A commonly held belief amongst people inside and outside of medicine is that only about 50 percent of heart attacks are preventable. (A month ago my best estimate would have been 70 to 75 percent.) That is, through the perfect application of what we understand about coronary heart disease (CHD) about half of heart attacks could be prevented. The remaining half of cases are caused either by risk factors that we know about but cannot modify (e.g. a strong family history or genetic predisposition for CHD) or risk factors that we have not yet identified. But the truth is that nearly 90 to 95 percent of heart attacks are preventable. What’s more is that you can nearly eliminate your risk of heart attacks by controlling just 4 to 5 risk factors for CHD.
Two weeks ago I came across a series of articles that have opened my mind to a new approach to thinking about CHD risk reduction and have redoubled my enthusiasm for promoting preventive health care in younger people. The articles are not new, but somehow despite my interests in preventive health, had escaped my attention until now. This is the first in a series of blog entries aimed at changing the way most of us think about cardiovascular disease prevention. In this entry, I will frame these discussions by reviewing a seminal editorial entitled “Time to End Mixed Messages — And Often Incorrect — Messages about Prevention and Treatment of Atherosclerotic Cardiovascular Disease,” published in the Journal of American College of Cardiology in 2007 by Greenland and Lloyd-Jones. I commend everyone interested in these issues to read this article, which is surprisingly accessible to even non-cardiologists like myself (link below).
In their editorial, the authors summarize 4 key messages about cardiovascular disease prevention that we as health care providers and public health advocates must be giving to young people (taken verbatim from the article):
1. Heart attacks rarely occur in the absence of the major risk factors (adverse levels of blood cholesterol, blood pressure, smoking, diabetes). In at least one major health study, 90 to 100 percent of all CHD events occurred in people with at least 1 major CHD risk factor.
2. Absence of the major cardiovascular risk factors is highly protective against cardiovascular morbidity and mortality. Death from CHD is 77 to 92 percent lower among men and women without any major CHD risk factor compared to those with at least 1 risk factor.
3. Unfortunately, very few people in America have no major risk factors present. Less than 1 percent of men ages 35 to 74 have optimal risk factors for CHD. Among women ages 35 and 44, 9 percent have optimal risk factors and by ages 55 to 74 this number decreases to less than 1 percent. The percentages from using less stringent, clinical cutoffs are low but more encouraging (between 25 to 45 percent).
4. Elevated risk factors in young adulthood appear to be a major consequence of weight gain. Young people who maintain a stable BMI over time have minimal progression of risk factors. However, weight gain, accompanied by adverse risk factor progression, occurs in nearly 3 of 4 young adults.
The implications are these statements cannot be overstated. It means that if we could control just four or five risk factors for CHD — cholesterol, blood pressure, smoking, diabetes, +/- weight — we could nearly eliminate atherosclerotic cardiovascular disease in this country. This would be no small accomplishment: cardiovascular disease is the leading cause of death for both men and women in the United States accounting for over 850,000 deaths each year or nearly 1 death every 30 seconds.
While some may argue this analysis is overly-simplistic, it is also powerful in its simplicity. For example, we know that family history of early cardiovascular disease is a significant risk factor for CHD but it is a risk factor we can do nothing about. Furthermore, recent research shows that the effects of family history are largely through these other major risk factors for CHD because our genetic makeup predisposes us to adverse cholesterol, blood pressure and diabetes. Other risk factors such as physical activity and healthy eating, which we know are important determinants of health, are somewhat more difficult to quantify and use as risk assessment tools. The key is to have optimal levels of cholesterol, blood pressure, and weight; physical activity and diet can then be viewed as a means to achieving these more tractable benchmarks. It also debunks the notion of “old age” as a scapegoat for CHD. Age aside, controllable risk factors account for 90 to 95 percent of CHD.
If your head is spinning from all this, don’t worry, so was mine. In subsequent entries we will break down the data behind these assertions and begin to digest what exactly this all means for the individual person. In the mean time, spread the word — cardiovascular disease is largely preventable. The onus and opportunity for us is to make this potential a reality.