Oxford researchers have found that while having high cholesterol levels does not influence a person’s risk of aortic or mitral regurgitation, it does increase their 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 between two and seven percent of those over the age of 65. 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 team from the University of Oxford’s George Institute for Global Health, who were supported by the NIHR Oxford BRC, used a state-of-the-art method called Mendelian randomisation to determine this causal effect.
At fertilisation (the joining 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.
The 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.
Crucially, the evidence that high cholesterol is a risk factor for aortic stenosis presents clinicians with an opportunity to take preventative measures to reduce the risk of the disease, for instance through the use of cholesterol-lowering medications such as statins therapy.
As well as the Oxford BRC, the study was funded by the British Heart Foundation and the Oxford Martin School at the University of Oxford.
The paper was published in the European Heart Journal .