Low diastolic pressure and risk of dementia in very old people: a longitudinal study.
OBJECTIVE
Midlife high blood pressure is linked to late-life dementia. We sought to investigate the temporal relation of blood pressure to the risk of dementia and Alzhei-mer's disease (AD) among older adults.


METHODS
A dementia-free cohort (n = 422) aged > or =81 years was followed for 3 years to detect dementia and AD cases (Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised criteria). The blood pressure was measured 4 times over a 9-year period starting from > or =75 years of age. The data were analyzed with Cox models controlling for potential confounders.


RESULTS
During the 954 person-years of follow- up, 89 subjects developed dementia (72 AD cases). Low diastolic pressure (<70 vs. 70-89 mm Hg) was associated with a multiadjusted hazard ratio of 2.13 [95% confidence interval (CI) = 1.05-4.32] for dementia and 2.16 (95% CI = 0.98-4.73) for AD occurring over a 6-to 9-year period, whereas high diastolic pressure (> or =90 mm Hg) was marginally related to a decreased hazard ratio of 0.58 (95% CI = 0.33-1.02) for dementia and 0.57 (95% CI = 0.30-1.09) for AD. Systolic pressure was not significantly related to dementia risk. Subjects who developed dementia had a greater decline in blood pressure than persons who did not, mainly during the 3-year period before dementia diagnosis.


CONCLUSIONS
Low diastolic pressure predicts the risk of dementia among very old people, and the blood pressure exhibits a substantial decline over around 3 years before the dementia syndrome becomes clinically evident.
Qiu
Chengxuan
C
Aging Research Center, Department of Neurobiology, Care Sciences and Society (NVS), Karolinska Institutet-Stockholm University, Stockholm, Sweden. chengxuan.qiu@ki.se
Winblad
Bengt
B
Fratiglioni
Laura
L
D000368:Aged / Q000502:physiology*; D000369:Aged, 80 and over / Q000502:physiology*; D000544:Alzheimer Disease / Q000453:epidemiology / Q000503:physiopathology / Q000523:psychology; D000959:Antihypertensive Agents / Q000009:adverse effects; D053327:Apolipoprotein E4 / Q000235:genetics; D001794:Blood Pressure / Q000502:physiology*; D015331:Cohort Studies; D003704:Dementia / Q000453:epidemiology* / Q000503:physiopathology* / Q000523:psychology; D005260:Female; D005838:Genotype; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D009483:Neuropsychological Tests; D016016:Proportional Hazards Models; D012306:Risk; D012959:Socioeconomic Factors; D013548:Sweden / Q000453:epidemiology; D014652:Vascular Diseases / Q000453:epidemiology
D000959:Antihypertensive Agents; D053327:Apolipoprotein E4