Research conducted by the Department of Medicine and Therapeutics at The Chinese University of Hong Kong (CUHK) has shown a strong link between strokes and Alzheimer’s Disease.
The work reveals that cerebrovascular diseases (stroke) are closely correlated with Alzheimer’s dementia.
That means that patients with underlying Alzheimer’s dementia pathology have a 90% chance of developing dementia after a stroke.
However, the findings also suggest that improving vascular health can prevent or delay the onset of Alzheimer’s dementia.
Alzheimer’s dementia is the most common neurodegenerative disease worldwide with more than 35 million people, including 70,000 in Hong Kong, suffering from the disease.
Traditionally, Alzheimer’s dementia and cerebrovascular disease have been regarded as different diseases.
That has been challenged by a research team led by Prof. Vincent C.T. Mok, Division of Neurology, Department of Medicine and Therapeutics at CUHK.
They studied 1,013 Chinese people with an average age of 70 years who suffered from mild to moderate strokes in 2009 and 2010.
The result showed that among those who were found to harbour amyloid plaques in their brains, 90% developed dementia after a stroke.
Professor Mok said: ‘From the emergence of amyloid plaques in the brain, it takes 10 to 15 years more on average for the patient to develop dementia.
“However, a very minor stroke, or even a transient ischemic attack, is able to trigger dementia onset in patients with underlying amyloid plaques. In other words, a stroke is a catalyst of the process.
“Early studies recognized that cerebrovascular disease is present in as many as 50% of Alzheimer’s dementia patients. Therefore, we believe that 50% of dementia can be prevented or delayed if cerebrovascular disease can be prevented, despite the lack of effective treatment towards amyloid plaques.“
Dr Lisa Au, Clinical Tutor (Honorary), Division of Neurology, Department of Medicine and Therapeutics at CUHK, said: ‘The present study provides strong evidence that cerebrovascular disease triggers Alzheimer’s dementia. Maintaining vascular health will not only lower the risk of cardiovascular and cerebrovascular disease, but also prevent dementia.“
Dr Au said that preventive measures for cerebrovascular disease could help, including treatment of hypertension and dyslipidemia, stopping smoking, more physical activity, losing weight in the obese, a healthy diet and the use of anticoagulant drugs in subjects with atrial fibrillation.
The research team will now further investigate the pathology of Alzheimer’s dementia including estimating the prevalence of amyloid plaques among dementia-free elderly subjects and exploring whether or not certain drugs are able to clear up amyloid plaques or prevent dementia onset among those with amyloid plaques.