Background: The relationship between blood pressure levels and decline of cognition has been discussed previously, but little is known about the confounding effect of lifestyle factors, antihypertensive treatment and disease in the elderly.
Objective: To examine the association between systolic (SBP) and diastolic (DBP) blood pressure, changes of DBP and SBP and hypertension (HT) on cognitive function, while controlling for confounding factors.
Design: A longitudinal cohort study of men born in 1914 and residing in the municipality of Malmö studied at age 68 and 81 years.
Setting: Probands invited to a university clinic.
Subjects: One hundred and eighty-six out of 281 invited men still alive in 1995/6 participated in the most recent follow-up.
Main outcome: Change of the cognitive performance in the verbal (Paired Associates and Synonyms), spatial (Block Design and Benton Visual Retention test) and speed (Digit Symbol Substitution) functions.
Results: DBP by tertiles at 68 years, but not HT, was inversely related to verbal, spatial and speed performance at 81 years. Only spatial function was related to SBP at 68 years. The association between DBP and SBP by tertiles, and spatial functions (Block Design and Benton Visual Retention test) remained after controlling for education, marital status, smoking, alcohol and physical activity, and intermediates such as arteriosclerotic manifestations (block design, beta = 0.17; = 0.029) in multiple regression models. A decrease in DBP was likewise related to spatial (beta = 0.16; = 0.049) and speed performance (beta = 0.17; = 0.039) in the same regression model.
Conclusions: Evidence is found to support the hypothesis that hypertension, especially high DBP in late midlife, is associated with a decline in spatial performance of cognitive functions in elderly men.