American Heart Journal July, 1964, I’olwne 68, Number 1

Editorial

The mortality rate from heart disease

Maurice Campbell, O.B.E.

London, Engluntl

T he large increase in the death rate from heart disease since about 1924,

and especially in that from coronary heart disease, is one of the most striking features of recent medical statistics. In the first1 of two papers in the British Medical Jour- nal, I discussed the changes that have taken place, and in the second paper? I brought forward evidence that the in- crease in the death rate from heart disease as a whole may be due entirely to the older age of the population, and that the much greater increase in the death rate from coro- nary heart disease is due mainly to increas- ing medical knowledge and more accurate diagnosis.

I summarized the crude annual death rates per million persons living, as reported bv the Registrar General. All the figures discussed are for men and women com- bined, although some of the trends dis- cussed would have been even more striking for the men alone. The death rates from all diseases of the circulatory system, from all diseases of the heart, and from vascular lesions of the central nervous system are considered, from 1876 shortly, and from 1891 through 1960 more fully.

The death rates from the main sub- divisions of diseases of the heart also are summarized. Changes in the Registrar-

General’s classification are discussed, but do not seem to be an important cause of the findings. Changes in medical views and knowledge seem to be more important and explain the rise in registered deaths from valvular disease of the heart up unti! 1917, and the fall especinll!: after 1931, and much, if not all, of the rise in deaths from coronaq heart disease since 1924.

The death rate from all diseases oj’ the heart changed veq- little from 1876 to 1920, and probably from 1850. About 1924, it began increasing rapidly, and rose from 100 to 263 per cent by 1952, since when it has shown some signs of settling at the higher level.

The recorded death rate from coronary heart disease started increasing about the same time in geometrical rather than in arithmetical progression. This rise is still continuing; although largely after 1940, and entirely after 1951, it must be due to a change in diagnosis, since it is entire11 balanced by a fall in the deaths attributed to other myocardial disease. The original level was so low that the deaths from coro- narv heart disease were not of much arith- me&al importance until about 1940.

The death rate from cerebrovascular lesions behaved in much the same way as that from all diseases of the heart, and the

From the Cardiac Department, Guy’s Hospital, and the Institute of Cardiology, London. England. Received for publication Nov. 21, 1963.

2 Campbdl

increase was of the same order but rather less--from 100 to 220 per cent instead of from 100 to 263 per cent.

In the second paper, I explained what I think to be the main cause of this large in- crease in deaths from all forms of heart disease, and presumably of those from cerebrovascular accidents also. Because nothing has been done to reduce the risks of dying from most diseases of the heart after middle age, and so much has been done to reduce the risk of dying from in- fectious diseases, mainly it1 infancy and childhood, it is inevitable that the death rate from diseases of the heart must in- crease; these two changes have not been connected so closely as they should have been, because of the interval of 40 years between then.

The death rate from all causes changed only slightly from 1838, when the sta- tist&s of the Registrar General started, until 1880; and over all this period it averaged 21.7 per 1,000 persons living. After 1880, it fell somewhat and was about 18.7 per 1,000 for the years 1881-1895. It then fell much more rapidly until 1925, when it was 10.7 per 1,00&-a little less than half of the level maintained from 1838 to 1880. Since 1926, it has fallen onI1 slightly, and is not likely to fall much until something more can be done about deaths from heart disease and cancer. Indeed, sometime it is likely to rise when there is no longer a rising birth rate to offset the in- creasing aqe of the population.

Most ofL the lives saved were those of infants and children dying from infective gastroenteritis and other infectious dis- eases, and those of young adults dying from tuberculosis. I calculated their average age at death as between 16 and 20 years: I used the latter figure but, in retrospect, think that the former is probably more accurate. The mean age at death of subjects

dying from heart disease has been increas- ing from 59 years in 1910, to 73 l’ears in 1959, so that in the earlier years of our period there would be an interval of 40 vears between the times when rnan\~ sub- jects who might have died from infectious diseases did, in fact, die from heart disease.

011 the assumption (1) that the fall ill the death rate was mainly from 1885 to 1925 (because the fall was gradual ad small in 1880-1895), and (2) that those who ultimately died from heart disease did so 40 years later than the!. would have from infectious diseases, a large increase in the death rate from heart disease should have been expected from 1925 to 1965. Making these asstnmptions but distribut- ing the new deaths front heart disease nlore widely at various ages (instead of taking the mean age), I have calculated the “es- pected” death rate front all diseases of the heart from 1880. It rose very slowly until 1917, rather more quickly from then until 1937, and much niore quickly from 1927 to 1973, and then slowly but hardlqv sig- nificantl>. until 1990. The close agreenlen t of these calculated figures with the recorclcd death rate from 1880 to 1960, suggests that all of the increase in the recorded death rate front diseases of the heart, in- cluding coronary heart disease, could be due to this cause. I consider that the ill- creasing age of the population caused b\ the lives saved because of the better control of infectious diseases is the rmain, if not the only., reason for the large increase in the deaths front all heart disease since about 1924.

REFERENCES

1. Campbell, M.: Death rate from diseases of the heart: 1876 to 1959, Brit. M. J. 2528, 1963.

2. Campbell, M.: ‘The main cause of increased death rate from diseases of the heart: 1920 to 1959, Brit. M. J. 2:712, 196.1.