On World Heart Day 2023, Dr Ramesh Menon, Associate Director – Personal Genomics & Genomic Medicine, MedGenome and Dr Muralidhar Kanchi, Director (Academic), Narayana Institute of Cardiac Sciences, Bengaluru explains how our genes could be a “risk-enhancing” factor for Coronary Artery Disease (CAD)
Nearly 25 per cent of the world’s population is South Asian and this region is also infamous for having higher than average incidence of coronary artery disease. About 60 per cent of the global incidence of heart disease is among South Asians[1]. Over the years, research has shown that this isn’t a result of lifestyle factors al one. As the scientific community puts it – our genes could be a “risk-enhancing” factor for CAD.
South asia’s track record with CAD
The numbers paint a clear picture, revealing an undeniable truth. India’s prevalence of CAD is pegged at about 54.5 million, with Indians having 3 to 4 times the risk compared to Caucasians[2].
Source: Stanford Health Care
People of South Asian ethnicity, whether they live in the sub-continent or overseas, share the same genetic risk of CAD. For instance, the British Heart Foundation says that coronary heart disease risk could be as much as 50 per cent higher in first-generation South Asians compared to their Caucasian/European descent counterparts in the UK[1]. In the US, it has been reported that South Asians have a higher likelihood of needing a CABG (Coronary artery bypass grafting).
South Asians have a higher risk of an earlier onset of cardiometabolic risk factors and other conditions known to elevate the risk of cardiac disease. This includes hypertension, insulin resistance, and central obesity (fat around the stomach)[2]. South Asians also tend to have visceral fat around the liver and heart. Diabetes, a condition that the population is more vulnerable to, is associated with low levels of good HDL cholesterol and high levels of triglycerides. These in turn further elevate the CAD risk[3].
The genetic risk for CAD
Genetic research has revealed that our risk of heart disease isn’t dependent on just 1 or 2 genes or a small number of them. Instead, there are multiple genes that work in tandem to influence a person’s risk of developing a certain condition.
The Genome-wide polygenic score for CAD (GPSCAD) predicts the risk levels of the individual being tested, for developing CAD. Your score shows your genetic risk of developing CAD as average, moderate, or high. For instance, Kardiogen, the genetic test from MedGenome has been validated for the South Asian population[4] and the PRS score it gives, is calculated using information on over 6 million genetic markers linked to the disease. The CAD PRS has a 50 per cent sensitivity rate for young onset CAD and can, 90 per cent of the time, predict high risk for individuals who have a coronary event before turning 45.
While blood pressure or your cholesterol levels, need regular monitoring. What makes the case for genetic screening tests even more compelling is that they don’t need to be repeated. Genetic tests do not replace the existing screening tests, but they provide greater insights for a holistic analysis of your health for early intervention.
Improving the odds
While the odds may seem like they’re stacked against South Asians there are some things that one can do to lower the overall risk of CAD.
- Control lifestyle factors. This means quitting smoking, leading an active lifestyle, and exercising regularly, eating a healthy balanced diet, and maintaining a healthy body weight in the ‘normal’ BMI range for your height.
- Monitor health indicators that have an association with CAD. These include your cholesterol levels, blood sugar levels, and blood pressure.
- Keep other comorbid conditions in check. If you are diabetic or have hypertension, be sure to follow the recommended regimen to keep your condition in control. Unmanaged hypertension and diabetes will elevate your risk of CAD.
- Get genetic screening to find out your PRS. With this information, you can skip the suspense and understand if you require cardiac health checks more often or whether you should consult a doctor about medication to reduce the risk of adverse cardiac events.
With these changes, you can make good cardiac health a habit and lower your overall risk of CAD. Because while you may have been born with a greater risk of developing CAD, there’s plenty you can do to ensure you don’t give in to the odds.
References
[1] https://www.acc.org/Latest-in-Cardiology/Articles/2019/05/07/12/42/Cover-Story-South-Asians-and-Cardiovascular-Disease-The-Hidden-Threat
[2] https://www.ahajournals.org/doi/10.1161/CIRCOUTCOMES.118.005195 and https://www.sciencedirect.com/science/article/pii/S0735109720356448?via%3Dihub
[3] https://www.bhf.org.uk/informationsupport/heart-matters-magazine/medical/south-asian-background
[4] https://link.springer.com/article/10.1007/s11883-023-01110-5
[5] https://www.bhf.org.uk/informationsupport/heart-matters-magazine/medical/south-asian-background
[6] https://www.sciencedirect.com/science/article/pii/S0735109720356448?via%3Dihub
[7] https://www.sciencedirect.com/science/article/pii/S0735109720356448?via%3Dihub