No age is exempt from the lesions of arteriosclerosis if we consider the two groups. However, the disease is seen for the most part in persons past middle life. The relative frequency with which it is found in the different decades depends on so many factors that it is of no value to tabulate them. As has been stated, arteriosclerosis of all types is an involution process that advances with age. Longevity is a question of the integrity of the arterial tissue, and no one can tell what sort of "vital rubber" (Osler) any one of us has. However, many with poor tubing may make such use of it that it will outlast good tubing that is badly treated. Unfortunately we have no way of telling early enough with just what sort of arterial tissue we are starting life.
Sex
There is no doubt that men are far more prone to arterial disease than women are; all statistics are in accord on this point. This is explained by the greater exposure of men to those conditions of life which tend to produce circulatory strain, and so to produce arteriosclerosis, or vice versa. Arteriosclerosis in women is not often seen until after the fiftieth year. Cases of the most extreme grade of pipe stem arteries are, however, seen in old women, and calcified arteries are not hard to find among the inmates of an old woman's home.
Race
Some of the most beautiful examples of arteriosclerosis in this country are seen in the negro. Not only is this disease more frequent in the black race, but the age of onset is much earlier than in the Caucasian. The accidents of arteriosclerosis, viz., aneurysm, cerebral hemorrhage, etc., are more common among the negro males. The etiologic factors that are most often found in the history are the prevalence of syphilis and hard physical labor.
Occupation
Certain occupations have a distinct causal relationship to arteriosclerosis; among such are particularly those entailing prolonged muscular exercise, especially if much lifting is necessary. Every one is familiar with the phenomena accompanying the exertion of lifting. The breath is drawn in, the glottis is closed, and the muscles of the chest wall are held rigidly while the exertion lasts. This causes a great increase in blood pressure, and constant repetition of this will produce permanent high tension. In hospitals, the stevedores as a class have marked arteriosclerosis, and, almost without exception, they are comparatively young men. Occupations that are accompanied with prolonged mental strain, such as now occur to the heads of large manufacturing and financial institutions, also predispose to early arterial changes. Psychic activity, especially when it is accompanied by worry, is a potent factor in the production of the increased blood pressure which is the chief factor in producing arterial disease. It has been suggested that sexual continence in high-strung men produces changes in the nervous system which can conceivably lead to the production of high tension and further to arteriosclerosis. This, however, I can not think has any foundation in fact except in so far as such men are prone to live at high speed and wear themselves out sooner than the normal person. The sexual continence per se is not harmful. There are, however, men who seem not to be harmed by the constant wear and tear of our modern life. These are the exceptions.
Workers in factories where paint is made and the ingredients hand-mixed, are prone to develop arteriosclerosis early in life. It has been found that the laborers most apt to be victims of lead intoxication are those who are careless in their habits of cleanliness, particularly in regard to the fingernails. The continuous absorption of lead into the system, brings about a condition of hypertension that has its inevitable results.
The fact is that any occupation which entails either the absorption of toxic substances, or prolonged muscular labor, will hasten markedly the onset of arterial disease.