Report of the Conference on Low Blood Cholesterol: Mortality Associations

Enthusiasm misplaced? Revisiting cholesterol screening

Nursing journals have not reflected the abundant literature criticizing the National Cholesterol Education Program's goal to screen every adult American's cholesterol levels. Because this goal affects every nurse in professional, economic, and personal ways, it behooves nurses to consider the intensive debate that frames the benefits claimed for cholesterol screening. Issues raised by the debate may give nurses reason to question the program's goals. Once acquainted with inherent epidemiologic, methodologic, cost, and public policy issues, nurses may conclude there is insufficient scientific evidence to warrant cholesterol screening for the entire adult population. Rather, cholesterol screening may best be reserved for the relatively few Americans most likely to benefit from both screening and subsequent treatment.

Low serum cholesterol increases the risk of noncardiovascular events: an antagonist viewpoint

Considerable debate concerning the apparent association of low serum cholesterol levels with enhanced noncardiovascular disease mortality has been aired in both scientific and lay publications within the past year. This debate has resulted in some medical experts calling for a moratorium on efforts to reduce serum cholesterol, particularly with drugs, and for a more conservative approach to screening and modifying cholesterol levels for the primary prevention of coronary heart disease (CHD). Observational studies, including the Framingham Heart Study, the Multiple Risk Factor Intervention Trial, the Whitehall Study, and the International Collaborative Group, have not substantiated a cause and effect relationship between "naturally" occurring low serum cholesterol and noncardiovascular disease mortality, such as cancer. Intervention trials designed to lower high serum cholesterol levels by diet and drugs have also not been conclusively shown to produce excess harm that offsets the benefit of reduced CHD events. Several primary and secondary CHD prevention trials, with sufficient numbers of subjects to provide the statistical power to detect potential detrimental effects of lowering cholesterol levels, are currently in progress and will be very helpful in resolving the concern about noncardiovascular disease mortality.

Dyslipidemia and coronary artery disease

Genetically determined and metabolically induced disturbances in lipid metabolism, as manifested in several types of dyslipidemia, have been shown to be causally related to the development of coronary artery disease (CAD). A diversity of clinical and angiographic studies has been made to evaluate the linkage between plasma lipid-control therapy in the development of initial and recurrent cardiovascular events. The plan of treatment invariably begins with a low-fat, low-cholesterol diet before initiation of drug therapy. However, many patients have difficulty in adhering to the low-fat diet. Fortunately, metabolic studies show that foods which contain fats rich in stearic (saturated) and oleic (monounsaturated) fatty acids may be given in limited amounts to boost patients' compliance to a low-fat diet and to prevent their blood lipids from rising to abnormal levels. A bile acid sequestrant (cholestyramine or colestipol) is the first-line drug for control of hypercholesterolemia. Either gemfibrozil or gemfibrozil plus niacin is prescribed to raise high-density lipoprotein (HDL) levels of CAD patients. Approval of two HMG CoA reductase inhibitors, pravastatin and simvastatin, by the FDA gives physicians the additional flexibility of employing a single or a combination drug therapy for optimal control of dyslipidemia. The association of low serum cholesterol level (< 160 mg/dl) with increase in noncardiac mortality has prompted health professionals to consider modifying the universal screening and treatment of serum cholesterol in children and young women and to use hypolipidemic drugs in patients judiciously.

Total cholesterol and suicidality in depression

There exists considerable controversy regarding an association between low total cholesterol and increased mortality from suicide. As suicide mortality is a crude marker for suicidal ideation and behavior, we investigated the association between total cholesterol and suicidality in a depressed sample. Ninety men and women meeting structured criteria for a major depressive episode of at least moderate severity participated in a study of predictors of treatment response. A three level variable codified the degree of suicidality in the previous month: no suicidal thoughts (39/90), suicidal ideation or plan (38/90), and a suicide attempt (13/90). There was a significant univariate association between lower cholesterol levels and increasing degrees of suicidality. In a multivariate analysis, this association was the only one that neared statistical significance (p = 0.068). Although it is premature to conclude that these variables are causally associated, data from a number of sources suggest that this association is worthy of further study.

Hypocholesterolemia and affective disorders

The authors' specific aim was to assess hypocholesterolemia in 203 patients hospitalized because of affective disorders (depression, bipolar disorder, and schizoaffective disorder) compared with 1,595 self-referred subjects in an urban supermarket screening and with 11,864 subjects in the National Health and Nutrition Examination Survey II, a national probability sample. Low plasma cholesterol concentrations (< 160 mg/dL) were much more common in patients with affective disorders (20%) than in urban supermarket screenees (4%, P < or = 0.001) or in the National Health and Nutrition Examination Survey II subjects (10%, P < or = 0.001). When paired with supermarket screenees by age and sex, patients with affective disorders had much lower plasma total cholesterol (P < or = 0.0002), low-density lipoprotein cholesterol (P < or = 0.001), and high-density lipoprotein cholesterol (P < or = 0.0001), and higher triglyceride concentrations (P < or = 0.03). Neither the severity of the affective disorders nor severity-age interactions were associated with plasma cholesterol concentrations (P > 0.1); age and plasma cholesterol were positively associated (P = 0.01). None of the psychoactive drugs had a significant independent association with the patients' low-density lipoprotein cholesterol. Plasma cholesterol in patients hospitalized with affective disorders is shifted markedly downward toward hypocholesterolemic concentrations (< 160 mg/dL). There is no evidence that low plasma cholesterol could cause or worsen affective disorders.

Serum total cholesterol and mortality in a Japanese population

Although the relation between serum total cholesterol and coronary heart disease is well established, the relation with mortality from non-coronary disease is controversial. Inverse relations of serum cholesterol with hemorrhagic stroke and cancer have stimulated the examination of cholesterol-non-coronary mortality associations. The population surveyed is 12,187 men and women aged 40-69 years living in Yao City, a suburb of Osaka, who undertook baseline examinations between 1975 and 1984 and had no history of stroke and coronary heart disease at baseline. The subjects were followed on average 8.9 years until the end of 1988 using systematic mortality surveillance. During the follow-up, there were 343 deaths, comprising 170 cancer deaths (International Classification of Death 9th edition: ICD-9, 140-239), 21 coronary heart disease deaths (ICD-9, 410-414), 67 other cardiovascular deaths (ICD-9, 390-458 excluding 410-414), and 85 non-cardiovascular, non-cancer deaths. There was a significant inverse association of serum cholesterol with total and cancer mortality for men, and no significant association for women. The cholesterol-disease association, although not significant, was positive for coronary heart disease and other cardiovascular disease deaths, and inverse for non-cardiovascular, non-cancer deaths in both sexes. The inverse association of serum cholesterol with total and cancer mortality for men remained significant after controlling for age, job classification, hypertension category, usual alcohol intake, cigarette smoking, and relative weight index.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Cholesterol and Coronary Heart Disease: Changing Perspectives

There has been much controversy concerning the value of efforts to reduce blood cholesterol levels. In this contribution, the risks and benefits of interventions are discussed. Lowering cholesterol level by drugs is not recommended except in a small minority of subjects at very high risk of coronary heart disease (CHD), since it causes an excess of non-CHD deaths. Dietary intervention, by contrast, is safe. However, for it to be effective it must be sufficiently vigorous to achieve a drop in blood cholesterol of at least 6%, though considerably more is preferable. This action should be part of a more general effort aimed at the prevention of all Western diseases based on changes in lifestyle.

Management of postmenopausal women who have hyperlipidemia

Dyslipoproteinemia is prevalent in women as well as in men. In both, its consequences of premature atherosclerosis and coronary artery disease (CAD) morbidity and mortality are common. Although clinical evidence of the benefits of cholesterol lowering is less abundant in women, it is not entirely absent. As in men, cholesterol lowering in women is associated with a decline in CAD risk and regression of coronary atherosclerosis.

Prevalence of coronary heart disease indicated by electrocardiogram abnormalities and risk factors in developing countries

A cross-sectional population survey was carried out in 15 population groups (ethnicity includes Melanesian, Polynesian, Micronesian, Asian Indian and Chinese) in 9 developing countries: Fiji, Nauru, Kiribati, Cook Island, Niue, Western Samoa, New Caledonia, Mauritius and China (Beijing) in 1978-1987. The total sample included 4594 men and 4988 women aged 35-59 years. The aim of study is to report the prevalence of coronary heart disease (CHD) as indicated by ECG Minnesota coding, and risk factor levels and to describe the individual and ecological relationship between CHD prevalence and CHD risk factors among different ethnic groups in developing countries. Mauritians had the highest prevalence of CHD of these countries. Total serum cholesterol concentration and the prevalence of CHD were higher in Mauritius Chinese than in Beijing Chinese. Mean total cholesterol was lower than or equal to 5.2 mmol/l (200 mg/dl) in all population groups, except in Mauritians. Hypertensive subjects in most populations had a low cholesterol concentration. The prevalence of hypertension varied from 7 to 35% and mean body mass index (BMI) from 22.9 to 37.0 kg/m2. Smoking was more common in men (36-82%) than women (0.8-65%). Multiple logistic regression analysis using individuals as a unit of analysis showed that cholesterol and systolic blood pressure were significant independent predictors of CHD prevalence. When fasting or 2 hr post-load blood glucose was included in the model total cholesterol was no longer significant in men but remained significant in women. Ecological analysis using populations as units of analysis showed that the combination of several CHD risk factors could explain about 90% of the interpopulations variance of the CHD prevalence in women. The best models were those where 2 hr post-load glucose was included. Our study has demonstrated that the total cholesterol concentration of the population was consistent with the prevalence of CHD in the population. A considerable proportion of the variation in CHD prevalence across populations in developing countries can be explained by well-known risk factors. These data support the concept that retaining traditional balanced dietary habits and limiting salt intake together with avoiding smoking use are important activities for the prevention of cardiovascular disease (CVD) in developing countries.

Diet and health: what should we eat?

Many recent studies have implicated dietary factors in the cause and prevention of important diseases, including cancer, coronary heart disease, birth defects, and cataracts. There is strong evidence that vegetables and fruits protect against these diseases; however, the active constituents are incompletely identified. Whether fat per se is a major cause of disease is a question still under debate, although saturated and partially hydrogenated fats probably increase the risk of coronary heart disease. One clear conclusion from existing epidemiologic evidence is that many individuals in the United States have suboptimal diets and that the potential for disease prevention by improved nutrition is substantial.

Prevention and regression of coronary atherosclerosis. Is it safe and efficacious therapy?

OBJECTIVE

Atherosclerotic coronary heart disease (CHD) continues to be the dominant disease in Western society. A large body of evidence directly linking serum cholesterol levels and CHD risk has stimulated population treatment strategies designed to reduce cholesterol and CHD risk. Data indicating a relation between low cholesterol and non-CHD risk have, however, suggested that cholesterol reduction may not always be desirable. The primary goal of this evaluative review of the available evidence was to answer the following question: Is prevention/regression therapy for CHD safe and effective?

DATA SOURCES

Three lines of evidence were reviewed: epidemiologic studies; primary and secondary prevention trials with clinical end points; and secondary prevention trials with quantitative coronary angiography as a surrogate end point for clinical CHD.

STUDY SELECTION

Original studies and meta-analyses were reviewed. The principal selection criteria for the epidemiologic studies were large size and prolonged follow-up; for the trials, randomization and viable clinical (CHD events, CHD mortality, total mortality) or angiographic end points.

DATA EXTRACTION

The data were initially extracted by a single reviewer using common qualitative guidelines. The data were then evaluated by all authors acting as a data interpretation team.

DATA SYNTHESIS

Overall, the epidemiologic data revealed excess risk of fatal and nonfatal CHD events was directly related to total cholesterol and low-density lipoprotein (LDL) cholesterol levels, for both men and women and for both younger (< 65 years) and older (> or = 65 years) patients, over a wide range of serum cholesterol levels. The predictive value was higher in younger men than older men and women, although part of this quantitative interaction may be due to fewer studies, with fewer end points, in the older and female populations. The CHD events and CHD mortality, but not total mortality, were consistently reduced in trials of cholesterol-lowering therapy. The regression trials, predominantly in CHD patients with high cholesterol values (mean 7.1 mmol/L), demonstrated improvement in angiographic atherosclerosis in every study. The evidence for elevated risk of non-CHD death at very low levels of cholesterol is uncertain and controversial. The most likely possibilities for this apparent relationship are unknown confounding variables and the play of chance.

CONCLUSIONS

Serum cholesterol levels are directly associated with CHD risk, and there is no threshold level below which there is no risk. Reduction of high serum cholesterol levels reduces CHD risk. Whether lipid-lowering and adjunctive antiatherosclerotic therapies are effective and safe in the majority of CHD patients who have desirable or borderline cholesterol levels remains undetermined.

Assessing possible hazards of reducing serum cholesterol

OBJECTIVE

To assess whether low serum cholesterol concentration increases mortality from any cause.

DESIGN

Systematic review of published data on mortality from causes other than ischaemic heart disease derived from the 10 largest cohort studies, two international studies, and 28 randomised trials, supplemented by unpublished data on causes of death obtained when necessary.

MAIN OUTCOME MEASURES

Excess cause specific mortality associated with low or lowered serum cholesterol concentration.

RESULTS

The only cause of death attributable to low serum cholesterol concentration was haemorrhagic stroke. The excess risk was associated only with concentrations below about 5 mmol/l (relative risk 1.9, 95% confidence interval 1.4 to 2.5), affecting about 6% of people in Western populations. For noncirculatory causes of death there was a pronounced difference between cohort studies of employed men, likely to be healthy at recruitment, and cohort studies of subjects in community settings, necessarily including some with existing disease. The employed cohorts showed no excess mortality. The community cohorts showed associations between low cholesterol concentration and lung cancer, haemopoietic cancers, suicide, chronic bronchitis, and chronic liver and bowel disease; these were most satisfactorily explained by early disease or by factors that cause the disease lowering serum cholesterol concentration (depression causes suicide and lowers cholesterol concentration, for example). In the randomised trials nine deaths (from a total of 687 deaths not due to ischaemic heart disease in treated subjects) were attributed to known adverse effects of the specific treatments, but otherwise there was no evidence of an increased mortality from any cause arising from reduction in cholesterol concentration.

CONCLUSIONS

There is no evidence that low or reduced serum cholesterol concentration increases mortality from any cause other than haemorrhagic stroke. This risk affects only those people with a very low concentration and even in these will be outweighed by the benefits from the low risk of ischaemic heart disease.

Low cholesterol and risk of non-coronary mortality

Based on a systematic review of over 20 cohort studies, a clear association exists, for both men and women, between particularly low cholesterol levels and the rate of non-coronary mortality. The excess in women appears mainly confined to non-cancer causes, particularly respiratory and digestive diseases, while there is also an excess of deaths from cancer seen in men with low cholesterol levels. Higher mortality rates from trauma, haemorrhagic stroke and cirrhosis have also been observed. Much of this association is known to be as a consequence of the disease with a fall in cholesterol levels seen after developing a variety of inflammatory diseases. However, the excess risk of non-coronary heart disease deaths is still apparent by excluding deaths within five years suggesting that effect-cause is not the only explanation. Confounding still remains the most likely explanation for the association with an underlying chronic disease or risk factor causing both the low cholesterol and the fatal event. However, there is still the possibility that some of the increased risk is due to the low cholesterol. This makes it important that appropriately controlled trials of both drug and dietary interventions demonstrate net clinical benefit among those with low levels of coronary risk before cholesterol-lowering strategies are adopted more widely in these groups.

Is knowing your cholesterol number harmful?

To examine the potential adverse psychological effects of screening for hypercholesterolemia, 287 men working at a motor-car assembly or steel-making plant who were ultimately diagnosed as having hypercholesterolemia and 236 randomly selected normal cholesterol controls from the same plants completed psychological questionnaires at the initial screen and 1-year later. At baseline and before diagnosis, hypercholesterolemic men scored higher on mental health and lower on negative affect than controls (p values < 0.05). One year later no adverse changes on the psychological measures were found irrespective of the type of follow-up care that they were randomly assigned to receive. Surprisingly only about half of the hypercholesterolemic men believed they had hypercholesterolemia at follow-up despite being told otherwise. Baseline scores of those who did not accept the label (n = 122) [classified as deniers] were higher on measures of positive affect and lower on measures of negative effect than those of hypercholesterolemic men who accepted the disease label (n = 73) (p values < 0.05). Moreover they held more negative attitudes towards dietary change at baseline (p < 0.03), made fewer dietary changes (p values < 0.05), and had a lesser change in total cholesterol. We conclude that a hypercholesterolemia detection and treatment program conducted in a working adult population had no adverse psychological consequences. It did, however, reveal a large subset of hypercholesterolemic men who did not accept the label despite being told they had this problem. Denial was a significant barrier to health behaviour change and may represent a maladaptive coping style for men at risk of cardiovascular disease. High cholesterol appears to be associated with better mental health and those who deny having hypercholesterolemia have the best mental health. The multifarious relationship between cholesterol, mental health, and denial deserves further study.

The Helsinki Heart Study: an 8.5-year safety and mortality follow-up

OBJECTIVES

Earlier monitoring of all symptoms, hospital admissions, cancer diagnoses and causes of death during gemfibrozil treatment had raised some suspicions which called for further follow-up.

DESIGN

Close monitoring of selected, potentially adverse events amongst treated subjects after a placebo-controlled trial and comparing occurrences to those in various untreated groups.

SETTING

All participants of the Helsinki Heart Study (a controlled, 5-year, multi-clinic coronary heart disease (CHD) primary prevention trial with gemfibrozil and placebo) were offered gemfibrozil treatment and twice yearly follow-up for 3.5 years. Untreated groups in the source population and national cancer statistics were utilized in comparisons.

SUBJECTS

Of the 2046 dyslipidaemic men initially randomized to gemfibrozil, 2002 survivors entered the 3.5-year follow-up; of the 2035 initial placebo men, 1992 continued to be monitored.

INTERVENTIONS

Gemfibrozil was chosen for the follow-up by 66.3% of the gemfibrozil-treated and 68.5% of the placebo-treated men.

MAIN OUTCOME MEASURES

Gastrointestinal symptoms, surgery, strokes, cancer incidence, mortality by cause.

RESULTS

Gastrointestinal symptoms remained more common in the original gemfibrozil group. After 8.5 years strokes numbered 32 (gemfibrozil) vs. 37 (placebo), violent deaths 16 vs. 14, and cancers 51 in both groups. Total mortality was equal during the original 5 years, but higher in the gemfibrozil group post-trial, leading to an 8.5 year mortality of 101 vs. placebo 83 (P = 0.19). This was mainly a result of higher cancer mortality in the gemfibrozil (30) than the placebo group (18, P = 0.08). An additional 18-month post-study registry follow-up disclosed 13 placebo and five gemfibrozil cancer deaths, altering the cancer mortality to gemfibrozil 35 vs. placebo 31 at 10 years.

CONCLUSIONS

The most plausible explanation for the discrepancy between cancer incidence and cancer-specific mortality, based mainly on comparison with untreated groups, is delayed diagnosis. The increased cancer and total mortality is most probably due to chance, based on the later reversal of trends.

Dyslipoproteinemia in women and the elderly

Major risk factors predict coronary risk in both women and men. It is inadvisable and unwarranted to suggest that women be excluded from cholesterol screening. In fact, what evidence is available suggests that women, similar to men, benefit from cholesterol lowering. This is not an insignificant issue. Women, similar to men, die mostly of coronary atherosclerosis, although atherosclerotic death in women occurs 5 to 10 years later than in men. There are some risk factors that are unique in women. LDL-c levels may be less predictive of risk in women than in men; HDL-c levels may be more predictive. Triglycerides are a stronger predictor of risk in women than in men. Finally, diabetes is a major risk factor in women and almost eliminates the differences in risk seen in comparing nondiabetic men and women. Exogenous gonadal hormones, both in the form of OCs and HRT, have the potential to influence coronary risk in women. In premenopausal women, use of OCs is associated with increased risk of coronary disease in women who smoke, particularly in women older than age 35. In postmenopausal women, estrogen use is generally associated with protection against coronary disease. These results may be in part due to favorable effects on circulating lipoproteins but may as well be related to the protective effects of estrogen on the arterial wall. Definitive recommendations about the use of estrogen in postmenopausal women for the primary prevention of coronary disease await the completion of clinical trials of estrogen alone and in combination with progestins. Cholesterol and its lipoprotein subfractions continue to be predictors of both morbidity and mortality in older populations. The value of cholesterol-altering therapy in older individuals is not as well established in clinical trials as in middle-aged men. Nevertheless, there is good reason to believe that the results from both primary and secondary prevention studies in younger individuals can readily be extrapolated to older individuals. In particular, individuals with symptomatic coronary disease but a relatively good prognosis should be offered the same benefits from secondary prevention as younger individuals. Thus, although data are more limited in women and the elderly than in middle-aged men, there is good reason to believe that cholesterol interventions are likely to be effective, particularly in postmenopausal women and in older individuals with established coronary disease. To withhold therapy based simply on gender or chronologic age is a mistake.

Lowering cholesterol for prevention of coronary heart disease--problems and perspectives

The evidence for aggressive treatment of severe hypercholesterolemia in men in order to reduce the development on a primary basis of the incidence of coronary heart disease is strong; the main benefit is reduction of morbidity. Extrapolation to women or to the management of mild hypercholesterolemia in either gender is not supported by facts. The value of reducing hypercholesterolemia in the young and in the elderly has not been tested. None of the primary or secondary prevention trials have reduced all-cause mortality. There is an inverse relation between cholesterol levels and noncardiovascular disease. The possibility that reducing mild to moderate elevation of cholesterol might be harmful to some people remains unanswered.

Treating mild hypercholesterolemia in the absence of overt cardiovascular disease: if, when, and why?

Cohort data define a range of cholesterol concentrations (160-200 mg/dl), which is desirable in terms of public health. Cholesterol-lowering treatment leading to a serum cholesterol in this range is favorable for coronary heart disease prevention and safe in terms of noncardiovascular mortality. In individuals with moderate cholesterol elevation and without other coronary risk factors, the physician should encourage a healthy lifestyle and give prudent nutritional advice. Detection of asymptomatic cardiovascular disease by noninvasive methods might be used to identify individuals with mild hypercholesterolemia, but nevertheless at high risk for ischemic accidents. The aim of lipid-lowering treatment is to improve life expectancy through reduction of a major cause of premature death.

Cholesterol confusion in primary prevention of coronary artery disease

Despite the impressive relation between an increased blood cholesterol and increased mortality from coronary artery disease and despite the persuasive results of cholesterol-lowering trials in secondary prevention, there are increasing reservations about the wisdom of lowering moderately raised blood cholesterol levels in patients who have no symptoms of coronary artery disease. In particular, there are important differences between total mortality and cardiovascular mortality, and between relative and absolute risks. A policy that may be practiced by clinical cardiologists is proposed. In essence, each patient should be assessed for all the chief cardiovascular risk factors in that particular individual. Primary prevention by cholesterol reduction in the absence of symptoms of coronary artery disease requires very careful judgement and should only be undertaken when there is good evidence that the risk of coronary artery disease can be reduced in absolute terms. For primary prevention to be effective requires that the whole gamut of coronary risk factors should be addressed.

Effects of pravastatin in patients with serum total cholesterol levels from 5.2 to 7.8 mmol/liter (200 to 300 mg/dl) plus two additional atherosclerotic risk factors. The Pravastatin Multinational Study Group for Cardiac Risk Patients

This placebo-controlled, multinational study evaluated the use of pravastatin in 1,062 patients with hypercholesterolemia (serum total cholesterol concentrations of 5.2 to 7.8 mmol/liter [200 to 300 mg/dl]) and > or = 2 additional risk factors for atherosclerotic coronary artery disease. Efficacy and safety analyses were performed on the initial 26-week, randomized, double-blind, placebo-controlled period; further safety analyses were conducted on the subsequent 52 weeks, which included an additional 26-week double-blind phase permitting other lipid-lowering agents and a final 26-week open-label period. At offweeks, pravastatin at a dose of 20 mg once daily at bedtime significantly lowered serum low-density lipoprotein cholesterol 26% (4.7 to 3.5 mmol/liter [182 to 135 mg/dl]), total cholesterol 19% (6.8 to 5.6 mmol/liter [263 to 217 mg/dl]) and triglycerides 12% (1.8 to 1.6 mmol/liter [159 to 142 mg/dl]) (p < 0.001 compared with placebo) and significantly raised serum high-density lipoprotein cholesterol 7% (1.1 to 1.2 mmol/liter [43 to 46 mg/dl]) (p < 0.001 compared with placebo). Efficacy of pravastatin was maintained at 26 weeks, and during this initial period there were significantly more serious cardiovascular adverse events in the placebo group (13 events, 2.4%) than in the pravastatin group (1 event, 0.2%) (p < 0.001). Six myocardial infarctions, 5 cases of unstable angina and 1 sudden cardiac death occurred in the placebo group, compared with none of these events in the pravastatin group. In this study, pravastatin produced beneficial effects on serum lipids and was associated with a reduction in the incidence of serious cardiovascular adverse events.

Modifying serum lipids to prevent coronary heart disease: do we have a consensus?

Despite the importance of hyperlipidemia as an independent coronary risk factor and the positive results of recent lipid intervention trials to prevent coronary disease, there remain many unanswered questions regarding the benefits and risks of treating hyperlipidemia. Critical review of epidemiologic studies and clinical trials suggest that the benefits of cholesterol reduction may vary depending on the patient's age, sex, and the presence of other coronary risk factors. Furthermore, one must recognize that there is a small but consistent increase in noncoronary deaths among patients receiving cholesterol-lowering medications that remains unexplained but requires further evaluation. These data underscore the importance of weighing both the risks and benefits of modifying serum lipids. Accordingly, careful evaluation of the underlying risk of developing coronary disease and the potential long-term benefits of intervention are necessary to identify appropriate high-risk patients for treatment among whom the predicted benefits will outweigh the risks.

Does low cholesterol cause death?

Data linking low cholesterol with excess mortality have been gathered from both observational and clinical trials. The data are probably unrelated, as the levels of total cholesterol associated with excess mortality in observational studies are well below 160 mg/dl (4.1 mmol/l), whereas the levels achieved in clinical trials average around 230 mg/dl (5.9 mmol/l). Likely explanations of the association are that low cholesterol is a consequence of disease or is a confounder associated with other variables. The authors assess the relevance of the data to public health policy and medical practice. They conclude that evidence suggesting low cholesterol is a cause of excess mortality currently lacks breadth and rigor, and find no basis for changing cholesterol-management guidelines.

Cholesterol lowering, low cholesterol, and mortality

Cholesterol lowering in both primary and secondary prevention has been clearly demonstrated to lower coronary morbidity and, in secondary prevention, to lower coronary mortality as well. Putative dangers of cholesterol lowering remain unproven. Population studies linking low cholesterol to noncoronary mortalities do not demonstrate cause-and-effect relations. In fact, based on current studies, the opposite is more likely to be the case. Neither gender nor age should automatically exclude persons from cholesterol screening. Drug intervention, however, should be used conservatively, particularly in young adults and the elderly. Drugs should be used only after diet and lifestyle interventions have failed. The evidence linking high blood cholesterol to coronary atherosclerosis and cholesterol lowering to its prevention is broad-based and definitive. Concerns about cholesterol lowering and spontaneously low cholesterols should be pursued but should not interfere with the implementation of current public policies to reduce the still heavy burden of atherosclerosis in Western society.

Low-density lipoprotein immunofluorescence at the site of renal injury in glomerulosclerosis: a potential pathogenetic role for lipids in renal disease

The role of lipids in the genesis of renal disease has received increased attention. We describe the presence of anti-low-density lipoprotein immunofluorescence at the site of renal injury found by light microscopy. This may offer immunohistologic evidence for a potential role of this atherogenic lipid in the genesis of renal disease and glomerulosclerosis. Furthermore, we describe the contribution of cholesterol in early renal disease and markers for malnutrition in the dialytic management of end-stage renal disease. Interventional strategies, including vasoactive agents present and future, are presented.

Contraception and dyslipidemia

The risks of cardiovascular disease associated with dyslipidemia differ in women and men, being more strongly associated with triglyceride/high-density lipoprotein in middle-aged women than in men. Although the incidence of heart disease is lower in women because they live longer, over a lifetime, cardiovascular disease in women is equal to that in men, with the greatest incidence after age 65 years. Major coronary events are rare among reproductive-age women who use oral contraceptives and are related to the concomitant effects of age, smoking, diabetes, hypertension, and obesity. Low estrogen-progestin dose oral contraceptives appear not to promote cardiovascular disease and can be used in women with controlled cholesterol elevations. Alternative contraceptive measures should be considered for patients with severe uncontrolled hypercholesterolemia or a lipid disorder that carries a high risk of coronary heart disease. In these conditions, thrombotic propensity associated with supraphysiologic doses of estrogen in oral contraceptives might accelerate coronary thrombosis should an arteriosclerotic plaque rupture. Treatment of hypercholesterolemia should follow the guidelines of the National Cholesterol Education Program and emphasize hygienic measures. Contraceptive selection in hyperlipidemic patients should reflect a balance between the risks--and their management--of developing cardiovascular disease versus the risks of pregnancy.

Prolonged infection with hepatitis B virus and association between low blood cholesterol concentration and liver cancer

OBJECTIVE

To determine whether prolonged infection with hepatitis B virus is associated with a lower blood cholesterol concentration.

DESIGN

Cross sectional study.

SETTING

81 villages in rural China with a high prevalence of chronic infection with hepatitis B virus.

SUBJECTS

1556 apparently healthy men aged 35-64 years, randomly selected.

MAIN OUTCOME MEASURES

Hepatitis B virus carrier state; plasma concentrations of cholesterol, apolipoprotein B, and apolipoprotein A I.

RESULTS

238 (15%) of the men were positive for hepatitis B surface antigen, indicating that they were chronic carriers. Plasma concentration of cholesterol was 4.2% (0.11 mmol/l) lower among carriers (that is, positive for hepatitis B surface antigen) than among non-carriers (95% confidence interval 0.6% to 8.0% (0.01 to 0.21 mmol/l), p < 0.05), and apolipoprotein B concentration was 7.0% (0.036 g/l) lower (2.8% to 11.2% (0.014 to 0.058 g/l), p < 0.001). In contrast, no association was observed between plasma concentrations of cholesterol or apolipoprotein and hepatitis B that had been eradicated (that is, patient positive for hepatitis B core antibody but negative for hepatitis B surface antigen).

CONCLUSIONS

Chronic hepatitis B virus infection, which usually starts in early childhood in China, seems to lead not only to a greatly increased risk of death from liver disease but also to a somewhat lower cholesterol concentration in adulthood. This common cause produces an inverse association between cholesterol concentration and risk of death from liver cancer or from other chronic liver diseases.