Prevalence and risk factors for progression of structural MRI markers of cerebral aging and vascular damage in high-risk non-demented adults

Abstract

Background We conducted a hospital-based study to investigate the prevalence and associated risk factors for progression of structural MRI markers of cerebral aging and vascular damage (white matter ischemia, cerebral microbleeds, and hippocampal volume loss) in high-risk non-demented adults. Methods We recruited 29 older non-demented adults (mean 73.8 ± 8.5 years, 66% male), who underwent two brain MRIs at least 1 year apart (mean 2 ± 0.9 years), from a University Hospital. The 3T MR images were examined for the severity of white matter hyperintensity (WMH, Fazekas score 0-3), cerebral microbleeds (CMB, Microbleed Anatomical Rating Scale), and hippocampal volume (HV, Scheltens score 0-4). Comparisons were made between the first and second MRI for each patient. Data were analyzed using univariate and multivariate regression analyses with SPSS. Ethical approval was obtained. Results In our 29 participants, 38% were current/ex-smokers, 83% had hypertension, 35% had diabetes mellitus, 21% had coronary heart disease, 65% had previous stroke, 62% had hyperlipidemia, and 7% had atrial fibrillation (AF). For medications, 35% were on statins, 69% on antiplatelet agents, and 10% on oral anticoagulants. MRI at baseline showed that 100% had subcortical WMH, 83% had periventricular WMH, 57% had CMB, and 48% had abnormal HV. During a mean interval of 2 years, 31% had more severe WMH, 28% had more CMB, and 38% had deterioration in their HV. Multivariate analyses found that age (p=0.004), diabetes mellitus (p=0.018), coronary heart disease (p=0.033), hyperlipidaemia (p=0.014), AF (p=0.046) and a stroke history (p=0.005) predicted progression of WMH. Patients with WMH also had a lower white cell count (p=0.018) and platelet count (p=0.016) compared with those who did not. Age or vascular risk factors did not predict the progression of CMB or HV. Use of antiplatelet agents, oral anticogulants or statins at baseline had no significant influence. Conclusion Amongst high-risk aging adults, structural MRI markers of cerebral aging and vascular damage are highly prevalent, and progression is common and rapid. Vascular risk factors are the major determinants of progression of white matter ischaemia, but not cerebral microbleeds or hippocampal volume loss. The effectiveness of vascular prevention on cerebral aging and vascular damage is yet to be proven.