BRITISH MEDICAL JOURNAL
14 AUGUST 1976
from its dependence on the Treasury-then the balance of the arguments may have tipped in favour of introducing such an experiment. The case against student loans was firmly put by the Robbins Committee on Higher Education4 in 1963, which pointed out that their effect might be to discourage children from poorer homes from going to a university. Furthermore, the committee argued "either British parents would be strengthened in their age-long disinclination to consider their daughters to be as deserving of higher education as their sons, or the eligibility for marriage of the more educated would be diminished by the addition to their charms of what would in effect be a negative dowry." However, the Robbins report also conceded that as time went on there might be a case for some experiment. Arguments for such an experiment in student loans have been strengthened since the Robbins report appeared by evidence that many of the disadvantages can in fact be overcome. In particular, schemes have been designed in the United States5 which make the repayment of loans contingent on earnings: that is, the repayments are calculated as a fixed percentage of income. Thus, for example, a woman doctor would repay the loan only while she was in employment; if she dropped out of the labour force temporarily, the payments would stop. So the problem of a negative dowry (or of a millstone of debt hanging round the neck of every newfledged graduate) seems to be avoidable. There are special problems in the medical profession. One result of introducing a loan system, it may be argued, might be to increase still further the attractions of emigration, since it would be almost impossible, administratively and legally, to enforce debt repayment from abroad. As against this, it could be maintained that a loan system would permit new incentives to be introduced to persuade doctors to move into unpopular specialties or underdoctored parts of the country. Every year's service might count for double so far as debt repayments were concerned. Whether such a radical solution would be acceptable to the medical profession is another matter. Still, given the pressures on all public services, it seems worth investigating the possibilities inherent in what until now have been regarded as unthinkable policy options. The alternative-of making still further economies-may be more unthinkable still. I
British Medical Journal,
1974, 2, 458.
2
Public Expenditure
3
Klein, R, Buxton, M, and Outram, Q, Social Policy and Public Expenditure, 1976: Constraints and Choices. London, Centre for Studies in Social Policy, 1976. Committee on Higher Education Report, Cmnd 2154, London, HMSO,
4
to 1970-80, Cmnd 6393. London, HMSO, 1976.
1963.
Challoner, D R, New England Journal of Medicine, 1974, 290, 160.
Hard water story: no recommendations In 1960 Schroeder showed that male deaths from cardiovascular diseases in 163 cities in the United States were less common where the concentrations of calcium and magnesium in drinking-water were high.1 2 Within a few days of receiving these results, Morris and his co-workers at the Medical Research Council Social Medicine Unit in London used data already in their hands to confirm that this negative correlation
389
also existed in England and Wales, at least with respect to total water hardness and calcium concentration.3 In 1962 they said :4 "It is intriguing that further work confirms the existence of a water factor in cardiovascular disease of middle age and early old age, though no hypothesis regarding its nature or action is yet forthcoming." In general terms that statement remains as true today as 14 years ago. Siegfried Heyden has recently reviewed5 the water story, assessed published work, and raised valid questions about whether it is wise to offer the public advice about their tapwater. The evidence that hard water is protective or soft water harmful is not compelling. True, mortality studies in the USA,' 2 England and Wales,3 6 and Canada7 have shown a negative association between hardness and cardiovascular mortality, but the features associated with mortality have differed among studies, and other investigations have failed to show any association. For example, in North Carolina (where mortality from cardiovascular and particularly cerebrovascular causes is high even for the United States) the lowest rates were found in the areas with the softest water.8 Neither were significant correlations found between hardness and cardiovascular mortality in rural counties of Oklahoma, in which geographic, environmental, and social variables would have been more uniform than in the larger national studies.9 Nor was a relation found in three communities in Los Angeles which were similar for age, sex, race, income, socioeconomic status, and stability but different in water hardness.10 In a careful study in Maryland no difference was found between the hardness of the home tap-water of men aged 45-64 who had died from arteriosclerotic or degenerative heart disease and that of controls." In studies in Ireland'2 and England and Wales,13 1 too, negative or inconsistent results have been obtained. Since there is no attractive hypothesis which could unite all these diverse findings, some epidemiologists have thought that other factors might be related both to water hardness and to cardiovascular mortality and that water hardness might be merely an index. Gardner, Crawford, and Morris'5 investigated the independent associations between cardiovascular mortality and a social factor score, a measure of air pollution, latitude, long period rainfall, and water calcium. Latitude and rainfall as well as water calcium were all independently associated with cardiovascular mortality. A climatic factor was also found in an analysis of data from 116 metropolitan areas in the USA, for which a "comfort index" was derived from temperature and relative humidity.'6 This factor was a more important correlate of mortality than the water variables. The authors suggested that thermal stress occurring in both hot and humid or cold and damp periods of the year might have a direct effect on the cardiovascular system. Because of the strong inverse correlation between rainfall and water hardness,'5 data from South Wales'4 and England and Wales 14'17 were analysed to determine how important long- and short-term climatic factors were as correlates of mortality from ischaemic heart disease and whether they would account for the apparent association of mortality with water hardness. The results indicated that water calcium owed its association with heart disease almost entirely to its own association with temperature and rainfall. The possibility that the relation between temperature and mortality from ischaemic heart disease is causal has been discussed recently.'8 This fascinating story is not tied up by any means. Reports of the association continue to appear,'9 20 and to be explained away.21 Nevertheless, despite all these inconsistencies in the evidence two official publications have made recommenda-
390
BRITISH MEDICAL JOURNAL
tions. One22 states that: ". . . any propoOals for softening the water supply in any part of the country [UK] should be considered in the light of knowledge about the observed positive relationship between the death rate from ischaemic heart disease and the softness of the local water supply." The second23 states: "Where domestic water softeners are used, it might be prudent for drinking-water to be taken from the mains supply." Both are counsels for inaction, which is the most our present knowledge should allow. Schroeder, H A, J'ournal of the American Medical Association, 1960, 172, 1902. 2Schroeder, H A, Journal of Chronic Diseases, 1960, 12, 568. 3 Morris, J N, Crawford, M D, and Heady, J A, Lancet, 1961, 1, 860. 4 Morris, J N, Crawford, M D, and Heady, J A, Lancet, 1962, 2, 506. Heyden, S, Journal of Chronic Diseases, 1976, 29, 149. 6 Crawford, M D, Gardner, M J, and Morris, J N, Lancet, 1968, 1, 827. 7Anderson, T W, Le Riche, W H, and Mackay, J S, New England J7ournal of Medicine, 1969, 280, 805. 8 Tyroler, H A, in The Community as an Epidemiological Laboratory, eds I I Kessler and M L Levin, p 100. Baltimore, Johns Hopkins, 1970. 9 Lindeman, R D, and Assenzo, J R, American Journal of Public Health, 1964, 54, 1071. '0 Allwright, S P A, et al, Lancet, 1974, 2, 860. 11 Comstock, G W, American Journal of Epidemiology, 1971, 94, 1. 12 Mulcahy, R, Journal of the Irish Medical Association, 1964, 55, 17. 13 Elwood, P C, Abernethy, M, and Morton, M, Lancet, 1974, 2, 1470. 14 Roberts, C J, and Lloyd, S, Lancet, 1972, 1, 1091. 15 Gardner, M J, Crawford, M D, and Morris, J N, British Journal of Preventive and Social Medicine, 1969, 23, 133. 16 Dudley, E F, Beldin, R A, and Johnson, B C, Journal of Chronic Diseases, 1969, 22, 25. 17 West, R R, Lloyd, S, and Roberts, C J, British Journal of Preventive and Social Medicine, 1973, 27, 36. 18 West, R R, and Lowe, C R, International3Journal of Epidemiology, 1976, 5, 195. 19 Anderson, T W, et al, Canadian Medical Association Journal, 1975, 113, 199. 20 Chipperfield, B, et al, Lancet, 1976, 1, 121. 21 Campos, A T, Lancet, 1976, 1, 1244. 22 DHSS, Report on Health and Social Subjects 7, Diet and Coronary Heart Disease. London, HMSO, 1974. 23 Report of a Joint Working Party of the Royal College of Physicians of London and the British Cardiac Society, Journal of the Royal College of Physicians, 1976, 10, 213; Royal College of Physicians and British Cardiac Society, British Medical3Journal, 1976, 1, 881.
pandemic Is the cholera ; waning? *D
The current pandemic of cholera, if not on the decline, may be at least becoming stabilised.' In 1975 the number of countries notifying cholera was the smallest since 1970. The disease extended to only one new country in Africa and only one in Asia. The trend seems generally downwards. In 1970 cholera was reported by 36 countries with a total of 155 555 cases. In 1975 the score was 29 countries and 87 475 cases. The drop in numbers of countries and cases was most notable in Africa. On the whole the same countries remained infected in Asia. In Europe cholera continued in limited "epidemic" form in Portugal and there were some possibly "endemic" cases in France and Spain. Cases were imported into Britain and Italy. This fall is encouraging, especially in view of the improvement in national and international surveillance which has brought some sort of reality to the figures quoted. Earlier in the pandemic reported outbrtaks sometimes led to drastic long-term and financially damaging measures by neighbouring countries, including restriction of imports and closure of ports and airports; and this resulted in resistance to reporting the presence of the disease and so made world figures unrealistic. The introduction of International Health Regulations in 1969 in place of the more rigid International Sanitary Regula-
14 AUGUST 1976
tions seems to have reduced the fear of unwarranted sanctions.2
3
The current pandemic has resulted from the spread of the El Tor vibrio, discovered in 1906 in a village of the same name in the Sinai Peninsula. For many years regarded as a maverick, and not included in the WHO list of choleraproducing vibrios, the organism eventually reappeared in 1938 as the cause of a mild cholera-like disease in Sulawesi, and cases were reported in Java and Singapore during the second world war. A decade later the new vibrio spread rapidly throughout South-east Asia. In 1961 there were over 10 000 cases, many severe, in the Philippines. By 1963 Thailand, the Khmer Republic, Vietnam, Hong Kong, Burma, India, and both Pakistans became affected. In 1966 the disease appeared in Iraq and Syria and then spread westward, reaching eastern Europe, North Africa, and Africa south of the Sahara (probably for the first time in history). Imported cases began to appear in western Europe, including Britain, and sporadic outbreaks occurred in other countries, especially Portugal. Except in Bangladesh the El Tor organism now occupies the former endemic areas of the classical vibrios, which have otherwise practically disappeared. The spread of the vibrio has been encouraged by the increasing ease and frequency of contacts in infected areas. For the initial transfer over long distances the aeroplane has been the major agent. Over short distances the ship has also played its part, as in the (presumed) transfer from Sulawesi to Java. Once established, the infection has spread within a country and to its neighbours through movements of people across uncontrolled terrain, national borders, and along rivers and coastal areas by fisherman, as in West Africa. The establishment of the disease depends on the coexistence of an insanitary environment and a population ignorant of hygiene. These two factors are common to the spread of all vibrios, but the El Tor organism has certain advantages over its rivals. Once it reaches receptive insanitary areas it tends to remain in them and may well stay there until sanitation improves sufficiently; and so new endemic areas are set up. The new vibrio is more persistent in the human body than the others and is commonly excreted in the faeces for two to three weeks after infection, whether or not accompanied by symptoms. There are also occasional chronic carriers, who are not found with the classical infections. Clinical effects may be as severe as in any other form of cholera, or they may be mild or absent. However, the patient, the convalescent, and the silent case all excrete the organism. Modern methods of treatment are excellent if offered early, but in large areas of the developing world, where cholera is most frequent, treatment is often unavailable. Where poverty, inaccessibility, and ignorance reign, the death rate is high. In 1976 cholera is still very much with us, spread across the world, except, most remarkably, in the Americas-a possible pointer to control elsewhere. In contrast to our control of smallpox we have not yet got the weapons to eradicate cholera. We certainly cannot rely on the present inefficient vaccine. In the long run-and it may be a very long run-the final answer must be to make receptive areas ununreceptive by transformation of their sanitation. This is a problem for medical and health education and the provision and proper use of national and international funds. IWorld Health Organisation, Weekly Epidemiological Record, 1976, 51, 137. 2 World Health Organisation, International Health Regulations, 1969, 2nd edn. Geneva, World Health Organisation, 1974. 3 World Health Organisation, International Sanitary Regulations, 1951, annotated ed. Geneva, World Health Organisation, 1957.
14 AUGUST 1976
from its dependence on the Treasury-then the balance of the arguments may have tipped in favour of introducing such an experiment. The case against student loans was firmly put by the Robbins Committee on Higher Education4 in 1963, which pointed out that their effect might be to discourage children from poorer homes from going to a university. Furthermore, the committee argued "either British parents would be strengthened in their age-long disinclination to consider their daughters to be as deserving of higher education as their sons, or the eligibility for marriage of the more educated would be diminished by the addition to their charms of what would in effect be a negative dowry." However, the Robbins report also conceded that as time went on there might be a case for some experiment. Arguments for such an experiment in student loans have been strengthened since the Robbins report appeared by evidence that many of the disadvantages can in fact be overcome. In particular, schemes have been designed in the United States5 which make the repayment of loans contingent on earnings: that is, the repayments are calculated as a fixed percentage of income. Thus, for example, a woman doctor would repay the loan only while she was in employment; if she dropped out of the labour force temporarily, the payments would stop. So the problem of a negative dowry (or of a millstone of debt hanging round the neck of every newfledged graduate) seems to be avoidable. There are special problems in the medical profession. One result of introducing a loan system, it may be argued, might be to increase still further the attractions of emigration, since it would be almost impossible, administratively and legally, to enforce debt repayment from abroad. As against this, it could be maintained that a loan system would permit new incentives to be introduced to persuade doctors to move into unpopular specialties or underdoctored parts of the country. Every year's service might count for double so far as debt repayments were concerned. Whether such a radical solution would be acceptable to the medical profession is another matter. Still, given the pressures on all public services, it seems worth investigating the possibilities inherent in what until now have been regarded as unthinkable policy options. The alternative-of making still further economies-may be more unthinkable still. I
British Medical Journal,
1974, 2, 458.
2
Public Expenditure
3
Klein, R, Buxton, M, and Outram, Q, Social Policy and Public Expenditure, 1976: Constraints and Choices. London, Centre for Studies in Social Policy, 1976. Committee on Higher Education Report, Cmnd 2154, London, HMSO,
4
to 1970-80, Cmnd 6393. London, HMSO, 1976.
1963.
Challoner, D R, New England Journal of Medicine, 1974, 290, 160.
Hard water story: no recommendations In 1960 Schroeder showed that male deaths from cardiovascular diseases in 163 cities in the United States were less common where the concentrations of calcium and magnesium in drinking-water were high.1 2 Within a few days of receiving these results, Morris and his co-workers at the Medical Research Council Social Medicine Unit in London used data already in their hands to confirm that this negative correlation
389
also existed in England and Wales, at least with respect to total water hardness and calcium concentration.3 In 1962 they said :4 "It is intriguing that further work confirms the existence of a water factor in cardiovascular disease of middle age and early old age, though no hypothesis regarding its nature or action is yet forthcoming." In general terms that statement remains as true today as 14 years ago. Siegfried Heyden has recently reviewed5 the water story, assessed published work, and raised valid questions about whether it is wise to offer the public advice about their tapwater. The evidence that hard water is protective or soft water harmful is not compelling. True, mortality studies in the USA,' 2 England and Wales,3 6 and Canada7 have shown a negative association between hardness and cardiovascular mortality, but the features associated with mortality have differed among studies, and other investigations have failed to show any association. For example, in North Carolina (where mortality from cardiovascular and particularly cerebrovascular causes is high even for the United States) the lowest rates were found in the areas with the softest water.8 Neither were significant correlations found between hardness and cardiovascular mortality in rural counties of Oklahoma, in which geographic, environmental, and social variables would have been more uniform than in the larger national studies.9 Nor was a relation found in three communities in Los Angeles which were similar for age, sex, race, income, socioeconomic status, and stability but different in water hardness.10 In a careful study in Maryland no difference was found between the hardness of the home tap-water of men aged 45-64 who had died from arteriosclerotic or degenerative heart disease and that of controls." In studies in Ireland'2 and England and Wales,13 1 too, negative or inconsistent results have been obtained. Since there is no attractive hypothesis which could unite all these diverse findings, some epidemiologists have thought that other factors might be related both to water hardness and to cardiovascular mortality and that water hardness might be merely an index. Gardner, Crawford, and Morris'5 investigated the independent associations between cardiovascular mortality and a social factor score, a measure of air pollution, latitude, long period rainfall, and water calcium. Latitude and rainfall as well as water calcium were all independently associated with cardiovascular mortality. A climatic factor was also found in an analysis of data from 116 metropolitan areas in the USA, for which a "comfort index" was derived from temperature and relative humidity.'6 This factor was a more important correlate of mortality than the water variables. The authors suggested that thermal stress occurring in both hot and humid or cold and damp periods of the year might have a direct effect on the cardiovascular system. Because of the strong inverse correlation between rainfall and water hardness,'5 data from South Wales'4 and England and Wales 14'17 were analysed to determine how important long- and short-term climatic factors were as correlates of mortality from ischaemic heart disease and whether they would account for the apparent association of mortality with water hardness. The results indicated that water calcium owed its association with heart disease almost entirely to its own association with temperature and rainfall. The possibility that the relation between temperature and mortality from ischaemic heart disease is causal has been discussed recently.'8 This fascinating story is not tied up by any means. Reports of the association continue to appear,'9 20 and to be explained away.21 Nevertheless, despite all these inconsistencies in the evidence two official publications have made recommenda-
390
BRITISH MEDICAL JOURNAL
tions. One22 states that: ". . . any propoOals for softening the water supply in any part of the country [UK] should be considered in the light of knowledge about the observed positive relationship between the death rate from ischaemic heart disease and the softness of the local water supply." The second23 states: "Where domestic water softeners are used, it might be prudent for drinking-water to be taken from the mains supply." Both are counsels for inaction, which is the most our present knowledge should allow. Schroeder, H A, J'ournal of the American Medical Association, 1960, 172, 1902. 2Schroeder, H A, Journal of Chronic Diseases, 1960, 12, 568. 3 Morris, J N, Crawford, M D, and Heady, J A, Lancet, 1961, 1, 860. 4 Morris, J N, Crawford, M D, and Heady, J A, Lancet, 1962, 2, 506. Heyden, S, Journal of Chronic Diseases, 1976, 29, 149. 6 Crawford, M D, Gardner, M J, and Morris, J N, Lancet, 1968, 1, 827. 7Anderson, T W, Le Riche, W H, and Mackay, J S, New England J7ournal of Medicine, 1969, 280, 805. 8 Tyroler, H A, in The Community as an Epidemiological Laboratory, eds I I Kessler and M L Levin, p 100. Baltimore, Johns Hopkins, 1970. 9 Lindeman, R D, and Assenzo, J R, American Journal of Public Health, 1964, 54, 1071. '0 Allwright, S P A, et al, Lancet, 1974, 2, 860. 11 Comstock, G W, American Journal of Epidemiology, 1971, 94, 1. 12 Mulcahy, R, Journal of the Irish Medical Association, 1964, 55, 17. 13 Elwood, P C, Abernethy, M, and Morton, M, Lancet, 1974, 2, 1470. 14 Roberts, C J, and Lloyd, S, Lancet, 1972, 1, 1091. 15 Gardner, M J, Crawford, M D, and Morris, J N, British Journal of Preventive and Social Medicine, 1969, 23, 133. 16 Dudley, E F, Beldin, R A, and Johnson, B C, Journal of Chronic Diseases, 1969, 22, 25. 17 West, R R, Lloyd, S, and Roberts, C J, British Journal of Preventive and Social Medicine, 1973, 27, 36. 18 West, R R, and Lowe, C R, International3Journal of Epidemiology, 1976, 5, 195. 19 Anderson, T W, et al, Canadian Medical Association Journal, 1975, 113, 199. 20 Chipperfield, B, et al, Lancet, 1976, 1, 121. 21 Campos, A T, Lancet, 1976, 1, 1244. 22 DHSS, Report on Health and Social Subjects 7, Diet and Coronary Heart Disease. London, HMSO, 1974. 23 Report of a Joint Working Party of the Royal College of Physicians of London and the British Cardiac Society, Journal of the Royal College of Physicians, 1976, 10, 213; Royal College of Physicians and British Cardiac Society, British Medical3Journal, 1976, 1, 881.
pandemic Is the cholera ; waning? *D
The current pandemic of cholera, if not on the decline, may be at least becoming stabilised.' In 1975 the number of countries notifying cholera was the smallest since 1970. The disease extended to only one new country in Africa and only one in Asia. The trend seems generally downwards. In 1970 cholera was reported by 36 countries with a total of 155 555 cases. In 1975 the score was 29 countries and 87 475 cases. The drop in numbers of countries and cases was most notable in Africa. On the whole the same countries remained infected in Asia. In Europe cholera continued in limited "epidemic" form in Portugal and there were some possibly "endemic" cases in France and Spain. Cases were imported into Britain and Italy. This fall is encouraging, especially in view of the improvement in national and international surveillance which has brought some sort of reality to the figures quoted. Earlier in the pandemic reported outbrtaks sometimes led to drastic long-term and financially damaging measures by neighbouring countries, including restriction of imports and closure of ports and airports; and this resulted in resistance to reporting the presence of the disease and so made world figures unrealistic. The introduction of International Health Regulations in 1969 in place of the more rigid International Sanitary Regula-
14 AUGUST 1976
tions seems to have reduced the fear of unwarranted sanctions.2
3
The current pandemic has resulted from the spread of the El Tor vibrio, discovered in 1906 in a village of the same name in the Sinai Peninsula. For many years regarded as a maverick, and not included in the WHO list of choleraproducing vibrios, the organism eventually reappeared in 1938 as the cause of a mild cholera-like disease in Sulawesi, and cases were reported in Java and Singapore during the second world war. A decade later the new vibrio spread rapidly throughout South-east Asia. In 1961 there were over 10 000 cases, many severe, in the Philippines. By 1963 Thailand, the Khmer Republic, Vietnam, Hong Kong, Burma, India, and both Pakistans became affected. In 1966 the disease appeared in Iraq and Syria and then spread westward, reaching eastern Europe, North Africa, and Africa south of the Sahara (probably for the first time in history). Imported cases began to appear in western Europe, including Britain, and sporadic outbreaks occurred in other countries, especially Portugal. Except in Bangladesh the El Tor organism now occupies the former endemic areas of the classical vibrios, which have otherwise practically disappeared. The spread of the vibrio has been encouraged by the increasing ease and frequency of contacts in infected areas. For the initial transfer over long distances the aeroplane has been the major agent. Over short distances the ship has also played its part, as in the (presumed) transfer from Sulawesi to Java. Once established, the infection has spread within a country and to its neighbours through movements of people across uncontrolled terrain, national borders, and along rivers and coastal areas by fisherman, as in West Africa. The establishment of the disease depends on the coexistence of an insanitary environment and a population ignorant of hygiene. These two factors are common to the spread of all vibrios, but the El Tor organism has certain advantages over its rivals. Once it reaches receptive insanitary areas it tends to remain in them and may well stay there until sanitation improves sufficiently; and so new endemic areas are set up. The new vibrio is more persistent in the human body than the others and is commonly excreted in the faeces for two to three weeks after infection, whether or not accompanied by symptoms. There are also occasional chronic carriers, who are not found with the classical infections. Clinical effects may be as severe as in any other form of cholera, or they may be mild or absent. However, the patient, the convalescent, and the silent case all excrete the organism. Modern methods of treatment are excellent if offered early, but in large areas of the developing world, where cholera is most frequent, treatment is often unavailable. Where poverty, inaccessibility, and ignorance reign, the death rate is high. In 1976 cholera is still very much with us, spread across the world, except, most remarkably, in the Americas-a possible pointer to control elsewhere. In contrast to our control of smallpox we have not yet got the weapons to eradicate cholera. We certainly cannot rely on the present inefficient vaccine. In the long run-and it may be a very long run-the final answer must be to make receptive areas ununreceptive by transformation of their sanitation. This is a problem for medical and health education and the provision and proper use of national and international funds. IWorld Health Organisation, Weekly Epidemiological Record, 1976, 51, 137. 2 World Health Organisation, International Health Regulations, 1969, 2nd edn. Geneva, World Health Organisation, 1974. 3 World Health Organisation, International Sanitary Regulations, 1951, annotated ed. Geneva, World Health Organisation, 1957.
