PRospective Observation on CErebral microvaScular Structure and Function (PROCESS): a Population-based Prospective Cohort Study

Brain health is defined as normal brain structure, function and social adaptation and the absence of major brain diseases. Brain health is a lifespan-wide process that can be objectively measured and subjectively perceived and is determined by socio-psycho-biological factors. Currently, neurological disorders are the first cause of healthy life lost and the second leading cause of death globally, with nearly 9 million people dying each year from brain-related diseases.

Prevention of major brain diseases, including stroke and dementia, is first and foremost for brain health management. Notably, cerebral small vessel dysfunction may be an earlier pathologic change for the aforementioned major brain diseases. Cerebral small vessel dysfunction includes increased blood-brain barrier permeability, altered neurovascular coupling, decreased cerebral perfusion, decreased cerebral autoregulation, decreased cerebrovascular reactivity, and altered cerebral resting blood flow. Previous studies have shown that the prevalence of cerebral small vessel dysfunction was as high as 40% to 70% in people with illness but data from the general population remain scarce. Vascular risk factors such as aging, hypertension, diabetes, obesity, dyslipidemia, and insulin resistance have been known as important risk factors for the development of major brain diseases. Whereas, it is unclear whether vascular risk factors will cause these brain diseases through affecting cerebral small vessel function.

Thus, this prospective cohort study aims to assess the prevalence, distributional characteristics, and dynamic change of cerebral small vessel dysfunction, and to investigate the effect of vascular risk factors on cerebral small vessel dysfunction, cardiovascular and cerebrovascular diseases, cognitive dysfunction, and mortality in a Chinese community population.

In this study, a total of 3500 participants aged 50 to 75 years from villages and communities of Daxing District, Beijing will be enrolled using cluster sampling method. All the participants will be interviewed at baseline and followed up for 8 years. Baseline data will be collected through face-to-face interviews by trained interviewers using a standardized questionnaire. Baseline data include demographics, lifestyle, physical activity, medical history, cardiovascular risk factors, dietary habits, medication use, sleep status, novel coronavirus infection. Cognitive function assessment and neuropsychiatric examination will be performed based on various scales such as the Montreal Cognitive Assessment (MoCA) Scale and Mini-Mental State Examination (MMSE) Scale.

Additionally, heart function will be tested using electrocardiogram and color ultrasound. Peripheral vascular examination will be performed to measure ankle-brachial index. Fundus examination will be performed by trained ophthalmologists. Gait and eye movement examination will be performed by trained staff. The body composition will be tested using a body composition analyzer.