A powerful genetic predisposition to cardiovascular disease was overcome by low lifetime exposure to LDL cholesterol and systolic blood pressure in a naturalistic study conducted in nearly half a million people, Brian A. Ference, MD, reported at the joint scientific sessions of the American College of Cardiology and the World Heart Federation. The meeting was conducted online after its cancellation because of the COVID-19 pandemic.
This novel finding potentially opens the door to primordial cardiovascular prevention, the earliest possible form of primary prevention, in which cardiovascular risk factors are curtailed before they can become established.
“It’s important to note that the trajectories of lifetime risk for cardiovascular disease predicted by a PGS [polygenic risk score] are not fixed. At the same level of a PGS for coronary artery disease, participants with lower lifetime exposure to LDL and systolic blood pressure had a lower trajectory of risk for cardiovascular disease. This finding implies that the trajectory of cardiovascular risk predicted by a PGS can be reduced by lowering LDL and blood pressure,” observed Dr. Ference, professor of translational therapeutics and executive director of the Center for Naturally Randomised Trials at the University of Cambridge (England).
Together with an international team of coinvestigators, he analyzed lifetime cardiovascular risk as predicted by a PGS derived by genomic testing in relation to lifetime LDL and systolic blood pressure levels in 445,566 participants in the. Subjects had a mean age of 57.2 years at enrollment and 65.2 years at last follow-up. The primary study outcome, a first major coronary event (MCE) as defined by a fatal or nonfatal MI or coronary revascularization, occurred in 23,032 subjects.
The investigators found a stepwise increase in MCE risk across increasing quintiles of genetic risk as reflected in the PGS, such that participants in the top PGS quintile were at 2.8-fold greater risk of an MCE than those in the first quintile. The risk was essentially the same in men and women.
A key finding was that, at any level of lifetime MCE risk as defined by PGS, the actual event rate varied 10-fold depending upon lifetime exposure to LDL cholesterol and systolic blood pressure (SBP). For example, men in the top PGS quintile with high lifetime SBP and LDL cholesterol had a 93% lifetime MCE risk, but that MCE risk plummeted to 8% in those in the top quintile but with low lifetime SBP and LDL cholesterol.
Small differences in those two cardiovascular risk factors over the course of many decades had a big impact. For example, it took only a 10-mg/dL lower lifetime exposure to LDL cholesterol and a 2–mm Hg lower SBP to blunt the trajectory of lifetime risk for MCE in individuals in the middle quintile of PGS to the more favorable trajectory of those in the lowest PGS quintile. Conversely, with a 10-mg/dL increase in LDL cholesterol and 2–mm Hg greater SBP over the course of a lifetime, the trajectory of risk for people in the middle quintile of PGS became essentially superimposable upon the trajectory associated with the highest PGS quintile, the cardiologist explained.
“Participants with low lifetime exposure to LDL and blood pressure had a low lifetime risk of cardiovascular disease at all levels of PGS for coronary disease. This implies that LDL and blood pressure, which are modifiable, may be more powerful determinants of lifetime risk than polygenic predisposition,” Dr. Ference declared.
Discussant, professor of medicine at the University of Alabama, Birmingham, said that for her this study carried a heartening take-home message: “The polygenic risk score can stratify the population into different risk groups and, at the same time, lifetime exposure to LDL and blood pressure significantly modifies the risk, suggesting that genetics is not destiny, and we may be able to intervene.”
“To be able to know what your cardiovascular risk is from an early age and to plan therapies to prevent cardiovascular disease would be incredible,” agreed session chair, of the Sanger Heart and Vascular Institute in Charlotte, N.C.
, said the study introduces the PGS as a new risk factor for coronary artery disease. Focusing efforts to achieve lifelong low exposure to LDL cholesterol and blood pressure in those individuals in the top 10%-20% in PGS should provide a great absolute reduction in MCE risk.
“It potentially can give you a 30- or 40-year head start in understanding who’s at risk because the factor can be measured as early as birth,” observed Dr. Kathiresan, a cardiologist who is director of the Center for Genomic Medicine at Massachusetts General Hospital, Boston.
“It’s also very inexpensive: You get the information once, bank it, and use it throughout life,” noted, director of the Center for Cardiovascular Disease Prevention and professor of medicine at Harvard Medical School, Boston.
“A genome-wide scan will give us information not just on cardiovascular risk, but on cancer risk, on risk of kidney disease, and on the risk of a host of other issues. It’s a very different way of thinking about risk presentation across a whole variety of endpoints,” Dr. Ridker added.
Dr. Ference reported receiving fees and/or research grants from Merck, Amgen, Regeneron, Sanofi, Novartis, Pfizer, Eli Lilly, NovoNordisk, The Medicines Company, Mylan, Daiichi Sankyo, Silence Therapeutics, Ionis Pharmaceuticals, dalCOR, CiVi Pharma, KrKa Pharmaceuticals, Medtronic, and Celera.