Researchers from The George Institute for Global Health at the University of Oxford have found that while having high cholesterol levels does not influence your risk of aortic or mitral valve regurgitation, it does increase your risk of developing another major heart valve disease - aortic stenosis.
Aortic stenosis is the most common form of heart valve disease in developed countries and is thought to affect 2-7% of those over the age of 65 [1]. The disease is characterised by restricted blood flow through the valve, with affected individuals commonly experiencing symptoms such as chest pain, shortness of breath, heart palpitations and, in more severe cases, collapse and loss of consciousness.
The study team used a state-of-the-art method called Mendelian randomization to determine this causal effect. At fertilisation (the union of a human egg and sperm cell), we are all randomly allocated genes that are known to be associated with health-related characteristics in later life; in this case either normal or high cholesterol levels. Researchers were therefore able to categorise the study population by genetically-determined cholesterol level and then directly compare outcomes in terms of onset of aortic stenosis.
"Until recently, aortic stenosis has been widely considered a degenerative disorder associated with ageing with no recommended medical guidance for its prevention. Management has, therefore, focused largely on valve replacement surgery or catheter intervention," said Milad Nazarzadeh who led the research using data from the UK Biobank.
These management options are associated with significant complications and procedural costs estimated at £10,000 for valve replacement surgery and £16,000 for catheter intervention in the UK [2].
Professor Jeremy Pearson, Associate Medical Director at the British Heart Foundation, said: "Aortic stenosis is the narrowing of the aortic valve, the 'door' between the main pumping chamber of the heart - the left ventricle - and the body's main blood vessel - the aorta. This study shows that having high levels of 'bad' LDL cholesterol in the blood stream for a prolonged amount of time could increase your risk of developing the condition, putting extra strain on your heart to pump blood around the whole body.
"It's important that we know whether our cholesterol levels are in a healthy range or not. The good news is that getting access to these numbers is easy. Everyone between the ages of 40-74 is eligible for a free NHS health check, which assesses your risk of developing heart and circulatory diseases and includes a cholesterol measurement - a service we should all be taking advantage of."
Crucially, the evidence that high cholesterol is a risk factor for aortic stenosis presents clinicians with an opportunity to modify disease risk via preventative measures, for instance through the use of cholesterol-lowering medications such as statin therapy.
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The study was funded by the British Heart Foundation, the Oxford Martin School at the University of Oxford, and by the NIHR Oxford Biomedical Research Centre.
The paper in European Heart Journal will be available from this link: https://academic.oup.com/eurheartj/article-lookup/doi/10.1093/eurheartj/ehaa070
References
[1] Prevalence of heart valve disease
[2] Cost-effectiveness of aortic valve treatment
Notes for editors
"Plasma lipids and risk of aortic valve stenosis: A Mendelian randomization study," by Milad Nazarzadeh et al. European Heart Journal, doi:10.1093/eurheartj/ehaa070
MEDIA ENQUIRIES
Ana Bow-Bertrand (Communications Manager)
The George Institute for Global Health, University of Oxford
Tel: 07918 553680 | mailto:anastasia.bow-bertrand@georgeinstitute.ox.ac.uk
ABOUT
The George Institute for Global Health is an independent medical research institute aiming to improve the health of millions of people worldwide by generating effective, evidence-based and affordable solutions to the world's biggest health challenges. Headquartered in Sydney, with major centres in China, India and the UK, it has projects in more than 50 countries and affiliations with world-class universities. The George Institute UK was established in 2010 in partnership with the University of Oxford. Twitter @GeorgeInstUK Web georgeinstitute.ox.ac.uk
Milad Nazarzadeh is DPhil student at The George Institute for Global Health based at the University of Oxford, with a scholarship from the British Heart Foundation. His project focuses on the effect of blood pressure-lowering drugs and drug-drug interactions on the risk of type 2 diabetes through integrating epidemiologic and genetic data.
British Heart Foundation With donations from the public, the BHF funds groundbreaking research that will get us closer than ever to a world free from the fear of heart and circulatory diseases. A world where broken hearts are mended, where millions more people survive a heart attack, where the number of people dying from or disabled by a stroke is slashed in half. A world where people affected by heart and circulatory diseases get the support they need. And a world of cures and treatments we can't even imagine today. We are backing the best ideas, the brightest minds and the biggest ambitions - because that's how we'll beat heartbreak forever. Find out more at bhf.org.uk
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Journal
European Heart Journal