Kongcun Town Asymptomatic Intracranial Artery Stenosis study in Shandong, China: cohort profile

PURPOSE: The population-based Kongcun Town Asymptomatic Intracranial Artery Stenosis (KT-aICAS) study aims to investigate the prevalence of aICAS and major cardiovascular risk factors (CRFs) or biomarkers related to the development and prognosis of aICAS. PARTICIPANTS: The KT-aICAS study included 2311 rural residents who were aged ≥40 years and living in Kongcun Town, Shandong Province, China. Baseline examination was conducted from October 2017 to October 2018, during which information on demographics, socioeconomics, personal and family medical history, and lifestyle factors was collected through face-to-face interviews, physical examination and blood tests. aICAS was initially screened using transcranial Doppler examination and then diagnosed using magnetic resonance angiography. Atherosclerosis in carotid arteries was diagnosed via carotid ultrasonography. High-resolution MRI was further used to evaluate the vessel wall of aICAS. Neuropsychological assessments were performed in the participants diagnosed with aICAS and the age-matched and sex-matched controls. FINDINGS TO DATE: Of the 2311 participants, 2027 (87.7%) completed the diagnostic procedure and aICAS was detected in 154 persons, resulting in an overall prevalence of 7.6%. The prevalence of aICAS increased with advancing age from 5.1% in participants aged 40-49 years to 12.7% in those aged ≥70 years (p<0.001). aICAS was detected in 305 intracranial arteries, including 221 (72.5%) in the anterior circulation and 84 (27.5%) in the posterior circulation (p<0.001). In addition, major CRFs were highly prevalent among middle-aged and elderly rural dwellers who were free of clinical stroke. FUTURE PLANS: Follow-up examinations will be performed every 3 years following the baseline examination. This study will increase our knowledge about the natural history of aICAS and facilitate studies of aICAS-associated disorders among rural-dwelling Chinese adults, such as ischaemic stroke and vascular cognitive impairment. TRIAL REGISTRATION NUMBER: ChiCTR1800017197.