Cardiovascular diseases - the epidemic of our century. Why? And their future developments?

The early and mid-19th century witnessed a massive and constant increase in the incidence of cardiovascular diseases in the industrialized world and a drop in the rate of mortality caused by infectious diseases, infant mortality and diseases related with the lack of food and bad hygiene.
This phenomenon followed a rapid increase in the incidence of arteriosclerotic diseases, which cause myocardial infarction and stroke. The probability of being affected by arteriosclerosis and its clinical consequences did not increase later in the century and it reduced during the last decades.
However, the disease’s predominance maintained very high levels to the point that, today, about half the number of deaths is due to cardiovascular causes (more than twice the deaths caused by tumours). Ischaemic heart disease, the most frequent cardiovascular pathology, is today the most frequent cause of death in the world, according to recent data collected by the World Health Organization (WHO) and the fifth cause of disability. The WHO believes that it will remain the primary cause of death and will also become the primary cause of disability in 2020.
Why is the control of the disease still so unsatisfactory despite the efforts and resources used to implement the prevention and availability of effective drugs? The reasons are many: the first is the increased average life span - longer lives expose people to degenerative diseases such as arteriosclerosis, which are more frequent in the middle and old aged; the second is that there are fewer deaths caused by acute cardiac incidents, thanks to the effective treatments available, but one continues to live with a sick heart; and, the third is that the risk factors of arteriosclerotic diseases are controlled very little and poorly.
What is taking place in developing countries clearly shows the importance of risk factors.
These countries are now undergoing the same process the industrialized world experienced during the first half of the last century - an exponential increase in the incidence of cardiovascular diseases. The reasons too are more or less the same, multiplied by the acceleration that characterizes social processes in our day. Variations in lifestyle are the main cause of arteriosclerosis’ epidemiologic nature – urban migration associated with inactivity, smoking, diets with a predominance of animal fat and proteins and stress.
Populations with an unaltered genetic heritage, hence with an unchanged tendency to be affected by cardiovascular diseases, fall sick more often when they are exposed to factors that encourage the onset of the disease.
For example, when ethnic groups such as Japanese or Latin Americans, who have a relatively low predominance of cardiovascular diseases in their countries, live in the US, where the predominance of the disease is high, they acquire a probability of being affected by the disease that is similar to the American population.
Another example: a recent study (the Strong Heart Study) conducted in over 3000 Red Indians in four geographically distant reservations in the United States, noticed that 51% was diabetic. In a population selected by repeated famine, which has developed a genetic and metabolic complement based on energy conservation (also through the action of insulin), a plentiful and fatty diet leads to diabetes, obesity and hypercholesterolaemia - all factors that encourage arteriosclerosis.

Yet again the Afro-Americans are more prone to arterial hypertension than the whites. Most probably, being more selected by conditions of lack of water and dehydration, they retain sodium more effectively (hence by osmosis, water too), a factor that encourages the development of hypertension, which in turn encourages arteriosclerosis. Hence the control of risk factors is of crucial importance in cardiovascular prevention. I mentioned behavioural risk factors such as smoke, diet, inactivity and stress.

For each of these we know the mechanisms by which they damage blood vessels or encourage damage induced by other factors, and epidemiological studies have proved for certain the advantages of their removal. There are no drugs to control these risk factors. They are behavioural, hence behavioural patterns must be changed and lifestyles too.
Other factors are more related to individual biological profiles such as high levels of blood cholesterol, obesity, arterial hypertension and diabetes mellitus. They can all be partly kept under check also behaviourally, (through diet and exercise) but they are mainly controlled with antihypertensive drugs, statins, polyunsaturated fats ù-3 etc…. However the results achieved through educational campaigns and drugs are entirely unsatisfactory.

The Table refers national data on the distribution of risk factors in our country, collected for the National Epidemiological Observatory by the Istituto Superiore di Sanità [Superior Health Institute] and by the Associazione Nazionale Medici Cardiologi Ospedalieri [National Institute of Hospital Cardiologists] (ANMCO).

Evident arterial hypertension and marked hypercholesterolaemia are present respectively in over 30% and 25% of Italians. Excess weight, inactivity and smoke have important repercussions throughout the country, and especially in the south.
The treatment’s only partial effectiveness appears quite clear from the data presented by the Observatory. About half the hypertense patients and two thirds of the hypercholesterolaemic ones are not treated.
The results in terms of a reduction in the target parameter are unsatisfactory in about half the treated patients. It is clear that there is still a lot more to be done.

Luigi Tavazzi
Policlinico S.Matteo
Divisione di Cardiologia
Pavia