a University of Bristol, Department of Social Medicine, Bristol, UK.
b Columbia University, Department of Epidemiology, New York, USA.
In this issue of the International Journal of Epidemiology we highlight the contributions of two pioneering self-taught epidemiologists, Zena Stein and Mervyn Susser. Their joint paper Civilization and Peptic Ulcer, originally published in the Lancet in 1962, appears as one of our series of reprints of important epidemiological papers, along with several commentaries. These include a reflection, 40 years on, by the original authors. A companion series of papers originated in an international symposium held by the Mailman School of Public Health of Columbia University, New York, to mark the 80th years of both Zena and Mervyn. The event ended in a manner perhaps unusual for such an occasion: it was closed by Ahmed Kathrada, a friend of Zena and Mervyn, who was incarcerated with Nelson Mandela on Robben Island during the struggle against apartheid in South Africa. He read out a letter from Nelson Mandela to mark the occasion (Box 1).
Box 1 Letter from Nelson Mandela Dear Zena and Mervyn As someone who became an octogenarian three years ago, I have great pleasure in saying Welcome to the Club'. Over the years, especially when we were in prison, we managed to get trickles of information about you. It was always heartening to know that, albeit under different circumstances and many miles from home, your commitments and active contribution to struggle for democracy remained undiminished. Although we are divided by a great distance today, please know that our thoughts and best wishes are with you, and with all the friends who are joining you in the celebration. Hearty congratulations! Nelson Mandela
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The interlocked careers of Zena and Mervyn have been described elsewhere,1 as well as in the present collection.2 The range of their work in epidemiology and public health can be appreciated from the bibliographies which we have made available on the web (http://www.ije.oupjournals.org). Therefore here we will just give a brief account of their continuing contributions to epidemiology and public health.
For both Zena and Mervyn their work in epidemiology and public health started in South Africa and has continued to have a strong attachment to that country. Their initial driving motivation was to contribute to the health and medical care of non-whites' in apartheid South Africa in the early 1950s. This majority population was virtually ignored in medical curricula at the time, so the task meant striking out with a small group of colleagues to direct a township' clinic, in Alexandra, Johannesburg. Although they began with no knowledge of epidemiology, the effort naturally led them to carry out one of the first studies of community health in the developing world, published in the Lancet in 1955 as Medical Care in an African Township'.3 It was during this period that they developed ties with Ahmed Kathrada, Walter Sisulu, Joe Slovo and Nelson Mandela, among many others, in the anti-apartheid movement. The efforts made by them and others such as Sidney Kark4 (a mentor) to address the health of the community as a whole is of more than historic importance; if anything, it may be even more germane today than it was then. Even as the AIDS epidemic brings catastrophe to South Africaas outlined in the present collection5medical training in that country still fails to give any centrality to the care and prevention of HIV/AIDS. Zena and Mervyn are once again in the centre of the melee, supporting those in South Africa who want to bring about change.
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Due to political difficulties in South Africa in 1955, they settled in England for the next decade. Taking positions at Manchester University, they took up research on what are now called developmental disabilities. Their many early contributions to this field are exemplified by studies showing the influence of the social environment on the subsequent development of children with marginally low IQ.6 But this was only one of many directions established. The peptic ulcer paper was written during this period.7 In his related post as Medical Officer for Mental Health in Salford, Mervyn established a psychiatric registry and used it for the first study of the incidence of specific mental disorders in a large urban population.8 Both Zena and Mervyn were interested in issues related to social class, with Zena working with Fraser Brockington on educational attainment and social background,9 and Mervyn producing his first detailed review of social class differences in health.10 Then, at Zena's urging, Mervyn joined with William Watson, an anthropologist, to write the first edition of the influential textbook Sociology in Medicine,11 demonstrating how society and health are interwoven across every stage of the lifecycle. With the current enthusiasm for lifecourse epidemiology'12 it is salutary to read, in an earlier paper on peptic ulcer than the one we are reprinting in this issue, that the process of ageing is not only inherently determined; every organism incorporates its life experience from birth onwards'.13 It was fitting that Mervyn wrote the forward to the first textbook of lifecourse epidemiology.12
When Zena and Mervyn moved to the US in 1965, they were recruited by the School of Public Health at Columbia University to lead the Division of Epidemiology. Mervyn, appointed chairman but with no formal training in the discipline, was faced with the challenge of articulating to a sceptical faculty the need to make a transition to the chronic disease' era of epidemiology, while at the same time, retaining the insights about society and health described in Sociology in Medicine. The result was a series of lectures later formalized in Causal Thinking in the Health Sciences.14 The book was widely read; the Annual Review of Public Health included a critique and commemoration of the book 25 years later.15 At the time, the book was mainly recognized for its clean distillation of the concepts needed for understanding and investigating risk factors. A contemporary reader will see several particular features which distinguish it (together with another pioneering text, Jerry Morris' Uses of Epidemiology16,17). First, the distinction between distant and immediate causes was made, with the determining role of the former rendering them the appropriate target for interventions that could have major public health significance. Second, an ecological view of epidemiology was advanced and the importance of considering different levels of determination of diseaselater developed with Ezra Susser and others18,19was already apparent. Finally and perhaps most unusuallythe need to consider and critique why we, as epidemiologists, think the way we do, was advocated. Our frames of reference, it is suggested, can constrain our imaginations and lead us astray. This insight has relevance for the peptic ulcer paper and commentaries we are printing in this issue (Box 2).
Box 2 Frames of reference In Causal Thinking in the Health Sciences14 the importance of frames of reference in the organization of causal models in epidemiology was emphasized. To illustrate this, two in-depth examples were given, one of schistosomiasis as illustrative of transmissible disease, and one of duodenal ulcer as illustrative of a non-transmissible disease. In their innovative work on peptic ulceran example of which is reprinted in this issue of the International Journal of Epidemiology7Mervyn and Zena had developed a counterpoint to the prevailing view of peptic ulcer as a protypical disease of civilization'. They interpreted the intriguing birth cohort patterns of peptic ulcer as compatible with exposure of the older age groups to poor environmental conditions in their childhood or young adulthood; peptic ulcer could be a disease of an early phase of urbanization'. The British birth cohort with the highest risk of peptic ulcer had lived at different stages of their lives through the stressful periods of the First World War, the depression and high unemployment in the 1930s and then the Second World War. Nonetheless, Mervyn and Zena adhered to the almost universally held view that peptic ulcer was a non-infectious diseaseand thus within the non-transmissible disease frame of reference' Mervyn developed for duodenal ulcer in his book.14 Similarly, Jerry Morriswho had also carried out innovative work on peptic ulcer20 (and whose textbook Uses of Epidemiology16 was much concerned with the increasing burden of peptic ulcer, along with coronary heart disease and lung cancer)applied chronic disease models to considerations of the aetiology of peptic ulcer. Indeed, in the preface to Uses of Epidemiology he stated that a more accurate title would be "Some Uses of Epidemiology in the Study of Non-communicable Diseases"'.16 As several of the commentaries in this issue make clear,2123 over the past 20 years we have learned that a major determinant of peptic ulcer is Helicobacter pylori infection; this is an infection generally acquired in childhood which would be related to the poor environmental conditions accompanying early industrialization, which Mervyn and Zena discussed in their 1962 paper.7 For epidemiologistsincluding Mervyn, Zena and Jerry Morrisworking with a non-communicable disease frame of reference, the search for this determiningand treatablecause of peptic ulcer was perhaps constrained by infectious agents being ruled out of consideration. The importance of critically evaluating frames of referenceas, innovatively advocated in Causal Thinking in the Health Sciences14is well illustrated by this example, and is surely as relevant today as it was in previous periods.
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Zena and Mervyn's subsequent contributions to epidemiology and public health are numerous and wide-ranging; so much so that we cannot do them justice in a short commentary. Among the areas they innovated were social epidemiology, discussed above, and genetic epidemiology,24 exemplified by their investigations of genetic causes of spontaneous abortions.25,26 We will discuss only their series of studies on prenatal nutrition and cognitive development, and their ongoing research on HIV/ AIDS in Africa. These two are chosen because they illustrate well how Zena and Mervyn combined scientific rigor and social commitment in the way they practised epidemiology.
Their interest in prenatal nutrition and cognitive development spans many decades, dating back to the 1960s, and continuing with current research. Undoubtedly, however, one study stands out above the others: the investigation of the consequences of the Dutch Hunger Winter of 19441945.27 Many observational studies28,29 and reviews of the literature suggested that low birthweight was associated with impaired cognitive function and intelligence. They recognized that the problems of attributing causation in this area are immense, however, and therefore subjected it to a much more rigorous test within a quasi-experiment, made possible by a historic tragedy, the acute but severe famine in Holland precipitated by a Nazi blockade. The design compared cognitive outcomes in birth cohorts exposed and unexposed to the famine at various stages of prenatal life. The investigation found that in a developed society there was no evidence of an effect of prenatal famine on IQ at age 18. This result refuted the favoured hypothesis of the time (which they had also held), supported by prior observational data,28,29 and it drew heavy fire, but the result was confirmed as well as elaborated by a randomized trial of prenatal nutritional supplementation which they carried out with David Rush in Harlem.30 The trial found prenatal protein supplementation to have only modest beneficial effects on cognition (e.g. on infants' habituation), and these were counterbalanced by an unexpected adverse effect on preterm birth. The original controversy and disappointment about the main finding of the Dutch famine study are an important part of the history of this field, though perhaps unfortunately they have now been overshadowed by important results that later emerged, among which are the early clues that prenatal nutrition is related to neural tube defects,27 and the sharp association of prenatal famine with schizophrenia.31 It is salutary to remember the original finding from the Dutch Hunger Winter study, particularly when there has been considerable enthusiasm generated by largely observational findings that maternal nutrition, birthweight and exposures during infancy and childhood are related to chronic diseases in adulthood.12,32
By contrast, Zena and Mervyn's work on HIV/AIDS is a relatively recent development. But for that very reason, it is exemplary for young epidemiologists, in a different way. New York was an epicentre of the epidemic in its early phase in the 1980s, and they were among a small number of well-established chronic disease' epidemiologists ready to join the effort to combat it, relearning and retooling as required by the evolving public health crisis. A few years thereafter, the pattern of the epidemic shifted, and it became clear that HIV/AIDS was poised to bring catastrophe to South Africa within a decade. Zena and Mervyn did all they could to alert the African National Congress and others of the impending disaster, organizing a conference in Maputo with health activists of the region, including some of the nascent shadow government. In the context of this dramatic and dangerous period of transition to democracy, however, all warnings of a future health event tended to be drowned out. Not to be deterred, they continued the effort, and Zena initiated a (still flourishing) training programme in the epidemiology of HIV/AIDS, which brought many South Africans to New York City to obtain epidemiology degrees at Columbia University, School of Public Health; virtually all of them returning to South Africa. Zena was one of the first and most effective advocates for promoting women's condoms, and for developing and testing new microbiocides and other methods that women control to reduce heterosexual transmission risk of HIV.33 Mervyn as editor of the American Journal of Public Health brought these issues to the fore. Their work continues, with many offshoots, now evident in a developing partnership between the Nelson Mandela School of Medicine in Durban and the Mailman School of Public Health in New York.
Epidemiology is ultimately a science that provides the basis for public health action, and that is no less the case in the era of molecular and genetic epidemiology.34 Zena and Mervyn's contribution has been in showing that only the strongest possible evidencecombined with the strongest possible commitment to the necessary social and environmental changes that the evidence indicates are requiredprovides the basis for effective public health policy and practice. We look forward to their continued contributions in this regard.
References
1 Neugebauer R, Paneth N. Epidemiology and the wider world: celebrating Zena Stein and Mervyn Susser. Paediatr Perinat Epidemiol 1992;6:12232.[Medline]
2
Oppenheimer GM, Rosner D. Two lives, three legs, one journey: a retrospective appreciation of Zena Stein and Mervyn Susser. Int J Epidemiol 2002;31:4953.
3 Susser M, Stein Z, Cormack M, Hathorn M. Medical care in a South African township. Lancet 1955;i:91215.
4 Susser M. A South African odyssey in community health: a memoir of the impact of the teachings of Sidney Kark. Am J Public Health 1993;83:79293.[ISI][Medline]
5
Karim S. The evolving HIV epidemic in South Africa. Int J Epidemiol 2002;31:3739.
6 Stein Z, Susser M. Mental retardation: a cultural syndrome. Proc Conf Sci Study Ment Def (London) 1962, pp.17478.
7
Susser M, Stein Z. Civilization and peptic ulcer. Reprinted Int J Epidemiol 2002;31:1317.
8 Susser M. Community Psychiatry: Epidemiologic and Social Themes. New York: Random House, 1968.
9 Brockington F, Stein ZA. Admission, achievement and social class. Universities Quarterly 1963;16:5273.
10 Susser M. Social medicine in Britain: studies of social class. In: Welford AT, Argyle M, Glass DV, Morris JN (eds). Society: Problems and Methods of Study. London: Routledge and Kegan, 1962, pp.12757.
11 Susser MW, Watson W, Hopper K. Sociology in Medicine. New York: Oxford University Press, 1985.
12 Kuh D, Ben-Shlomo Y. A Lifecourse Approach to Chronic Disease Epidemiology. Oxford: Oxford University Press, 1997.
13 Susser M. Environmental factors and peptic ulcer. Practitioner 1961;186:30211.[ISI]
14 Susser M. Causal Thinking in the Health Sciences. Concepts and Strategies in Epidemiology. New York: Oxford University Press, 1973.
15 Kaufman JS, Poole C. Looking back on Causal Thinking in the Health Sciences. Annu Rev Public Health 2000;21:119.[CrossRef][ISI][Medline]
16 Morris JN. Uses of Epidemiology. Edinburgh: Livingstone, 1957 (and subsequent editions in 1964 and 1975).
17
Davey Smith G. The uses of Uses of Epidemiology'. Int J Epidemiol 2001;30:114655.
18 Susser M, Susser E. Choosing a future for Epidemiology: I. Eras and Paradigms. II. From Black Boxes to Chinese Boxes. Am J Public Health 1996;86:66878.[Abstract]
19 Schwartz S, Susser E, Susser M. A future for Epidemiology? Annu Rev Public Health 1999;20:1533.[CrossRef][ISI][Medline]
20 Morris JN, Titmuss RM. Epidemiology of peptic ulcer: vital statistics. Lancet 1944;ii:84145.
21
Marshall B. Helicobacter as the environmental factor' in Susser and Stein's cohort theory in peptic ulcer disease. Int J Epidemiol 2002;31:2122.
22
Sonnenberg A, Cucino C, Bauerfeind P. The unresolved mystery of birth-cohort phenomena in gastroenterology. Int J Epidemiol 2002, 31:2326.
23
Susser M, Stein Z. Civilization and peptic ulcer 40 years on. Int J Epidemiol 2002;31:1821.
24 Owens KN, Harvey-Blankenship M, King M-C. Genomic sequencing in the service of human rights. Int J Epidemiol 2002;31:5458.
25 Stein ZA, Susser MW, Warburton D, Wittes J, Kline J. Spontaneous abortion as a screening device: the effect of fetal survival on the incidence of birth defects. Am J Epidemiol 1975;102:27590.[Abstract]
26 Stein Z. A woman's age: childbearing and child rearing. Am J Epidemiol 1985;121:32742.[ISI][Medline]
27 Stein Z, Susser M, Saenger G, Marolla F. Famine and Human Development. New York: Oxford University Press, 1975.
28 Asher C, Roberts JAF. A study of birthweight and intelligence. Br J Prev Soc Med 1949;3:5668.
29 Barker DJP. Low intelligence: its relation to length of gestation and rate of foetal growth. Br J Prev Soc Med 1966;20:5866.[ISI][Medline]
30 Rush D, Stein Z, Susser M. Diet in Pregnancy: A Randomized Controlled Trial of Nutritional Supplements. New York: Alan R Liss, Inc., 1980.
31 Susser E, Hoek HW, Brown A. Neurodevelopmental disorders after prenatal famine: the story of the Dutch Famine Study. Am J Epidemiol 1947;3:21316.
32 Barker DJP. Mothers, Babies and Health in Later Life. Edinburgh: Churchill Livingston, 1998.
33 Stein Z. HIV prevention: the need for methods women can use. Am J Public Health 1990;80:46062.[Abstract]
34 Clayton D, McKeigue PM. Epidemiological methods for studying genes and environmental factors in complex diseases. Lancet 2001;358:135660.[CrossRef][ISI][Medline]