The relationship between orthostatic hypotension and cognitive functions in the middle-aged and elderly people

Few studies have explored the relationship between orthostatic hypotension (OH) and cognition. The aim of this study was to examine the association of OH with cognitive functions and its modification effect by blood pressure status in the middle aged and the older. Participants were 819 community-dwelling middle aged and older persons without dementia. The cognitive functions were measured by means of logical memory test, D-CAT (digit cancellation test), verbal fluency test and MMSE. The OH was defined as a drop of 20 mmHg or more in systolic blood pressure or of 10 mmHg or more in diastolic blood pressure on standing from a seated position. Blood pressure (BP) was used to categorize participants as hypertensives or normotensives. Participants were divided into two OH groups (OH+ and OH–) and two BP groups (hypertensives or normotensives). ANCOVA, using age, sex, education, and usage of antihypertensive drugs as covariate, OH group and BP group as independent variables, and scores on the cognitive tasks as dependent variables, was conducted to investigate the effect of an interaction between OH and BP status. A significant interaction was shown for the score on logical memory test. The score of logical memory test in OH+ group was higher than that in OH– groups in the hypertensives condition. On the contrary, the score of logical memory test in OH+ group was lower than that in OH– groups in the normotensives condition. The conditions under which orthostatic hypotension decreased cognitive functions were discussed.