Prevalence and Risk Factors of Covert Brain Infarction: a Community-based Cross-sectional Study

Background: Covert brain infarction (CBI) is common and poses a potential and non-negligible burden of disease worldwide. The prevalence and risk factors for CBI have been reported inconsistently in previous studies.

Aims: This study aims to ascertain the prevalence and risk factors of CBI and its imaging phenotypes in community-dwelling adults.

Methods: The study population was derived from the baseline survey of a population-based cohort from the Polyvascular Evaluation for Cognitive Impairment and Vascular Events study, involving adults aged 50-75 from Lishui City, Southeast China. The 3.0T Magnetic resonance imaging (MRI) was performed to access CBI and detect intracranial and extracranial vascular lesions. The prevalence rates of CBI and three imaging phenotypes were stratified separately by age, sex, atherosclerotic burden, and artery stenosis. The intracranial and extracranial atherosclerotic burden were graded by summing atherosclerosis scores. Multivariable logistic regression with stepwise selection method was used to identified independent CBI risk factors.

Results: A total of 2947 participants (mean age of 61.1 ± 6.6 years, 53.8% women) were included. CBI prevalence among study subjects was 9.6%, and the most common subtype was other chronic infarction (5.6%), followed by cavitatory lesions (4.6%) and acute cerebral infarction (0.5%). In multivariable analysis, older age (odds ratio [OR]: 1.59, 95% confidence interval [CI]: 1.40-1.83), hypertension (OR: 1.45, 95%CI: 1.08-1.94), higher levels of low density lipoprotein cholesterol (LDL-C) (OR: 1.17, 95%CI: 1.04-1.32), homocysteine (OR: 1.12, 95%CI: 1.01-1.23) and diastolic blood pressure (DBP) (OR: 1.22, 95%CI: 1.06-1.41), intracranial artery plaque (OR: 1.56, 95%CI: 1.16-2.10), severe extracranial atherosclerotic burden (OR: 6.57, 95%CI: 1.67-25.79) were associated with a higher CBI odds. There is a linear relationship between age, DBP, LDL-C and CBI odds, while homocysteine shows a nonlinear relevancy. Age, DBP, homocysteine and LDL-C elevation increase CBI risk.

Conclusions: CBI prevalence in this Chinese community-based population was not low. Age, hypertension, intracranial artery plaque, extracranial atherosclerotic burden, homocysteine, LDL-C and DBP were found to be the risk factors of CBI.