increasing number of cardiometabolic diseases, for reasoning scores (unstandardized additive dose beta per disease = -0.052 score points out of 13, 95% CI [confidence intervals] -0.063 to - 0.041, P < 0.001), log reaction time scores (exponentiated beta = 1.005, i.e. 0.5% slower, 95% CI 1.004-1.005, P < 0.001) and log memory errors (exponentiated beta = 1.005 i.e. 0.5% more errors; 95% CI 1.003-1.008). Conclusion Cardiometabolic diseases are associated with worse cognitive abilities, and the potential effect of an increasing number of cardiometabolic conditions appears additive. These results reinforce the notion that preventing or delaying cardiovascular disease or diabetes may delay cognitive decline and possible dementia.