Smoking, hypercholesterolaemia and hypertension as risk factors for cognitive impairment in older adults

Background: the prevalence of all types of cognitive impairment, including dementia, is increasing but knowledge of aetiological factors is still evolving. Objective: this study aimed to evaluate the association between cardiovascular risk factors and cognitive function in older persons. Design, setting and subjects: a population-based cohort design involving 2,312 men and women (aged 50-75) enrolled in the University of Edinburgh Aspirin for Asymptomatic Atherosclerosis trial. Methods: cognitive tests included the Mill Hill Vocabulary Scale, auditory verbal learning test (AVLT), digit symbol test, verbal fluency test (VFT), Raven's Progressive Matrices and the trail making test. A 'g' score (measure of general intelligence) was computed for each subject. Regression analysis was used to evaluate the association between relevant variables. Results: higher diastolic BP was negatively associated with AVLT (beta = -0.153, P < 0.01), and with an estimated decline on AVLT (beta = -0.125, P < 0.01). Smoking was negatively associated with all the cognitive variables except VFT. The total cholesterol level was not associated with cognitive function or estimated decline. Conclusions: smoking and elevated blood pressure may be risk factors for cognitive decline, and thus potential targets for preventive and therapeutic interventions.