Background and aims: The relationships between blood pressure (BP) and cognition are complex and are still partly unclear. The impact of history of hypertension, present BP levels, and left ventricular hypertrophy (LVH) on cognition was investigated in a 10-year follow-up study of an aged population.
Methods: The population-based sample consisted of 75-, 80- and 85-year-old individuals at baseline (N=650). Their history of hypertension was investigated, and present BP values were recorded several times. Echocardiographic examinations were performed twice at 3-year intervals, and electrocardiography (ECG) at entry. Cognitive function was assessed by the Mini-Mental State Examination (MMSE) at baseline and at 10 years, and by the Clinical Dementia Rating (CDR) at baseline, at 1, 5 and 10 years.
Results: At baseline, elderly individuals with impaired cognition or dementia had lower BP, but thicker left ventricle posterior wall (LVPW), greater cardiac mass, and more often signs of LVH in ECG than those without cognitive deficits. Echocardiographic LVH, but not BP, predicted cognitive decline in a 5-year follow-up. Patients who died demented within 5 years were characterized by low BP and thin LVPW. Baseline BP and echocardiographic variables were not significantly different between those who had and had not cognitive decline at 10 years, but declining BP tended to precede cognitive deficits.
Conclusions: Results indicate that, the closer cognitive decline, the lower the BP, and suggest that, although LVH is a risk factor of cognitive decline, it loses its predictive value in old age.