124
account the
importance of tobacco products other than cigarettes, as the Indian experience shows. On the basis of comparisons between highest and lowest observed cancer incidence in various populations of the world, it is estimated33 that a substantial reduction in incidence could be achieved by the elimination of tobacco:
competing interests of the child and the trapped community should be faced squarely, and the decision made locally by ministries of health. It should not be made by default in New York by UNICEF (and other agencies) denying that the demographic trap exists and insisting that reducing child mortality in this way reduces fertility. Department of Public Health Medicine, University of Leeds, Leeds LS2 9LN, UK
MAURICE KING
1. King MH. Overpopulation and death in childhood. Lancet 1990; 336: 1312. 2. Tahzib F. Nigeria: talking about food. Lancet 1990; 336: 1371.
Aspirin, warfarin, and
recurrent stroke
SIR,-Dr Alter and his colleagues (June 1, p 1343) conclude that
Applying these estimates to 1980 data, we end up with between 1 million and 15 million cancers per year induced by tobacco use. This may be at best an educated guess but it does provide some indication in addition to tobacco-attributable mortality, which has been more thoroughly studied. In view of the fear of cancer in the general population, the low survival rate of most tobacco-related cancers, and the suffering of cancer patients, it seems inconceivable that so many people still smoke. Unit of Analytical Epidemiology, International Agency for Research 69372 Lyon cedex 8, France
1. World Health
Organisation.
on
Cancer,
ANNIE J. SASCO
Tobacco-attributable
mortality: global
estimates and
projections. Tobacco Alert 1991 (Jan); 4-5, 7. 2. Shultz JM. Smoking-attributable mortality and years of potential life lost-United States, 1988. MMWR 1991; 40: 62-63, 69-71. 3. Tomatis L, Aitio A, Day NE, et al, eds. Cancer: causes, occurrence and control. (IARC Sci Publ no 100). Lyon: International Agency for Research on Cancer, 1990. 4. Parkin DM, Laara E, Muir CS. Estimates of the worldwide frequency of sixteen major cancers in 1980. Int J Cancer 1988; 41: 184-97. 5. Doll R, Peto R. The causes of cancer: quantitative estimates of avoidable risks of cancer in the United States today. J Natl Cancer Inst 1981; 66: 1191-308. 6. Wald N, Kiryluk S, Darby S, Pike M, Peto R, eds. UK smoking statistics. Oxford: Oxford University Press, 1988. 7. IARC monographs on the evaluation of the carcinogenic risk of chemicals to humans vol XXXVIII, tobacco smoking. Lyon: International Agency for Research on Cancer, 1986. 8. IARC Monographs on the evaluation of the carcinogenic risk of chemicals to humans vol XXXVII, tobacco habits other than smoking: betel quid and areca nut chewing and some related nitrosamines. Lyon: International Agency for Research on Cancer, 1985. 9. Reducing the health consequences of smoking: 25 years of progress: a report to the Surgeon-General. Rockville, Maryland: US Department of Health and Human Services, Public Health Service, Center for Chronic Disease Prevention and Health Promotion, Office of Smoking and Heath, 1989. 10. Muir CS, Waterhouse J, Mack T, Powell J, Whelan S, eds. Cancer incidence in five continents, vol V (IARC Sci Publ no 88). Lyon: International Agency for Research on Cancer, 1987.
Malaria control and the
aspirin and warfarin are not effective in long-term secondary prevention of stroke. We disagree with this interpretation of their findings. The reductions observed are not conventionally significant by the chi-square test, but the sample size was small and confidence intervals (CI) should have been provided.l,22 Aspirin was associated with a 30% relative reduction (95% CI - 68% [reduction] to +51% [excess]) and warfarin a 32% reduction (95% CI -72% to +68%) in the odds of recurrent stroke. The Lehigh Valley cohort thus lacks the statistical power to detect a moderate, but clinically worthwhile, benefit. The 30% reduction in stroke with aspirin reported by Alter et al is almost identical to the 27% reduction (95% CI -15% to -39%) in non-fatal stroke reported in an overview of randomised trials of antiplatelet agents in long-term secondary prevention. The reductions in stroke with anticoagulation are similar to those observed in three primary prevention studies of patients with non-valvular atrial fibrillation.Thus Alter’s observations, in a non-randomised study lacking statistical power, are compatible with data from randomised trials which show clear evidence that anti-platelet drugs are effective in long-term secondary prevention; the role of anticoagulants in long-term secondary prevention will be clarified by trials in progress
or
being planned.
Department of Clinical Neurosciences, Western General Hospital, Edinburgh EH4 2XU, UK
PETER SANDERCOCK DAVID DUNBABIN
1. Sandercock PAG. The odds ratio: a useful tool in neurosciences. J Neurol Neurosurg Psychiatry 1989; 52: 817-20. 2. Gardner MJ, Altman DG. Statistics with confidence: confidence intervals and statistical guidelines. London: British Medical Journal, 1989. 3. Antiplatelet Trialists’ Collaboration. Secondary prevention of vascular disease by prolonged antiplatelet treatment. Br Med J 1988; 296: 320-31. 4. Petersen P, Boysen G, Godtfredsen J, Andersen E, Andersen B. Placebo-controlled, randomised trial of warfarin and aspirin for prevention of thromboembolic complications in chronic atrial fibrillation. Lancet 1989; i: 175-80. 5. Stroke Prevention in Arial Fibrillation Study Group. Preliminary report of the stroke prevention in atrial fibrillation study. N Engl J Med 1990; 322: 863-68. 6. Boston Area Anticoagulation Trial for Atrial Fibrillation. The effect of low-dose warfarin on the risk of stroke in patients with nonrheumatic atrial fibrillation. N Engl J Med 1990, 323: 150-11.
demographic trap
SiR,—You write that the "simple approach to malaria control by the use of impregnated bed nets should be welcomed wholeheartedly" (June 22 editorial, p 1515) as reducing the malaria specific and the overall mortality by 70% and 63%, respectively, in children aged 1-4 years. In parts of west Africa childhood deaths from malaria approach 10% each year, so these nets can be expected to have a substantial demographic effect on a population in which the average mother has six children, and which will already double in 20 years. Dr J. Seaman (Save the Children) suggests that Nigeria may be in the "trap closing" stage of the demographic trapl in that it is likely to starve before it undergoes a demographic transition. The Nutrition Society of Nigeria already reports that "even the most basic staple foods seem to be beyond the reach of the average Nigerian, who now gets less than 80% of the recommended intake with women and children getting even less".2Wholehearted welcome should therefore be tempered with demographic anxiety. Over the years several malariologists have warned about the demographic effects of malaria control. The ethical dilemma of the
Breech extraction facilitated by glyceryl trinitrate sublingual spray SIR,-Acceptable maternal and fetal outcome can be achieved by vaginal delivery of twin pregnancy when the first twin is in a cephalic presentation and the second is in any presentation.1 However, when the second twin is in a transverse lie, total breech extraction is sometimes the best method. We report a case in which sublingual nitroglycerine was used as a uterine relaxant to facilitate the delivery of the aftercoming twin during the breech extraction procedure when the uterus contracted down on the operator’s forearm. A 25-year-old woman (gravida 2, para 1) presented in active labour with a twin pregnancy at 40 weeks. The antepartum course had been uncomplicated. The twins had appropriate growth for gestational age. The first twin was in a cephalic lie. The second was in a transverse lie with the fetal dorsum cephalad. In early labour, the patient consented to a trial of labour that included the plan to
account the
importance of tobacco products other than cigarettes, as the Indian experience shows. On the basis of comparisons between highest and lowest observed cancer incidence in various populations of the world, it is estimated33 that a substantial reduction in incidence could be achieved by the elimination of tobacco:
competing interests of the child and the trapped community should be faced squarely, and the decision made locally by ministries of health. It should not be made by default in New York by UNICEF (and other agencies) denying that the demographic trap exists and insisting that reducing child mortality in this way reduces fertility. Department of Public Health Medicine, University of Leeds, Leeds LS2 9LN, UK
MAURICE KING
1. King MH. Overpopulation and death in childhood. Lancet 1990; 336: 1312. 2. Tahzib F. Nigeria: talking about food. Lancet 1990; 336: 1371.
Aspirin, warfarin, and
recurrent stroke
SIR,-Dr Alter and his colleagues (June 1, p 1343) conclude that
Applying these estimates to 1980 data, we end up with between 1 million and 15 million cancers per year induced by tobacco use. This may be at best an educated guess but it does provide some indication in addition to tobacco-attributable mortality, which has been more thoroughly studied. In view of the fear of cancer in the general population, the low survival rate of most tobacco-related cancers, and the suffering of cancer patients, it seems inconceivable that so many people still smoke. Unit of Analytical Epidemiology, International Agency for Research 69372 Lyon cedex 8, France
1. World Health
Organisation.
on
Cancer,
ANNIE J. SASCO
Tobacco-attributable
mortality: global
estimates and
projections. Tobacco Alert 1991 (Jan); 4-5, 7. 2. Shultz JM. Smoking-attributable mortality and years of potential life lost-United States, 1988. MMWR 1991; 40: 62-63, 69-71. 3. Tomatis L, Aitio A, Day NE, et al, eds. Cancer: causes, occurrence and control. (IARC Sci Publ no 100). Lyon: International Agency for Research on Cancer, 1990. 4. Parkin DM, Laara E, Muir CS. Estimates of the worldwide frequency of sixteen major cancers in 1980. Int J Cancer 1988; 41: 184-97. 5. Doll R, Peto R. The causes of cancer: quantitative estimates of avoidable risks of cancer in the United States today. J Natl Cancer Inst 1981; 66: 1191-308. 6. Wald N, Kiryluk S, Darby S, Pike M, Peto R, eds. UK smoking statistics. Oxford: Oxford University Press, 1988. 7. IARC monographs on the evaluation of the carcinogenic risk of chemicals to humans vol XXXVIII, tobacco smoking. Lyon: International Agency for Research on Cancer, 1986. 8. IARC Monographs on the evaluation of the carcinogenic risk of chemicals to humans vol XXXVII, tobacco habits other than smoking: betel quid and areca nut chewing and some related nitrosamines. Lyon: International Agency for Research on Cancer, 1985. 9. Reducing the health consequences of smoking: 25 years of progress: a report to the Surgeon-General. Rockville, Maryland: US Department of Health and Human Services, Public Health Service, Center for Chronic Disease Prevention and Health Promotion, Office of Smoking and Heath, 1989. 10. Muir CS, Waterhouse J, Mack T, Powell J, Whelan S, eds. Cancer incidence in five continents, vol V (IARC Sci Publ no 88). Lyon: International Agency for Research on Cancer, 1987.
Malaria control and the
aspirin and warfarin are not effective in long-term secondary prevention of stroke. We disagree with this interpretation of their findings. The reductions observed are not conventionally significant by the chi-square test, but the sample size was small and confidence intervals (CI) should have been provided.l,22 Aspirin was associated with a 30% relative reduction (95% CI - 68% [reduction] to +51% [excess]) and warfarin a 32% reduction (95% CI -72% to +68%) in the odds of recurrent stroke. The Lehigh Valley cohort thus lacks the statistical power to detect a moderate, but clinically worthwhile, benefit. The 30% reduction in stroke with aspirin reported by Alter et al is almost identical to the 27% reduction (95% CI -15% to -39%) in non-fatal stroke reported in an overview of randomised trials of antiplatelet agents in long-term secondary prevention. The reductions in stroke with anticoagulation are similar to those observed in three primary prevention studies of patients with non-valvular atrial fibrillation.Thus Alter’s observations, in a non-randomised study lacking statistical power, are compatible with data from randomised trials which show clear evidence that anti-platelet drugs are effective in long-term secondary prevention; the role of anticoagulants in long-term secondary prevention will be clarified by trials in progress
or
being planned.
Department of Clinical Neurosciences, Western General Hospital, Edinburgh EH4 2XU, UK
PETER SANDERCOCK DAVID DUNBABIN
1. Sandercock PAG. The odds ratio: a useful tool in neurosciences. J Neurol Neurosurg Psychiatry 1989; 52: 817-20. 2. Gardner MJ, Altman DG. Statistics with confidence: confidence intervals and statistical guidelines. London: British Medical Journal, 1989. 3. Antiplatelet Trialists’ Collaboration. Secondary prevention of vascular disease by prolonged antiplatelet treatment. Br Med J 1988; 296: 320-31. 4. Petersen P, Boysen G, Godtfredsen J, Andersen E, Andersen B. Placebo-controlled, randomised trial of warfarin and aspirin for prevention of thromboembolic complications in chronic atrial fibrillation. Lancet 1989; i: 175-80. 5. Stroke Prevention in Arial Fibrillation Study Group. Preliminary report of the stroke prevention in atrial fibrillation study. N Engl J Med 1990; 322: 863-68. 6. Boston Area Anticoagulation Trial for Atrial Fibrillation. The effect of low-dose warfarin on the risk of stroke in patients with nonrheumatic atrial fibrillation. N Engl J Med 1990, 323: 150-11.
demographic trap
SiR,—You write that the "simple approach to malaria control by the use of impregnated bed nets should be welcomed wholeheartedly" (June 22 editorial, p 1515) as reducing the malaria specific and the overall mortality by 70% and 63%, respectively, in children aged 1-4 years. In parts of west Africa childhood deaths from malaria approach 10% each year, so these nets can be expected to have a substantial demographic effect on a population in which the average mother has six children, and which will already double in 20 years. Dr J. Seaman (Save the Children) suggests that Nigeria may be in the "trap closing" stage of the demographic trapl in that it is likely to starve before it undergoes a demographic transition. The Nutrition Society of Nigeria already reports that "even the most basic staple foods seem to be beyond the reach of the average Nigerian, who now gets less than 80% of the recommended intake with women and children getting even less".2Wholehearted welcome should therefore be tempered with demographic anxiety. Over the years several malariologists have warned about the demographic effects of malaria control. The ethical dilemma of the
Breech extraction facilitated by glyceryl trinitrate sublingual spray SIR,-Acceptable maternal and fetal outcome can be achieved by vaginal delivery of twin pregnancy when the first twin is in a cephalic presentation and the second is in any presentation.1 However, when the second twin is in a transverse lie, total breech extraction is sometimes the best method. We report a case in which sublingual nitroglycerine was used as a uterine relaxant to facilitate the delivery of the aftercoming twin during the breech extraction procedure when the uterus contracted down on the operator’s forearm. A 25-year-old woman (gravida 2, para 1) presented in active labour with a twin pregnancy at 40 weeks. The antepartum course had been uncomplicated. The twins had appropriate growth for gestational age. The first twin was in a cephalic lie. The second was in a transverse lie with the fetal dorsum cephalad. In early labour, the patient consented to a trial of labour that included the plan to
