a Department of Social and Preventive Medicine, University of Manchester and Salford Health Department.
b Mental Health Research Fund, Department of Social and Preventive Medicine, University of Manchester.
Remarkable changes have occurred in the sex and age incidence of peptic ulcer in North-West Europe. The fluctuations over the previous hundred and fifty years were studied by Jennings (1940).1 He examined the incidence of perforations, which provide perhaps the most uniform index of the incidence of ulcers for the total period. His interpretation suggested that during this period there had been three observable syndromes: perforations of acute gastric ulcers in young women; perforations of duodenal ulcers in young and middle-aged men; and perforations of gastric ulcers in older men.1
Perforations began to be noted with increasing frequency at the beginning of the 19th century. Half of all perforations were then in young women in their twenties, and these reached a peak in the latter half of the century. They seemed to be acute gastric ulcers, which caused death from perforations near the cardia, or from haemorrhage.1,2 By the end of the century this condition had begun to disappear. But even in 1905 the Registrar General was able to write: Gastric ulcer does not appear frequently as a cause of death until the attainment of the reproductive period, when the female rate greatly exceeds the male, while at later ages the male rate is in excess.3
The common perforations of today made an appearance only at the beginning of the 20th century; these are juxta-pyloric ulcers occurring mainly in young and middle-aged men.4 Studies up to 1955 show a continuing trend of increase in perforations of peptic ulcers in men.5,6 These changes in perforations were reflected in the death-rates. Because of the sharp rise in morbidity and mortality during this century, peptic ulcer, particularly of the duodenum, has earned a place as one of the diseases of civilization.
In the last decade, however, there were signs that the volume of peptic ulcer had at last reached a peak and was beginning to fall. A halt in mortality from gastric ulcer was noted in the early 1950s, and it then seemed possible to ascribe this to better treatment.7 Subsequently the death-rate has continued to fall, and sickness statistics show the same trends. The decline is found in sickness-rates reported from general practice, from the Army, and from insurance certificates.811
Trends for duodenal ulcer are similar, but follow about five years behind. In the mid 1950s death-rates reached a plateau, and then began to fall. This fall can also be seen from the census of clinically diagnosed peptic ulcers in York, and from the duration and the number of spells of sickness absence.12 As yet it does not appear in statistics of the last decade from general practice and from the Army, both of which showed stable rates.810
All these trends together suggest that we are observing a recession of the peptic-ulcer syndrome. This has affected the age-groups unequally. Since the war, mortality from gastric and duodenal ulcers has declined in young men and women, although recently it was still rising at ages over 65 (Figure 1a, b, c, d). One possible explanation is that the fluctuations in peptic-ulcer rates represent a cohort phenomenon, and that each generation has carried its own particular risk of bearing ulcers throughout adult life. In order to examine this hypothesis the experience of each generation or cohort must be followed separately through its life-cycle.
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Support for the cohort hypothesis can be found from age changes over time in the manifestations of peptic ulcer. These are apparent in three sets of datanamely, age-specific death-rates, perforations, and social-class death-rates.
Death by age and sex
The data for peptic-ulcer mortality can be cast in the form of a cohort analysis by plotting the deaths in each age-group by year of birth instead of by year of death. In this way the death-rates of separate generations can be followed as they grow older through the years. Technical and theoretical questions raised by this method have been discussed by others.1316 In Figure 2 the points along each curve represent the deathrates of successive generations at given ages. The death-rates of a particular generation, as it grows older, are read by passing vertically from curve to curve, along the broken lines which join the points plotted above the year of birth of the generation.
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Perforations
The average age at which perforations occur has increased year by year. This is shown in the figures for Glasgow from 1924 to 1953, and also by those for Aberdeen and North-East Scotland from 1946 to 1956.5,6,17 This upward shift of the mean age of perforations concords with the ageing of the generations exposed to the highest risks.
A recent survey of perforations in two hospitals in the South of England suggests that these are becoming fewer each year, and the reduction is particularly marked at young ages.15 This trend towards a decline in younger generations also concords with the cohort hypothesis.
Social class
Analysis of changes in mortality by social class over the last three censuses again shows upward age-shifts which suggest that each generation is carrying forward its own particular risk. At each successive census, a more or less regular pattern of mortality recurred in age-groups which were older by the interval which had elapsed between the censuses.
Statistics relate only to males, and are first available for the period of the 1921 census.18 From 1921 to 1923 death-rates from gastric ulcer showed a social-class gradient increasing from the higher to the lower classes up to the age of 55; this gradient flattened between 55 and 70, and was reversed over the age of 70. A decade later, in the period 193032, the gradient increasing from higher to lower classes was apparent up to age 65 and then reversedi.e. ten years older than at the previous census. In the period 194952 the gradient increasing from higher to lower classes persisted up to the age of 70 before it flattened (Figure 3a). Although death-rates in old age must be interpreted with caution, the trend fits the expectation.
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One may perhaps infer that morbidity shows similar social-class trends, by comparing the survey of men in industry after the war with a recent survey in York.12,19 No significant social-class gradient was found among the industrial workers (most of whom were under 65), whereas a decade later a gradient rising towards the lower classes was apparent in York.
Thus the recession of the wave of duodenal ulcers seems to have begun in young men of the higher social classes. Perhaps also men of the higher social classes were first affected when the incidence of peptic ulcer began to rise early this century; but social-class statistics do not go back far enough to support this inference.
We have not here considered the complicating effects of social mobility on social-class patterns, but for the purpose of analysis have tended to treat social classes as static categories.
Discussion
The fluctuations in peptic-ulcer syndromes seem to vary with the experience of cohorts, and this makes interpretations other than real changes in incidencefor example changes in diagnostic practiceunlikely. Nevertheless, they must be considered.
The effects of greater accuracy in diagnosis and in certifications would be expected to run counter to the current decline in peptic-ulcer death-rates. The statistical distortions caused by fashions in diagnosis, which like other fashions show both secular trends and social mobility, can also be discounted, for changes in incidence seem to have preceded changes in medical opinion. Thus in the present instance it is the fashionable view that the disease is increasing, although the rates are falling. In a second instance, duodenal ulcer was held to be a disease of young men until recently, when Doll et al. (1951) showed it to be common among middle-aged and elderly men. The fashionable clinical view probably arose from the experience of physicians earlier in the century, for the young patients of these physicians later formed the middle-aged cohorts observed by Doll et al. Clinical impression again lagged behind reality.
The social-class gradient now apparent at older ages might be ascribed to unequal and selective survival between classes. Sufferers from peptic ulcer in the lower social classes might have died at young ages, leaving survivors of the higher classes to raise the mortality rates in old age. However, the evidence presented here shows that those cohorts who now have high death-rates also had high death-rates in youth.
Uneven distribution of treatment in various age and class groups seems not to account for their unequal death-rates. The high mortality among the older age-groups in the higher social classes is contrary to what would be expected, unless the treatment were harmful, for all studies show that the higher social classes make more use of medical services. The recent popularity of partial gastrectomy is unlikely to be an important cause of the decline in perforations. Cures by gastrectomy could hardly account for the steady rise in the mean age of patients admitted to hospital for perforations, a rise which in Scotland began in 1924. Furthermore, no known treatment seems to be so effective that it could have produced the fall in morbidity suggested by recent statistics.
None of these alternative explanations, therefore, is in accord with all the facts. Indeed, the existence of a cohort pattern is in itself strong evidence that observed changes do not arise from changes in diagnostic practice or treatment. In addition, the prediction that the disease is on the decline, and that the pattern is consistent with a cohort phenomenon, has survived its first test. It was put forward as the tentative explanation for the trend of death-rates up to 1955.20 Since then statistics for the period 195659 have been published by the General Register Office.3 The trend of these statistics is consistent with what was predicted in practically every age and sex group for both gastric and duodenal ulcer.
Aetiology
On this analysis duodenal ulcer is on the decline and cannot be regarded simply as a disease of civilization, in the sense that it is caused mainly by stresses common to industrial society; for these might be expected to increase or at least to continue as our society grows more complex, and as a greater proportion of the population is caught up in urban modes of life. However, it could be a disease of an early phase of urbanization. In the most recent times urban stresses may have been outweighed by other consequences of industrialization, such as the abolition of gross poverty and the greater social security in modern Britain. Moreover, changes in the host must also be considered as a cause of fluctuations in disease. Large sections of the population may by now have learned to adapt to the demands of industrial society, so that these are felt as less stressful than before.
On the other hand, the cohort phenomenon might reflect upheavals which have had an uneven impact on past generations. The timing of the first world war, and the unemployment of the 1930s, roughly fit the fluctuations, and the cohorts with the highest peptic-ulcer death-rates were also the chief victims of the first world war. The immediate effects of war are evident in the rise in perforations and deaths from peptic ulcer which followed air-raids and the stress of war.5,18,21,22 Perhaps in a chronic condition such as this acute events might precipitate prolonged effects.
We have begun to explore possibilities of this kind in populations with different experiences, as for example in Sweden and the United States. Analysis by cohorts may assist us in separating the contribution of past from present experiences in the configuration of this chronic disease.
Summary
Peptic-ulcer death-rates in England and Wales reached a peak in the 1950s and have since begun to decline; signs of a decline can also be found in sickness-rates. These fluctuations are interpreted as a cohort phenomenon. The generations born in the last quarter of the 19th century seem to have been exposed to the maximum risk, and they carried this risk throughout adult life. The wave of gastric ulcers began earlier, and receded earlier, than the wave of duodenal ulcers.
Ideas on aetiology are considered in the light of this interpretation.
We wish to thank Mrs Ann Pendred for her great help with abstracting data and drawing graphs. We are indebted to the department of medical illustration, Manchester Royal Infirmary, and Mrs A Fish for help with illustrations, and to the General Register Office who supplied estimated populations from 1838.
We are grateful to Dr AM Adelstein and our other colleagues in the department of social and preventive medicine, Manchester University, for advice and criticism.
Notes
* Read at the annual scientific meeting of the Society for Social Medicine, September, 1961. Reprinted with permission of The Lancet. Susser M, Stein Z. Civilisation and peptic ulcer. Lancet 1962;20 January:11519.
Gastric ulcer has been recorded by the Registrar General as a cause of death annually since 1901. Ulceration of the Intestines was recorded in 1900, not in 1901, 1902, 1903, 1904 but again from 1905 to 1910, and in our graphs this has been classed for convenience as duodenal ulcer. The term duodenal ulcer has been recorded regularly from 1911.
Part I. HM Stationery Office. Decennial Supplements England and Wales, 1921, 1931, 1951.
Part II. Occupational Mortality. HM Stationery Office.
Doll, R. (1961) Personal communication.
References
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2 Jones FA. (1947) Br Med J. ii, 441.
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