Many years ago, at a time when we became acutely aware about “risk factors” in Coronary Heart Disease, my friend Dr. Anthony Gomes, Director of Cardiology, at the prestigious Mount Sinai Hospital in New York, was visiting Goa and dropped by. As long-lost friends we had a pleasant chat. But, after noticing that Dr. Gomes had put on a lot of weight, I asked pointedly. “Tony, how come you, a world-renowned cardiologist are neglecting yourself?” Without batting an eyelid Tony retorted, “I rely on my genes”. And then my scholar buddy elaborately apprised me of the intensive research in progress with regard to the role of our “genetic make-up” in warding off or making us vulnerable to heart attacks.
To convey better to my readers the role of genes in triggering or staving off a heart attack “let me begin at the very beginning.” I don’t know how many of you have heard of the famous “Framingham Heart Study” (FHS). What is it? It is a long-term, ongoing cardiovascular study on residents of the town of Framingham, Massachusetts, USA. The study began in 1948 with 5,209 adult subjects from Framingham, and is now on its third generation of participants. In 1948, FHS scientists and participants embarked on this ambitious project to identify “risk factors” for heart disease.
A “risk factor” is any attribute or characteristic of an individual that increases the likelihood of developing a heart attack. Today, the study remains a world-class epicenter for cutting-edge heart research. Prior to it almost nothing was known about the “epidemiology of hypertensive or atherosclerotic cardiovascular disease” and what really led to heart attacks and strokes. Much of the now-common knowledge concerning heart disease, such as the effects of diet, exercise, and common medications such as aspirin, is based on this study. It is a project of the National Heart, Lung, and Blood Institute, in collaboration with Boston University. Major findings from the FHS, are as follows: a) Cigarette smoking increases risk of heart disease. b) Increased “LDL bad cholesterol” and elevated blood pressure increase risk of heart disease. c) Exercise decreases risk of heart disease. d) Obesity increases the risk. The FHS also revealed that elevated blood pressure increases the risk of stroke and that in women after menopause, risk of heart disease is increased compared to women before menopause. The study also brought to light the fact that psychosocial factors affect risk of heart disease and that high levels of “good HDL cholesterol” reduce the risk of heart disease.
In recent years, scientists have been carrying out “genetic research” within the Framingham Heart Study. Inheritance patterns in families, heritability and genetic correlations, molecular markers and associations have been studied. The association studies include traditional genetic association studies and genome-wide associations.
Because of the exciting “genomic results”, the Framingham Heart Study has been described as “on its way to becoming the gold standard for cardiovascular genetic epidemiology”. However, clinically despite these what we know we are yet to unravel much as far as the secrets of the “genome” are concerned. But much effort is expended in this respect since the major goals of genetic studies of cardiovascular disorders are to develop improved preventive measures and more effective treatments. All we know for now is that there are “good genes” and “bad genes” as far as heart attacks are concerned and all of us hope that the “good genes” in us will far outweigh the deleterious effects of “bad genes.”
Recently a “polygenic risk score” has been devised to improve prediction of the risk of coronary heart disease (CHD). More than half of those who have a high “polygenic risk score” went on to develop heart attacks. Researchers from Massachussets General Hospital, in Boston, then used their previously developed “polygenic risk score”, and superimposed it on what is called the “healthy lifestyle score” derived from information on current smoking, weight, physical activity and diet. Those with a high “healthy life score” of 3 or 4 (with one point each for not smoking, not being obese, being physically active at least one day per week, and eating a healthy diet) were deemed to follow a favourable lifestyle. This cohort had a markedly lower incidence of heart attacks despite a high “polygenic risk score”. Conversely, the cohort with a zero “healthy life score” had the highest incidence of heart attacks. So here’s the message. First, the good news: “Healthy lifestyle” slashes the risk of coronary disease in people at “high genetic risk” for coronary events. And then the bad news: Those with “good genes” can’t expect their “genetic makeup” to offset intemperate habits.
Basically the foundation for prevention has to be a “healthy lifestyle”, because it makes a difference despite your genetic risk. While it is true that those with high genetic risk are not fated to have the problem because their genes are bad, those who have “bad genes” must know how important it is to lead a “healthy life style”.
Many of my patients, who have the history of heart attacks running in families, remain extremely disturbed almost anticipating a heart attack at any moment! All I tell them is, “God gave us the gift of life; it is up to us to give ourselves the gift of living well.”
(Dr. Francisco Colaço is a seniormost consulting physician, pioneer of Echocardiography in Goa.)
