Vascular disease and cognitive function in older men in the Caerphilly cohort

OBJECTIVES: Stroke can impair cognitive function, but the associations between other manifestations of vascular disease and cognitive function have not been adequately studied in representative population samples of subjects. We report the associations between cardiac and peripheral vascular disease and cognitive function for a large representative sample of men in Caerphilly, South Wales, UK. DESIGN: The Caerphilly cohort is the basis of on-going studies of vascular disease, of cognitive function and of predictors of these. We have made intensive attempts to identify all cases of vascular disease: myocardial infarction, angina, ECG ischaemia, peripheral vascular disease (intermittent claudication) and stroke. Here we present data on associations between vascular disease and cognitive function. SETTING: The study is based upon a representative population sample of over 1,500 men in South Wales, aged 55-69 years when cognitive function was measured. The men, and hospital and GP notes relating to them, had been repeatedly examined for evidence of vascular disease during the previous ten years. MAIN OUTCOME MEASURES: Standard tests of cognitive function: the AH4, CAMCOG, MMSE and choice reaction time. RESULTS: After the omission of men who had had a stroke, we detected significant associations between cognitive function and the presence of angina, ECG ischaemia, past myocardial infarction and intermittent claudication. The strength of the associations between cognitive function and the various manifestations of vascular disease were similar, and the various cognitive function tests showed effects of similar size. Overall, cardiac and peripheral vascular disease is associated with a significant reduction in cognitive function equivalent to about one sixth of the standard deviation of a number of tests of cognitive function. The size of this effect is roughly equivalent to the decline in cognitive performance over five years of ageing. CONCLUSIONS: Subjects with evidence of cardiac or peripheral vascular disease have on average a significant reduction in cognitive function equivalent to about four or five years of additional age. The effect of long-term, low-dose aspirin on cognitive decline should now be tested.