678
Iodisation of salt SIR,-Your Round the World article (Jan 26, p 226) states that the universal iodisation of salt is opposed in India because this would make salt more expensive in areas that need no extra iodine. A more serious objection is that salt will be represented as beneficial to health at a time when most of us are trying to reduce salt intake to prevent hypertension. After Intersalt, which showed the futility of half-measures,1,2 the ceiling daily sodium intake of 100 mmol recommended by the US Public Health Service3 seems generous, and there is a new directive that a further reduction to 75 mmol would probably confer greater health benefits.4 Noting the need to prevent hypertension, a joint WHO/UNICEF/ICCIDD task force has recommended raising the concentration of iodine in iodised salt to 100 mg/kgbut an intake of 150 µg of iodine would still be accompanied by 26 mmol of unnecessary added salt-no less than a third of the daily 75 mmol. We have found that Tasmanians with sodium excretion rates below 75 mmol per day are people who avoid the domestic use of salt almost completely. Our survey of 24 h electrolyte excretion (n 54) in Hobart, in conjunction with the third National Heart Foundation Risk Factor Prevalence Study, showed that those who achieved sodium excretion rates below 75 mmol per day (n=9) reported using salt in cooking or at the table on average less than once in the previous 3 days (a mean of 0-7 times and 0-6 times, respectively). Tasmania (an endemic goitre area) controlled iodine deficiency in the 1960s by adding potassium iodate to bread improvers.6 When iodine compounds were used later to sterilise dairy equipment, milk alone supplied enough iodine to prevent goitre, and potassium iodate was discontinued. Iodised salt was never needed and is no longer promoted in Tasmania for goitre prevention. The approach in each culture is dictated by the local diet and customs, and it may be difficult in some areas to find a better vehicle for iodine than salt. The need to correct iodine deficiency amongst an estimated 800 million people throughout the world is very urgent,7 but another massive challenge to public health in the 21st century will be the treatment and prevention of hypertension. This is already an issue of major concern in north Asia, where it often coexists with iodine deficiency. It is inconceivable that some 10-20% of the world’s adults can be offered drug treatment for life, even if it were desirable. For both treatment and prevention, non-pharmacological methods are needed, including the avoidance of salt. The iodisation of salt in iodine-deficient districts can only postpone the eventual primary prevention of hypertension in those =
areas.
Menzies Centre for Population Health Research, Hobart, Tasmania 7000, Australia
TREVOR C. BEARD TERENCE DWYER
1. Intersalt Cooperative Research Group. Intersalt: an international study of electrolyte excretion and blood pressure: results for 24-hour urinary sodium and potassium excretion. Br Med J 1988; 297: 319-28. 2. Beard TC. Hypertension after Intersalt: prospects for prevention. J Cardiovasc Pharmacol 1990; 16 (suppl 7): S31-34. 3. McGinnis JM Clarification of sodium figure quoted in 1990 objectives for the nation. Publ Health Rep 1986; 101: 123-24. 4. Committee on Diet and Health, National Research Council. Diet and health: implications for reducing chronic disease risk Washington, DC: National Academy Press, 1989: 16-17. 5. Hetzel BS. Iodine deficiency disorders. Lancet 1988; i: 1386. 6. Clements FW, Gibson HB, Howeler-Coy JF. Goitre studies in Tasmania. Bull WHO
1968; 38: 297-318. 7. Hetzel BS. The story of iodine deficiency: Oxford: Oxford University Press, 1989.
an
international
challenge
in nutrition.
Helping hospitals in Eastern Europe SIR,- The initiative from Treliske Hospital described by Dr Cassidy (Feb 9, p 353) makes heartening reading. The events of the past year have revealed both the needs and the potential for aid in Eastern Europe. But please let us not forget those hospitals in many parts of the developing world that have long suffered similar deprivations. Shortages of even basic supplies are widespread and equipment is outdated or unserviceable. Isolation from colleagues and shortages of books and journals compound these difficulties. Yet the demand increases monthly from a population whose confidence in their hospital continues to grow.
Twinning provides a direct, flexible means of giving help. Money and supplies are needed, of course, and even small amounts are valuable. So is support for the staff in the form of small gifts; soap and soup are appreciated out of all proportion to their cost. A regular locum to allow hard-pressed clinicians necessary leave would benefit both partners. Pathology services could be organised and research projects initiated. There will be an open meeting of Friends of Overseas Hospitals on Friday, March 22, at the George Inn, 77 Borough High Street, London SE1 (next to London Bridge station and Guy’s Hospital), from 6 pm. The theme is Third World Hospitals: what do they do/what do they need and what can we do?
12 Turner Close,
ANNE SAVAGE
London NW11 6TU, UK
Psychiatry and general practice SIR,-In his review of Prof Patricia Casey’s book A Guide to Psychiatry in Primary Care Dr O’Dowd (Feb 9, p 349) suggests that the romance between psychiatrists and general practitioners is over. He confines the poorly adaptable psychiatrist to the treatment of acute psychoses and to the care of established chronic patients (it is
chronicity of patients or of duration of illness is the basis of this new diagnostic category). In place of the psychiatrist comes the more adaptable and socially acceptable psychologist. O’Dowd’s view is undermined by the lack of any evidence for his arguments. He would do well to become familiar with research indicating close working relationships between general practitioners and psychiatrists, both in the rest of Nottingham and throughout the UK.1,2 Far from the divorce he suggests, relations between general practitioners and their psychiatric colleagues in the 1990s are one of mutual trust and occasional "bliss". O’Dowd’s view seems more symptomatic of the wounded ruminations of a jilted spinster than the result of mature deliberations of incompatible adults. not clear whether
Mapperley Hospital, Nottingham NG3 6AA, UK 1.
BRIAN FERGUSON
Ferguson B. Psychiatric clinics in general practice—an asset for primary care. Health Trends 1987; 19: 22. I, Yellowlees A. Scottish psychiatrists in J 1987; 153: 663-66. majority. Br Psychiatry
2. Pullen
Is
primary health care settings: a silent
intelligence illusory?
SIR,- W were surprised by your support (Jan 26, p 208) for the argument of Dr M. J. A. Howe that "intelligence may be illusory after all". Howe’s point is the trivial, if correct one, that IQ estimates, being mere numbers, are only descriptive and have little explanatory potential. His view is analogous to pointing out that health records are themselves only descriptive, and then going on to say that neither individual health records nor other individual features of patients can be explained as arising from their differences in general health. Are there no real and lasting differences between people in health? Are there no healthy lifestyles simply because health records can only be descriptive? How can the results of research based on IQ estimates be interpreted without accepting that there are enduring and important underlying differences between individuals’ general intelligence? A forty-year follow-up of Canadian servicemen found IQ values to be highly stable throughout adult life.’ A publication search has shown IQ to be the only major predictor of job success in the US.2 Although psychologists have searched for uncorrelated mental abilities (Howe’s "separately measurable units"), no such disunitarian picture has emerged. Mental abilities are hierarchically ordered, general intelligence accounting for much of the substantial covariation between abilities found in population samples.3 What underlies measurable IQ differences? A meta-analysis of some forty laboratory studies shows that mental speed of intake for elementary perceptual information-eg, line lengths-is substantially correlated (r=0’50) with IQ differences among normal young adults.’ Such elementary information handling differences probably express themselves over the course of
Iodisation of salt SIR,-Your Round the World article (Jan 26, p 226) states that the universal iodisation of salt is opposed in India because this would make salt more expensive in areas that need no extra iodine. A more serious objection is that salt will be represented as beneficial to health at a time when most of us are trying to reduce salt intake to prevent hypertension. After Intersalt, which showed the futility of half-measures,1,2 the ceiling daily sodium intake of 100 mmol recommended by the US Public Health Service3 seems generous, and there is a new directive that a further reduction to 75 mmol would probably confer greater health benefits.4 Noting the need to prevent hypertension, a joint WHO/UNICEF/ICCIDD task force has recommended raising the concentration of iodine in iodised salt to 100 mg/kgbut an intake of 150 µg of iodine would still be accompanied by 26 mmol of unnecessary added salt-no less than a third of the daily 75 mmol. We have found that Tasmanians with sodium excretion rates below 75 mmol per day are people who avoid the domestic use of salt almost completely. Our survey of 24 h electrolyte excretion (n 54) in Hobart, in conjunction with the third National Heart Foundation Risk Factor Prevalence Study, showed that those who achieved sodium excretion rates below 75 mmol per day (n=9) reported using salt in cooking or at the table on average less than once in the previous 3 days (a mean of 0-7 times and 0-6 times, respectively). Tasmania (an endemic goitre area) controlled iodine deficiency in the 1960s by adding potassium iodate to bread improvers.6 When iodine compounds were used later to sterilise dairy equipment, milk alone supplied enough iodine to prevent goitre, and potassium iodate was discontinued. Iodised salt was never needed and is no longer promoted in Tasmania for goitre prevention. The approach in each culture is dictated by the local diet and customs, and it may be difficult in some areas to find a better vehicle for iodine than salt. The need to correct iodine deficiency amongst an estimated 800 million people throughout the world is very urgent,7 but another massive challenge to public health in the 21st century will be the treatment and prevention of hypertension. This is already an issue of major concern in north Asia, where it often coexists with iodine deficiency. It is inconceivable that some 10-20% of the world’s adults can be offered drug treatment for life, even if it were desirable. For both treatment and prevention, non-pharmacological methods are needed, including the avoidance of salt. The iodisation of salt in iodine-deficient districts can only postpone the eventual primary prevention of hypertension in those =
areas.
Menzies Centre for Population Health Research, Hobart, Tasmania 7000, Australia
TREVOR C. BEARD TERENCE DWYER
1. Intersalt Cooperative Research Group. Intersalt: an international study of electrolyte excretion and blood pressure: results for 24-hour urinary sodium and potassium excretion. Br Med J 1988; 297: 319-28. 2. Beard TC. Hypertension after Intersalt: prospects for prevention. J Cardiovasc Pharmacol 1990; 16 (suppl 7): S31-34. 3. McGinnis JM Clarification of sodium figure quoted in 1990 objectives for the nation. Publ Health Rep 1986; 101: 123-24. 4. Committee on Diet and Health, National Research Council. Diet and health: implications for reducing chronic disease risk Washington, DC: National Academy Press, 1989: 16-17. 5. Hetzel BS. Iodine deficiency disorders. Lancet 1988; i: 1386. 6. Clements FW, Gibson HB, Howeler-Coy JF. Goitre studies in Tasmania. Bull WHO
1968; 38: 297-318. 7. Hetzel BS. The story of iodine deficiency: Oxford: Oxford University Press, 1989.
an
international
challenge
in nutrition.
Helping hospitals in Eastern Europe SIR,- The initiative from Treliske Hospital described by Dr Cassidy (Feb 9, p 353) makes heartening reading. The events of the past year have revealed both the needs and the potential for aid in Eastern Europe. But please let us not forget those hospitals in many parts of the developing world that have long suffered similar deprivations. Shortages of even basic supplies are widespread and equipment is outdated or unserviceable. Isolation from colleagues and shortages of books and journals compound these difficulties. Yet the demand increases monthly from a population whose confidence in their hospital continues to grow.
Twinning provides a direct, flexible means of giving help. Money and supplies are needed, of course, and even small amounts are valuable. So is support for the staff in the form of small gifts; soap and soup are appreciated out of all proportion to their cost. A regular locum to allow hard-pressed clinicians necessary leave would benefit both partners. Pathology services could be organised and research projects initiated. There will be an open meeting of Friends of Overseas Hospitals on Friday, March 22, at the George Inn, 77 Borough High Street, London SE1 (next to London Bridge station and Guy’s Hospital), from 6 pm. The theme is Third World Hospitals: what do they do/what do they need and what can we do?
12 Turner Close,
ANNE SAVAGE
London NW11 6TU, UK
Psychiatry and general practice SIR,-In his review of Prof Patricia Casey’s book A Guide to Psychiatry in Primary Care Dr O’Dowd (Feb 9, p 349) suggests that the romance between psychiatrists and general practitioners is over. He confines the poorly adaptable psychiatrist to the treatment of acute psychoses and to the care of established chronic patients (it is
chronicity of patients or of duration of illness is the basis of this new diagnostic category). In place of the psychiatrist comes the more adaptable and socially acceptable psychologist. O’Dowd’s view is undermined by the lack of any evidence for his arguments. He would do well to become familiar with research indicating close working relationships between general practitioners and psychiatrists, both in the rest of Nottingham and throughout the UK.1,2 Far from the divorce he suggests, relations between general practitioners and their psychiatric colleagues in the 1990s are one of mutual trust and occasional "bliss". O’Dowd’s view seems more symptomatic of the wounded ruminations of a jilted spinster than the result of mature deliberations of incompatible adults. not clear whether
Mapperley Hospital, Nottingham NG3 6AA, UK 1.
BRIAN FERGUSON
Ferguson B. Psychiatric clinics in general practice—an asset for primary care. Health Trends 1987; 19: 22. I, Yellowlees A. Scottish psychiatrists in J 1987; 153: 663-66. majority. Br Psychiatry
2. Pullen
Is
primary health care settings: a silent
intelligence illusory?
SIR,- W were surprised by your support (Jan 26, p 208) for the argument of Dr M. J. A. Howe that "intelligence may be illusory after all". Howe’s point is the trivial, if correct one, that IQ estimates, being mere numbers, are only descriptive and have little explanatory potential. His view is analogous to pointing out that health records are themselves only descriptive, and then going on to say that neither individual health records nor other individual features of patients can be explained as arising from their differences in general health. Are there no real and lasting differences between people in health? Are there no healthy lifestyles simply because health records can only be descriptive? How can the results of research based on IQ estimates be interpreted without accepting that there are enduring and important underlying differences between individuals’ general intelligence? A forty-year follow-up of Canadian servicemen found IQ values to be highly stable throughout adult life.’ A publication search has shown IQ to be the only major predictor of job success in the US.2 Although psychologists have searched for uncorrelated mental abilities (Howe’s "separately measurable units"), no such disunitarian picture has emerged. Mental abilities are hierarchically ordered, general intelligence accounting for much of the substantial covariation between abilities found in population samples.3 What underlies measurable IQ differences? A meta-analysis of some forty laboratory studies shows that mental speed of intake for elementary perceptual information-eg, line lengths-is substantially correlated (r=0’50) with IQ differences among normal young adults.’ Such elementary information handling differences probably express themselves over the course of
