The Effect of Age on the Association Between Blood Pressure and Cognitive Function Later in Life

OBJECTIVES: To determine the prospective relationship between blood pressure (BP) and cognitive function across a wide age range. DESIGN: Prospective population-based cohort study. SETTING: The Rotterdam Study and the Leiden 85-plus Study. PARTICIPANTS: Three thousand seventy-eight men and women, initial age 55 to 84 from the Rotterdam Study and 276 men and women, initial age 85, from the Leiden 85-plus Study. MEASUREMENTS: Systolic BP (SBP) and diastolic BP (DBP) were measured at baseline, cognitive function was assessed at the end of follow-up using a dedicated neuropsychological test battery. The association between baseline BP levels and cognitive function later in life was assessed in 10-year age groups in the Rotterdam Study and in 85-year-olds of the Leiden 85-plus Study. RESULTS: In the youngest participants ( or = 75), higher SBP and DBP seemed to be related to better cognitive function at the end of follow-up. This effect appeared strongest in the highest age group (aged 85). CONCLUSION: High BP was associated with greater risk of cognitive impairment in persons younger than 75 but with better cognitive function in older persons. Age-specific guidelines for BP management are needed, because the current directive that "lower is better" may not apply to BP levels in the very old.