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P3‐195: BRAIN VOLUMES DIFFER BETWEEN CAUCASIAN AND CHINESE COGNITIVELY NORMAL ELDERLY CONTROLS
Author(s) -
Zhang Linda,
TakFai Cheung Raymond,
Pa Judy,
Yokoyama Jennifer S.,
Lee Allen K.S.,
Chu Leungwing,
Rosen Howard,
Miller Bruce,
Fung Mak Henry Ka
Publication year - 2014
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2014.05.1285
Subject(s) - alzheimer's disease neuroimaging initiative , neuroimaging , confounding , medicine , cohort , ethnic group , psychology , disease , gerontology , cognitive impairment , neuroscience , sociology , anthropology
Background: White matter hyperintensity (WMH) load on T2-weighted MRI is a risk factor for cognitive impairment. Hypertension is associated with highWMH load, suggesting a vascular etiology. However, the relationship of blood pressure (BP) within the normal range and WMH is not established. Elevations in aortic hemodynamics precede the appearance of clinically-diagnosed hypertension. In normotensive individuals, noninvasivemeasurements of aortic hemodynamics provide information onvascular function. Early alterations in aortic hemodynamics may be mechanistically linked to the development ofWMH. In this context, the hormonal shifts during menopause accelerate vascular dysfunction in women, putting postmenopausal women at increased risk for both hypertension and WMH. Our objective was to determine the association between aortic hemodynamics and WMH in healthy, postmenopausal women with normal blood pressure. Methods: We examined 39 non-hypertensive postmenopausal women (age 6063 yrs; body mass index 2764 kg/m 2). Mean arterial blood pressure (MAP) was determined using a brachial arm cuff and was within normal range (8867 mmHg). Aortic hemodynamics were estimated using beat-bybeat tonometry (Sphygmocor). WMH was calculated from fluid-attenuated inversion recovery MRI using a semi-automated segmentation algorithm. WMH volume was divided by the total white matter volume to calculate WMH fraction in each subject.Results: Aortic hemodynamics included systolic BP (112610 mmHg) and diastolic BP (7467 mmHg). WMH fraction was positively associated with aortic systolic BP (r1⁄40.40;p<0.01) and aortic diastolic BP (r1⁄40.33;p<0.05). After adjusting for age, aortic systolic BP and WMH remained significantly associated (p1⁄40.03). Age and diastolic BP had a significant interaction (p1⁄40.02), with WMH fraction increasing less with aortic diastolic BP in older ages. Conclusions: In postmenopausal women with normal blood pressure, higher aortic systolic pressure was associated with greater WMH load. Because increases in aortic hemodynamics precede changes in brachial cuff BP measurements, our results suggest that monitoring aortic hemodynamics may identify individuals at accelerated risk for WMH and guide early treatment to reduce development of WMH and cognitive impairment.