The researchers at Edinburgh University believe that the link between blood fat and personality - and ultimately heart disease - may be more important and more complicated than has so far been suggested.
In a study of 1,592 men and women aged between 55 and 74 they found that men with raised levels of triglycerides - essential body fats - were more likely to be hostile and to have 'denigratory attitudes' to others.
They studied personality and blood fat after it was discovered that people who had lowered their levels of another blood fat, cholesterol, possibly reduced their risk of heart disease but appeared to increase the risk of dying a violent death from accident or suicide.
People with higher levels of triglycerides are likely to eat a lot, in that they take in high levels of calories. Triglycerides are a group of simple fats manufactured in the body. They are an essential part of cell membranes and are also involved in the control of the metabolism. They are broken down from fats in the diet, from carbohydrates like bread and potatoes and from alcohol.
They are a form of fat which responds to a variety of influences. Raised blood triglyceride levels can be measured after eating a fatty meal, in people who have drunk a lot of alcohol and in response to stressful experiences like accidents.
The Edinburgh scientists, writing in the Lancet, think that the drugs used to reduced cholesterol might raise the triglyceride levels, but they say this is not the whole explanation.
Dr Gerry Fowkes, director of the Edinburgh Artery Survey, says that the raised levels could have the effect of predisposing people to 'overt aggression' thus leading to a greater risk of violent death.