Blood plasma, normally clear, turns milky white when levels of cholesterol and other fatty substances become to high. A hand is placing a test tube in a rack next to another test tube; the plasma in one is clear, the other is milky white. A book titled "Cholesterol" is leaning against the rack. Verso: WHO/11920. General-cardiovascular disease. The Heart, A symbol of life. Statistics show that cardiovascular diseases are the leading causes of death in adults today, and their incidence seems to be on the increase. WHO has launched a number of projects in several countries to obtain more knowledge about the factors which affect the heart and blood vessels. I a special issue World Health illustrates aspects of the research that is going on in this field. Blood plasma, normally clear, turns milky white when levels cholesterol and other fatty substances become high. High levels of these substances have been associated with the development of coronary heart disease but more research is needed before their role is fully understood. Other factors suspected of playing a part in the development of coronary heart disease include lack of exercise, cigarette smoking and chronic mental stress. Original public domain image from Flickr