OBJECTIVESWe investigated the association between the fall of nocturnal blood pressure (BP) and cognitive impairment in elderly subjects.

METHODSThe study was a cross-sectional survey of 204 elderly subjects who had no cerebrovasucular episodes. Ambulatory BP monitoring and assessments of cognitive functions using the Mini-Mental State Examination (MMSE) were performed at the subjects' homes. We classified, the subjects treated with antihypertensive drugs into three groups: non-dippers (nocturnal fall<10% of the mean day diastolic BP; n=51), normal dippers (10% to less than 20%; n=58), and extreme dippers (20% or more; n=17). The subjects not treated with antihypertensive drugs were also classified as non-dippers (n=40), normal dippers (n=24), and extreme dippers (n=14).

RESULTSThe mean age of participants was 75.2±7.2 years, and 126 (61.7%) were being treated with antihypertensive drugs. In the group of antihypertensive drug users, the number with MMSE≤23 was 30 and the adjusted odds ratio for cognitive impairment in those with an extreme dip in diastolic BP (DBP) was 4.18 (95% CI, 1.07-16.40) in reference to the normal dippers. In contrast, no association was observed between cognitive function and nocturnal BP fall in the group no using antihypertensive drugs.

CONCLUSIONSCognitive impairment was associated with an extreme dip in DBP in the antihypertensive drug users only. It remains to be seen whether careful monitoring of nighttime BP as well as daytime BP may reduce the risk of cognitive impairment in antihypertensive drug users.