Elevated BP and cerebral small vessel disease prevalent in HK’s middle-aged and older residents

According to local data presented at AIM 2024, approximately two-thirds of middle-aged and older residents in Hong Kong have systolic blood pressure (SBP) >120 mm Hg. A high prevalence of cerebral small vessel disease (SVD) is also found in this population.

Over the past three decades, the increasing trend in neurological conditions, such as stroke and dementia, mirrors global demographic changes, ageing populations and increased exposure to environmental, metabolic and lifestyle risk factors. Certain modifiable factors, including hypertension, obesity, diabetes and traumatic brain injury, contribute to the risk of both stroke and dementia. [Lancet Neurol 2024;23:344-381]

To examine the interplay between genetic and environmental factors that contributes to brain disease development from mid-life onwards, researchers from the Chinese University of Hong Kong (CUHK) and Massachusetts General Hospital, Boston, Massachusetts, US, initiated a population-based cohort study in 2019 to evaluate brain health among middle-aged and older residents in Hong Kong.

“As of 24 May 2024, the study enrolled 4,755 individuals [male, n=2,154] aged 40–74 years without a history of brain disease, reaching 95.1 percent of the recruitment target [n=5,000]. All participants completed health questionnaires, and 4,164 underwent baseline physical assessment, blood tests, biobanking, carotid duplex and fundoscopy, and cognitive test with Montreal Cognitive Assessment [MoCA]. Brain MRI scan was performed in 970 participants,” said Professor Thomas Leung of the Department of Medicine and Therapeutics, CUHK.

“In primary analysis, 66.2 percent of participants were found to have SBP >120 mm Hg, while 25.9 percent had SBP >140 mm Hg. HbA_1c >6.5 percent and LDL-cholesterol >4 mmol/L were found in 8.8 percent and 11.3 percent of participants, respectively,” Leung reported. “Of these participants, 73.3 percent had white matter hyperintensity, 48.4 percent had asymptomatic carotid plaque, 8.9 percent had intracranial aneurysms, and 5.7 percent had asymptomatic intracranial atherosclerotic disease. The rate of cognitive impairment [MoCA <7^th percentile] was 6.8 percent.”

“Brain MRI demonstrated mild and moderate-to-severe SVD in 55 and 11 percent of participants, respectively. All cases were in subclinical stages. Additionally, 21 percent of participants had cerebral microbleeds,” he continued.

“Individuals with subclinical SVD may develop hypertension that can go undiagnosed due to BP variability. For example, during 24-hour BP monitoring, a 66-year-old male participant with subclinical basal ganglia infarct showed normal BP in the morning but experienced mid-day surge to 200 mm Hg,” said Leung.

Brain Care Score for primary care setting

The study also evaluated a prototype Brain Care Score – a tool designed to score individuals’ brain health in the primary care setting. Developed by the researchers at Massachusetts General Hospital, the scoring tool involved 12 modifiable risk factors in three categories, including cardiovascular risks (eg, BP, HbA_1c, BMI, cholesterol), lifestyle factors (eg, exercise, sleep), and social factors (eg, stress, socialization). [Lancet Neurol 2022;21:961-962; https://www.massgeneral.org/neurology/mccance-center/research/brain-care-score] “The maximum Brain Care Score is 19, with a higher score indicating lower likelihood of brain diseases,” said Leung.

In cross-sectional analysis, higher Brain Care Score was associated with lower degree of carotid plaque stenosis (β, -0.017; p=2.90 x 10^-39; adjR², 0.0432) and better MoCA score (β, 0.202; p=2.82 x 10^-18; adjR², 0.0192). [Leung T, AIM 2024]

“Longer-term follow-up will confirm preliminary data on the Brain Care Score. Prototype refinement is also required,” Leung added.