One would argue that if we were to hedge our bets on what will be the most likely cause of our death, heart disease would be a safe bet. In addition, as pointed above, in half of heart disease deaths, there are few warning signs and hence the high prevalence of sudden cardiac death. It is therefore paramount to work with our doctors to do everything we can to prevent heart disease. The good news is that there is ample evidence that if we do the right things, we can prevent heart disease.
We have touched on the importance of risk factors in general, but about heart disease specifically?
A study of men and women in three prospective cohort studies found that about 90 percent of CHD patients have prior exposure to at least one of the following major risk factors: high total blood cholesterol levels, or current medication with cholesterol lowering drugs, hypertension, or current medication with blood pressure lowering drugs, current cigarette use, and clinical report of diabetes. (JAMA. 2003;290:891–897.)
According to a case-control study of 52 countries (INTERHEART), nine easily measured and potentially modifiable risk factors account for over 90 percent of the risk of an initial acute myocardial infarction (MI). The effect of these risk factors is consistent in men and women across different geographic regions and by ethnic group, making the study applicable worldwide. These nine risk factors include cigarette smoking, abnormal blood lipid levels, hypertension, diabetes, abdominal obesity, a lack of physical activity, low daily fruit and vegetable consumption, alcohol over-consumption and psychosocial
index. (Lancet. 2004;364:937–952.)
Similar results have been shown by the Chicago Heart Association Detection Project in Industry, the Framingham Heart Study, the Atherosclerosis Risk in Communities Study, the Multiple Risk Factor Intervention Trial (MRFIT) Study, the Chicago Heart Association Detection Project, The Nurses’ Health Study, the Health Professionals Follow-up Study and The NHANES II Mortality Follow-Up Study.
What is the evidence for lifestyle modification interventions?
The Lifestyle Heart Trial (Ornish) provided conclusive evidence that intensive lifestyle changes can regress coronary atherosclerosis (Ornish D, et al. Can lifestyle changes reverse coronary heart disease? The Lifestyle Heart Trial. Lancet 1990 Jul 21;336(8708):129-33.)
The Multicenter Lifestyle Demonstration Project showed that significant improvements in diet (low fat, whole foods, plant-based), exercise, stress management, and social support can be achieved and maintained in heart disease patients, especially with spousal participation (Koertge J, et al. Improvement in medical risk factors and quality of life in women and men with coronary artery disease in the Multicenter Lifestyle Demonstration Project. Am J Cardiol. 2003 Jun 1;91(11):1316-22.)
A systematic review found that 4 lifestyle changes can affect mortality risk in CVD patients (Iestra JA, Kromhout D, van der Schouw YT et al. Effect Size Estimates of Lifestyle and Dietary Changes on All-Cause Mortality in Coronary Artery Disease Patients, A Systematic Review. Circulation. 2005;112:924- 934).
_ smoking cessation -- a 36% reduction in mortality risk
_ increased physical activity -- a 24% reduction in mortality risk
_ moderate alcohol use -- a 20% reduction in mortality risk
_ dietary changes -- a 44% reduction in mortality risk
A review of literature examining interventions to assist patients in achieving risk factor reductions through lifestyle change after myocardial infarction or coronary artery revascularization found that evidence supports: frequent follow-up, intensive diet changes, individualized and group exercise, coaching, group meetings, education on lifestyle modification and behavior change, and formal cardiac rehabilitation programs (Cobb SL, Brown DJ, Davis LL. Effective interventions for lifestyle change after myocardial infarction or coronary artery revascularization. J Am Acad Nurse Pract. 2006 Jan;18(1):31-9.)
Diet:
The Lyon Heart Study showed that a Mediterranean-type diet (which focuses on consumption of good fats, fruits, vegetables and whole grains) reduced cardiac death and non-fatal myocardial infarctions by 32% as compared to a typical “Western” diet (de Lorgeril M, Salen P, Martin JL, Monjaud I, Delaye J, Mamelle N. Mediterranean diet, traditional risk factors, and the rate of cardiovascular complications after myocardial infarction: final report of the Lyon Diet Heart Study. Circulation. 1999;99:779-785.
Smoking:
Several studies have shown that quitting smoking improves longevity and reduces recurrent heart related adverse events (Rippe JM, Angelopoulos TJ, Zukley L. The Rationale for Intervention to Reduce the Risk of Coronary Heart Disease. American Journal of Lifestyle Medicine 2007 1: 10-19.)
A systematic review of the effects of individual counseling on smoking cessation showed that individual counseling for 6 months or longer resulted in a 1.6 times greater likelihood of successful cessation (Lancaster T, Stead LF. Individual behavioural counselling for smoking cessation. Cochrane Database Syst Rev. 2002;(3)CD001292).
Exercise:
Several systematic reviews have shown the importance of exercise for patients with CVD (Taylor RS, Brown A, Ebrahim S et al. Exercise-based rehabilitation for patients with coronary heart disease: systematic review and meta-analysis of randomized controlled trials. Am J Med 2004; 116: 682-92.)
A prospective study of 773 men with known CAD followed for 5 years showed that those who engaged in light and moderate levels of activity had 58% and 53% lower mortality risks than those who engaged in minimal or no activity (Wannamethee SG, Shaper AG, Walker M. Physical activity and mortality in older men with diagnosed coronary heart disease. Circulation. 2000;102:1358-1363.)
Take home message: Spend time with your doctor discussing and quantifying your risks for heart disease. In addition, your doctor should address all of your risk factors for heart disease in a systematic manner by devising comprehensive preventive plans of action that should be regularly monitored and updated to address the major modifiable lifestyle factors. Remember that the focus of preventive medicine specialists is to spend their time on these important risk factors and helping you make changes to your lifestyle by engaging you in a long-term plan. The plan takes into account your environment, health behaviours and medical history so that the management is holistic.