Systolic blood pressure at age 40 and cognitive function 25 years later: the Akershus Cardiac Examination (ACE) 1950 Study

Objectives: Hypertension in midlife is a risk factor for cognitive impairment. Still, the ideal midlife blood pressure (BP) remains unknown. We examined associations between different systolic blood pressure (SBP) levels at the age of 40–43 years and change in SBP over a 25-year period with cognitive function at age 62–65 years. Methods: We included 2424 individuals born in 1950 who had participated both in the Age 40 Program (1990–1993) and the Akershus Cardiac Examination (ACE) 1950 Study (2012–2015). The exposure was SBP at age 40–43 years and the outcome was cognitive function at age 62–65 years, assessed with Montreal Cognitive Assessment, Delayed recall trial from the Consortium to Establish a Registry for Alzheimer's Disease Word List Memory Task, and Trail Making Test part B (TMT B). Results: Participants were 40.1 ± 0.3 years old with mean SPB 128 ± 13 mmHg at the Age 40 Program, and 63.9 ± 0.6 years old with mean SPB 138 ± 18 at the ACE 1950 Study. Adjusted linear regressions showed no associations between SBP and subsequent cognitive function. In logistic regressions, individuals with SBP ≥140 mmHg, compared to individuals with SBP <120 mmHg (odds ratio 2.29, 95% confidence interval 1.28–4.10, P-value 0.005) had increased risk of an abnormal TMT B-score. Change in SBP during the 25-year follow-up was not associated with cognitive function. Conclusions: SBP ≥140 mmHg at age 40–43 was associated with reduced capacity on TMT B, a domain specific cognitive test sensitive to vascular impairment. No other associations were found between SBP, or change in SBP, and cognitive function.