Alterations of dietary fat that reduce serum cholesterol are beneficial to people who have the highest risk of death from coronary heart disease (CHD). For other people the benefits are less clear; there is a suggestion (hotly disputed) that cholesterol-lowering by drugs, and possibly by diet, increases the risk of non-CHD death, for reasons that are not understood. Furthermore, fat intake interacts with other dietary and non-dietary factors. The consequences of altering dietary fat seem to be more complex and uncertain than have hitherto been supposed.
Toronto Working Group: Asymptomatic hypercholesterolemia: A clinical policy review. J Clin Epidemiol1990, 43:1029–1121. The authors examine in detail the evidence relating to asymptomatic hypercholesterolaemia. They advocate serum cholesterol testing in middle-aged men with other risk factors followed by dietary advice. They are cautious about the management of other groups and advocate an individualized approach.
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RavnskovU: Cholesterol lowering trials in coronary heart disease: Frequency of citation and outcome. BMJ1992, 305:15–19. The author examines 22 cholesterol-lowering trials and papers that review them. He concludes that lowering serum cholesterol does not reduce mortality and is unlikely to prevent CHD; claims to the contrary are based on preferential citation of supportive trials.
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WoodhillJMPalmerAJLeelarthaepinBMcGilchristCBlacketRB: Low fat, low cholesterol diet in secondary prevention of coronary heart disease. Adv Exp Med Biol1978, 109:317–330.
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Multiple Risk Factor Intervention Trial Research Group: Multiple Risk Factor Intervention Trial: Risk factor changes and mortality results. JAMA1982, 248:1465–1477.
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World Health Organization Regional Office for Europe: Rehabilitation and comprehensive secondary prevention after acute myocardial infarction. Report on a study. Copenhagen: Euro Reports and Studies 84, WHO; 1983.
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HjermannIHolmeILerenP: Oslo study diet and antismoking trial: Results after 102 months. Am J Med1986, 80 (suppl 2A):7–11.
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World Health Organization European Collaborative Group: European collaborative trial of multifactorial prevention of coronary heart disease: Final report on the 6-year results. Lancet1986, i:869–872.
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WilhelmsenLBerglundGElmfeldtDTibblinGWedelHPennertK: The multifactor primary prevention trial in Göteborg, Sweden. Eur Heart J1986, 7:279–288.
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FrantzIDDawsonEAAshmanPLGatewoodLCBartschGEKubaK: Test of effect of lipid lowering by diet on cardiovascular risk: The Minnesota Coronary Survey. Arteriosclerosis1989, 9:129–135.
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BurrMLFehilyAMGilbertJFRogersSHollidayRMSweet-namPM: Effects of changes in fat, fish and fibre intakes on death and myocardial infarction: Diet and Reinfarction Trial (DART). Lancet1989, ii:757–761.
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SinghRBRastogiSSVermaRLaxmiBSingRGhoshS: Randomized controlled trial of cardioprotective diet in patients with recent acute myocardial infarction: Results of one-year follow up. BMJ1992, 304:1015–1019.
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De LorgerilMSalenPMartinJLMamelleNRenaudS, for the Investigators of the Lyon Diet-Heart Study: French Mediterranean diet is highly protective against recurrent coronary events [abstract]. Eur Heart J1993, 14 (suppl):19.
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McCormickJSkrabanekP: Coronary heart disease is not preventable by population interventions. Lancet1988, ii:839–841. The authors examine primary prevention trials and population interventions. They believe that there is no evidence to support population changes in blood cholesterol and ascribe the opposite opinion to wishful thinking.
19.
RossouwJELewisBRifkindBM: The value of lowering cholesterol after myocardial infarction. N Engl J Med1990, 323:1112–1119. This review deals with secondary prevention by diet and drugs; it concludes that cholesterol-lowering should be pursued actively in most patients with coronary disease.
20.
MuldoonMFManuckSBMatthewsKA: Lowering cholesterol concentrations and mortality: A quantitative review of primary prevention trials. BMJ1990, 301:309–314. The authors review primary prevention trials using diet or drugs (considered together and separately). They show an association between cholesterol-lowering and death not related to illness and recommend a cautious approach to population-based interventions.
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HolmeI: An analysis of randomized trials evaluating the effect of cholesterol reduction on total mortality and coronary heart disease incidence. Circulation1990, 82:1916–1924. Holme reviews primary and secondary prevention trials of diet and drugs. He considers that cholesterol reduction lowers CHD incidence; an effect on total mortality requires a reduction of more than 8% and is more evident in secondary prevention.
22.
MuldoonMFManuckSBMatthewsKA: Mortality experience in cholesterol-reduction trials [letter]. N Engl J Med1991, 324:922–923. This letter summarizes visually the effects on mortality of lowering cholesterol by diet or drugs. In both primary and secondary prevention trials total mortality has been unaffected owing to a rise in deaths from other causes.
23.
SmithGDPekkanenJ: Should there be a moratorium on the use of cholesterol lowering drugs? BMJ1992, 304:431–434. This review considers primary prevention; it examines diet and drug trials separately and includes a non-randomized crossover trial. It suggests that adverse effects on non-CHD mortality are restricted to drug trials.
24.
SmithGDSongFSheldinTA: Cholesterol lowering and mortality: The importance of considering initial level of risk. BMJ1993, 306:1367–1373. Primary and secondary prevention trials are reviewed; diet and drug trials are considered together and separately. The authors conclude that excess non-CHD risk is a feature of drug trials, and that overall benefit depends on initial level of risk.
25.
LawMRWaldNJThompsonSG: By how much and how quickly does reduction in serum cholesterol concentration lower risk of ischaemic heart disease? BMJ1994, 308:367–372. A review of 10 large cohort studies, three ecological studies and 28 randomized trials advocates population measures to reduce serum cholesterol. A substantial reduction in CHD incidence is attainable by dietary change and would probably be similar in men and women.
26.
LawMRThompsonSGWaldNJ: Assessing possible hazards * of reducing serum cholesterol. BMJ1994, 308:373–379. The authors review 10 large cohort studies, two ecological studies and 28 randomized trials. They conclude that the only adverse effect of a low serum cholesterol level is an increased risk of haemorrhagic stroke.
27.
MorganREPalinkasLABarrett-ConnorELWingardDL: Plasma cholesterol and depressive symptoms in older men. Lancet1993, 341:75–79. Low plasma cholesterol was associated with depressive symptoms in older men after allowing for age, health status, chronic illness, medication, exercise, weight loss, and change in cholesterol level over the previous 13 years.
28.
LindbergGRastamLGullbergBEklundGA: Low serum cholesterol concentrations and short term mortality from injuries in men and women. BMJ1992, 305:277–279. A cohort study showed a strong negative relationship in men (but not in women) between serum cholesterol and mortality from injury and particularly suicide.
29.
KushiLHLewRAStareFJEllisonCRel LozyMBourkeG: Diet and 20-year mortality from coronary heart disease: The Ireland-Boston Diet-Heart Study. N Engl J Med1985, 312:811–818. A cohort study showed that CHD mortality was related to Keys and Hegsted scores of dietary fat intake after adjustment for other risk factors. Other similar studies are reviewed.
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JacobsDBlackburnHHigginsMReedDIsoHMcMillanG: Report of the conference on low blood cholesterol: Mortality associations. Circulation1992, 86:1046–1060. A meta-analysis of cohort studies shows that serum cholesterol has a U-shaped relationship with total mortality in men and no relationship in women, owing to the combination of a positive association with CHD death and a negative association with certain other deaths. Results are presented and discussed in some detail; the explanation of the adverse associations remains obscure.
31.
GottoAM: Cholesterol intake and serum cholesterol level. N Engl J Med1991, 324:912–913. This editorial reviews individual variation in response to cholesterol intake and draws attention to adaptive mechanisms.
32.
Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults: Summary of the second report of the National Cholesterol Education Program (NCEP) Expert Panel in Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel II). JAMA1993, 269:3015–3023. The Expert Panel revises its previous recommendations, placing a greater emphasis on CHD risk (existing disease and age) as a guide to type and intensity of cholesterol-reducing treatment, and on the value of exercise and weight loss.
33.
HulleySBWalshJMNewmanTB: Health policy on blood cholesterol: Time to change directions. Circulation1992, 86:1026–1029. This editorial considers the implications of recent work for national policies. It advocates restricting cholesterol screening and intervention to the minority for whom benefit outweighs harm: Those with a very high risk of CHD death.
