Blood pressure and cognitive decline - the impact of hypertension over one decade.

BACKGROUND Midlife hypertension is a risk factor for cognitive decline in late-life but little is known about the impact of long-term hypertension on cognitive change over time. METHODS We examined blood pressure and cognitive function in 2777 participants (baseline: 2000-2003, 45-75 years, 48.4% men) from the Heinz Nixdorf Recall study. Blood pressure was assessed at three study visits and cognitive function was assessed at both follow-ups (mean follow-up: 5.1 years). Z-score differences in five neuropsychological tests, defining cognitive decline, were derived from linear regression models including age and education. The association of cognitive decline over 5 years and blood pressure over 10 years (classified as: normal blood pressure (>10 years, reference), prevalent hypertension (>10 years), incident hypertension t1 (>5 years), incident hypertension t2 (<5 years), temporary hypertension (at least one hypertensive reading)) was calculated using linear regression models resulting in coefficient b and 95% confidence interval. We calculated interactions with age (linear and with a cutoff at 65 years). RESULTS Participants with prevalent hypertension showed a greater cognitive decline in both verbal memory tests. Incident hypertension t1 was associated with a greater decline in the visuospatial organization test. There was no interaction with age. CONCLUSION This study showed that prevalent high blood pressure over 10 years is related to cognitive decline. Prevalent hypertension with longer exposure time may be more detrimental than temporary hypertension for cognitive function.