Question

Describe how the diet-heart hypothesis represents a multifactorial model for the etiology of coronary heart disease. In what way is the diet-heart hypothesis inconsistent with the epidemiologic triangle?

Answer 1

-- The diet-heart hypothesis links dietary fats, especially the saturated variety, to the incidence of cardiovascular disease in general and coronary heart disease (CHD) in particular.The saturated fat is the main cause of CHD related deaths,which attributed to the rise in the serum level of total cholesterol (TC)and the buildup of the artherosclerotic plaques characteristic of CHD.

-- Despite the skepticism of some statisticians and public health researchers, the theory quickly gained the acceptance among clinicians and led to the official recommendation by the American Heart  Association(AHA) that Americans limit their intake of saturated fat.On the contrary, an alternative theory implicating sugar as the primary culprit did not gain similarly large acceptance.

-- From this detailed analysis of the main dietary trials conducted over the last 30 years in the secondary prevention of coronary heart disease, it can be said that the older trials were conducted on low risk patients and used high fat diets comprising low saturated fat and cholesterol intake but very high polyunsaturated fat intake, particularly from the omega-6 fatty acid family.

-- These experimental diets were designed to reduce blood cholesterol and failed to improve prognosis.By contrast,recent trials were not primarily designed to reduce cholesterol, were conducted in medium and high risk patients and used low fat diets supplemented by omega-3 fatty acids from various sources.

-- In two of these trials, the consumption of natural antioxidants,oligoelements and vegetable proteins was increased .Recurrence rate was reduced in the range of 30-70%.

-- one conclusion from these well-conducted recent experiments on more than 3000 patients is that new and more specific dietary recommendations are clearly warranted in secondary prevention of coronary heart disease.

-- A traditional model of infectious disease causation, known as the Epidemiologic Triangle.The triangle consists of external agent, a host and an environment.In which host and agent are brought together, causes the disease to occur in the host.

-- Molecular genetics and advanced statistical methods, used for the study of heart disease and proteomics methods can lead to potential bio markers that can identify risks of CVDs, which in turn, can improve the prediction of acute cardiovascular events.

-- Pharmacogenetics can be useful in the development of more effective medications, and the management of CVD in children, young and adult population.Rheumatic heart disease,Chagas disease and infectious pericarditis and cardiomyopathies continue to cause a substantial burden of disease and death in some low and middle income countries.

-- A better epidemiological understanding of infectious forms of CVD in developing countries, and efforts to improve health cares are needed to prevent and treat these diseases such as HIV/AIDS, and Tuberculosis and other diseases such as malaria, typhoid and diabetes are also important for their association with CVD.In order to study CVDs in developing and developed nations, efficient epidemiological programs should be designed.