Relation of middle cerebral artery flow velocity and risk of cognitive decline: A prospective community-based study

•Evidence of the association between cerebral blood flow and dementia was sparse.•Flow velocity of LpMCA was inversely related to the global cognitive decline.•Cerebral blood flow velocity may impact the cognitive function. Hemodynamic parameters measured by the Transcranial Doppler Ultrasound (TCD) are related to cognitive impairment in many cross-sectional studies, but the longitudinal evidence is scarce. In this study, we aim to verify the association between flow velocity of Middle Cerebral Artery (MCA) and the longitudinal cognitive decline in community dwelling older adults. Participants were administered TCD examination at the baseline. The Peak Systolic Velocity (PSV), Mean Flow Velocity (MFV), and Pulsatility Index (PI) of MCA segments on left middle (LmMCA), left proximal (LpMCA), right middle (RmMCA), and right proximal (RpMCA) were obtained. Mini-mental state examination (MMSE) were conducted at both baseline and follow-up. One hundred and thirteen participants without dementia were followed up for 6.3 years in average. The mean annual rate of decline in the MMSE score was 0.15 (min to max: −1.0 to 1.2). LpMCA PSV (β = −0.0034, r = −0.231, P = 0.022) and LpMCA MFV (β = −0.0049, r = −0.217, P = 0.031) were inversely associated with annual rate of decline in the MMSE score after adjusting for age, gender, education year, APOE ε4, obesity, hypertension, diabetes mellitus, stroke, and coronary heart disease. Blood flow velocity of left proximal MCA was inversely related to global cognitive decline. Cerebral blood flow velocity may impact the cognitive function.