Serum cholesterol, other risk factors, and cardiovascular disease in a Japanese cohort

Associations between trace level thallium and multiple health effects in rural areas: Chinese Exposure and Response Mapping Program (CERMP)

Thallium (Tl) is a cumulative high toxicant in the environment, but few studies have investigated the comprehensive health effects underlying chronic Tl exposure at trace levels. This study aims to evaluate the liver, kidney, lung and other potential health effects associated with chronic Tl exposure at trace levels in rural areas of China. Urinary Tl concentrations of 2883 adults from rural areas of 12 provinces in China were measured and 2363 participants were involved in the final analysis. Indicators of liver and kidney functions in the serum, as well as the lung function indicators, were determined in the participants. General linear regression and restricted cubic spline regression were combined to study the associations between urinary Tl and health indicators or outcomes. In this study, the detected rate of Tl in the urine of the participants was 97.28 %. When the urinary Tl concentration was ranged at the fourth quintile, the risk of having liver function disorder was 70 % higher [Odds ratio (OR) = 1.70 (95 % confidence intervals (CI): 1.30, 2.22)] in all the participants, whereas the farmers were more likely to have the disorder [OR = 2.08 (95 % CI: 1.49, 2.92)] than the non-farmers [OR = 1.20 (95 % CI: 0.77, 1.88)]. Nonlinear associations between most of the liver health indicators and urinary Tl were identified, of which serum bilirubin was strongly associated with the elevation of urinary Tl when its concentration was >0.40 μg/g creatinine. Besides, urinary Tl was negatively associated with lung health indicators. Our study proposes the safety re-assessment of the current exposure level of Tl in the environment, especially in rural areas of China.

Clinical characteristics and risk factors of pulmonary hypertension associated with chronic respiratory diseases: a retrospective study

BACKGROUND

Chronic respiratory disease-associated pulmonary hypertension (PH) is an important subtype of PH, which lacks clinical epidemiological data in China.

METHODS

Six hundred and ninety three patients hospitalized from 2010 to 2013 were classified by echocardiography according to pulmonary arterial systolic pressure (PASP): mild (36≤ PASP <50 mmHg); moderate (50≤ PASP <70 mmHg) and severe (PASP ≥70 mmHg).

RESULTS

Dyspnea (93.51%) was the most common symptom. Hemoptysis observed in the severe group (6.42%) was significantly higher than the other two groups (P<0.05). COPD (78.35%), lung bullae (44.16%), tuberculosis (including obsolete pulmonary tuberculosis) (38.82%), and bronchiectasis (30.45%) were frequently present. Mild group occupied the highest proportion (84.7%) in COPD, while severe group occupied the highest proportion (19.3%) in pulmonary embolism (P<0.01). Age, partial pressure of oxygen (PaO2), hematocrit (HCT), partial pressure of carbon dioxide (PaCO2), increase of N-terminal pro brain natriuretic peptide (NT-proBNP) and right ventricular (RV) diameter (>20 mm) were associated with moderate-to-severe PH, while RV [odds ratio (OR) =3.53, 95% CI, 2.17-5.74], NT-proBNP (OR=2.44, 95% CI, 1.51-3.95), HCT (OR=1.03, 95% CI, 1.00-1.07) and PaCO2 (OR=1.01, 95% CI, 1.00-1.03) were independent risk factors.

CONCLUSIONS

PH related to respiratory diseases is mostly mild to moderate, and the severity is associated with the category of respiratory disease. Increased HCT can be an independent risk factor for PH related to chronic respiratory diseases.

Sub-optimal achievement of guideline-derived lipid goals in management of diabetes patients with atherosclerotic cardiovascular disease, despite high use of evidence-based therapies

Guidelines recommend aggressive goals for lipid and blood pressure reduction for high risk patients with diabetes mellitus and atherosclerotic coronary disease. However, it remains unclear how many patients achieve treatment goals versus the number of people merely placed on treatment. We conducted an observational study in an academic cardiology clinic. A total of 926 patients with atherosclerotic cardiovascular disease and concomitant diabetes mellitus met criteria. Mean age was 68.4 ± 10.2, 65.6% were male, and 86.8% were Caucasian. By the last visit a high percentage of patients were receiving recommended medications. Mean LDL-cholesterol achieved was 80.4 mg/dl with 40.9% reaching ≤ 70 mg/dl, and 61.7% reaching SBP ≤ 130 mmHg. Many patients with diabetes mellitus and atherosclerotic cardiovascular disease are prescribed recommended medications; however, few achieve guidelines-specified therapeutic goals for LDL-cholesterol and blood pressure. Studies evaluating performance improvement should include percentage of patients reaching treatment goals. Mechanisms underlying the treatment gap need to be identified and addressed.

Randomized trial of the effects of cholesterol-lowering with simvastatin on peripheral vascular and other major vascular outcomes in 20,536 people with peripheral arterial disease and other high-risk conditions

OBJECTIVES

The Heart Protection Study (HPS) provides an opportunity to assess directly the effects of cholesterol-lowering therapy on major vascular events (defined as myocardial infarction, coronary death, stroke, or revascularization) in patients with peripheral arterial disease (PAD). In addition, the effects on peripheral vascular events (ie, non-coronary revascularization, aneurysm repairs, major amputations or PAD deaths) can be assessed.

METHODS

6748 UK adults with PAD and 13,788 other high-risk participants were randomly allocated to receive 40 mg simvastatin daily or matching placebo, yielding an average LDL cholesterol difference of 1.0 mmol/L (39 mg/dL) during a mean of 5 years.

RESULTS

For participants with PAD, allocation to simvastatin was associated with a highly significant 22% (95% CI 15-29) relative reduction in the rate of first major vascular event following randomisation (895 [26.4%] simvastatin-allocated vs 1101 [32.7%] placebo-allocated; P < .0001), which was similar to that seen among the other high-risk participants. The absolute reduction in first major vascular event was 63 (SE 11) per 1000 patients with PAD and 50 (SE 7) per 1000 without pre-existing PAD. Overall, among all participants, there was a 16% (5-25) relative reduction in the rate of first peripheral vascular event following randomisation (479 [4.7%] simvastatin vs 561 [5.5%] placebo), largely irrespective of baseline LDL cholesterol and other factors. This effect chiefly reflects a 20% (8-31) relative reduction in non-coronary revascularization procedures (334 [3.3%] vs 415 [4.0%]; P = .002).

CONCLUSION

HPS demonstrates the benefits of cholesterol-lowering statin therapy in patients with PAD, regardless of their presenting cholesterol levels and other presenting features. Allocation to 40 mg simvastatin daily reduces the rate of first major vascular events by about one-quarter, and that of peripheral vascular events by about one-sixth, with large absolute benefits seen in participants with PAD because of their high vascular risk. Consequently, statin therapy should be considered routinely for all patients with PAD.

An ezetimibe-policosanol combination has the potential to be an OTC agent that could dramatically lower LDL cholesterol without side effects

Although many risk factors influence atherogenesis, LDL appears to play a primary role in this process. In prospective epidemiology, coronary risk increases as LDL cholesterol increases, throughout the entire range of concentrations encountered in healthy humans. Coronary risk is minimal in individuals and populations whose serum cholesterol remains quite low throughout life. Thus, practical strategies for achieving large reductions of LDL cholesterol in the general population could have a dramatic impact on coronary mortality rates. Dietary measures have limited potential in this regard; modest restriction of saturated fat has a rather trivial effect on LDL cholesterol, and the very-low-fat quasi-vegan diets that do have a notable effect in this regard currently have little appeal to the majority of the population. With respect to pharmacotherapy, most available hypolipidemic agents with reasonably potent activity entail side effects or compliance difficulties that would render their use too expensive or impractical for population-wide application. However, two agents may have great potential in this regard: policosanol and ezetimibe. The former, a mixture of long-chain alcohols derived from sugar cane wax, has effects on serum lipids comparable to those of statins, and may work by down-regulating expression of HMG-CoA reductase. However, unlike statins, policosanol appears to be devoid of side effects or risks. Ezetimibe is a newly approved drug that is a potent and highly specific inhibitor of an intestinal sterol permease; in daily doses as low as 10 mg, it suppresses intestinal absorption of cholesterol and decreases serum LDL cholesterol by approximately 18%. No side effects have been seen in clinical doses, and the fact that its hypolipidemic activity is additive to that of statins has generated considerable interest. Both policosanol and ezetimibe can be administered once daily. Future studies should determine whether policosanol, like statins, interacts additively with ezetimibe. If so, it may be feasible someday to produce a tablet combining policosanol and ezetimibe that could reduce LDL cholesterol by about 40%, without side effects, and that could be recommended to virtually anyone whose LDL cholesterol levels were not already ideal.

Changes in flow-mediated dilatation, cytokines and carotid arterial stenosis during aggressive atorvastatin treatment in normocholesterolemic patients

BACKGROUND

Aggressive statin therapy to reduce low-density lipoprotein (LDL) cholesterol in patients with normal LDL-cholesterol levels reduces the incidence of future cardiovascular events and enhances atherosclerotic regression in the common carotid artery. We tried to quantify changes in flow-mediated dilatation (FMD), inflammatory cytokines, and the severity of carotid arterial stenosis, after aggressive statin administration to patients with normal LDL-cholesterol levels, and stroke or transient ischemic attack ipsilateral to carotid arterial stenosis.

METHODS

Twenty patients with at least a 50% reduction in the diameter of the carotid artery were studied. Atorvastatin 10 mg daily was prescribed for 4 months. Serial changes in the severity of carotid arterial stenosis, and brachial-artery FMD were evaluated by high-resolution ultrasound. Tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), interleukin-6 (IL-6), vascular cell adhesion molecule (VCAM), intracellular adhesion molecule (ICAM), soluble endothelin-1 (ET-1), and high-sensitivity C-reactive protein (hs-CRP), were measured before, and after 2 and 4 months of, atorvastatin treatment.

RESULTS

Atorvastatin significantly decreased plasma levels of total cholesterol and LDL-cholesterol after 1, 2 and 4 months of treatment (p < 0.01). FMD showed significant improvement after only 4 months (10.0% vs 6.8% at baseline; p = 0.019). The overall severity of carotid arterial lesions was not significantly reduced by atorvastatin. Changes in TNF-alpha, IL-1beta, IL-6 and ET-1 showed trends towards a progressive decline after atorvastatin, but none of the cytokines was reduced significantly. FMD did not correlate with the severity of carotid arterial stenosis, lipid profile, or cytokine levels.

CONCLUSION

Atorvastatin effectively reduced plasma concentrations of total cholesterol and LDL-cholesterol, and had beneficial effects on endothelial function, in Chinese patients with carotid arterial stenosis and normal LDL-cholesterol levels.

Cardiovascular outcomes among participants with diabetes in the recent large statin trials

PURPOSE OF REVIEW

Despite their increased cardiovascular risk and its continuous relationship with cholesterol, until recently only diabetic patients with marked dyslipidaemia were routinely offered lipid-lowering therapy. The secondary prevention statin trials led to more widespread cholesterol lowering in patients with coronary disease and diabetes. Here we review the results of recent randomized trials, which included substantial numbers of patients with diabetes and no vascular disease.

RECENT FINDINGS

The MRC/BHF Heart Protection Study included 5963 participants with diabetes, of whom 2912 had no history of vascular disease at baseline. Patients were randomized to 40 mg simvastatin daily or matching placebo for 5 years, which, on average, reduced LDL by 1.0 mmol/l compared with placebo. Highly significant reductions of about one-quarter in major vascular events were seen both overall and in different types of patient with diabetes, including those with average and below average lipid levels. Recent data from the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial and the Anglo-Scandinavian Cardiac Outcomes Trial support these findings and are consistent with these effects.

SUMMARY

Good quality, randomized trials including substantial numbers of patients with diabetes show that such patients obtain the same proportional benefit as other groups studied. Given their increased cardiovascular risk, these findings argue for a simple strategy of considering routine statin therapy for patients with type 2 diabetes and adult patients with type 1 diabetes, irrespective of lipid levels. As generic statins become available this could have a greater impact on the burden of cardiovascular disease in diabetes than restricted and targeted therapy.

Effects of cholesterol-lowering with simvastatin on stroke and other major vascular events in 20536 people with cerebrovascular disease or other high-risk conditions

BACKGROUND

Lower blood cholesterol concentrations have consistently been found to be strongly associated with lower risks of coronary disease but not with lower risks of stroke. Despite this observation, previous randomised trials had indicated that cholesterol-lowering statin therapy reduces the risk of stroke, but large-scale prospective confirmation has been needed.

METHODS

3280 adults with cerebrovascular disease, and an additional 17256 with other occlusive arterial disease or diabetes, were randomly allocated 40 mg simvastatin daily or matching placebo. Subgroup analyses were prespecified of first "major vascular event" (ie, non-fatal myocardial infarction or coronary death, stroke of any type, or any revascularisation procedure) in prior disease subcategories. Subsidiary outcomes included any stroke, and stroke sub-type. Comparisons are of all simvastatin-allocated versus all placebo-allocated participants (ie, "intention-to-treat"), which yielded an average difference in LDL cholesterol of 1.0 mmol/L (39 mg/dL) during the 5-year treatment period.

FINDINGS

Overall, there was a highly significant 25% (95% CI 15-34) proportional reduction in the first event rate for stroke (444 [4.3%] simvastatin vs 585 [5.7%] placebo; p<0.0001), reflecting a definite 28% (19-37) reduction in presumed ischaemic strokes (p<0.0001) and no apparent difference in strokes attributed to haemorrhage (51 [0.5%] vs 53 [0.5%]; rate ratio 0.95 [0.65-1.40]; p=0.8). In addition, simvastatin reduced the numbers having transient cerebral ischaemic attacks alone (2.0% vs 2.4%; p=0.02) or requiring carotid endarterectomy or angioplasty (0.4% vs 0.8%; p=0.0003). The reduction in stroke was not significant during the first year, but was already significant (p=0.0004) by the end of the second year. Among patients with pre-existing cerebrovascular disease there was no apparent reduction in the stroke rate, but there was a highly significant 20% (8-29) reduction in the rate of any major vascular event (406 [24.7%] vs 488 [29.8%]; p=0.001). The proportional reductions in stroke were about one-quarter in each of the other subcategories of participant studied, including: those with coronary disease or diabetes; those aged under or over 70 years at entry; and those presenting with different levels of blood pressure or lipids (even when the pretreatment LDL cholesterol was below 3.0 mmol/L [116 mg/dL]).

INTERPRETATION

Much larger numbers of people in the present study suffered a stroke than in any previous cholesterol-lowering trial. The results demonstrate that statin therapy rapidly reduces the incidence not only of coronary events but also of ischaemic strokes, with no apparent effect on cerebral haemorrhage, even among individuals who do not have high cholesterol concentrations. Allocation to 40 mg simvastatin daily reduced the rate of ischaemic strokes by about one-quarter and so, after making allowance for non-compliance in the trial, actual use of this regimen would probably reduce the stroke rate by about a third. HPS also provides definitive evidence that statin therapy is beneficial for people with pre-existing cerebrovascular disease, even if they do not already have manifest coronary disease.

Lipids and coronary heart disease in Asia

In Western countries, it has been shown that coronary heart disease (CHD) is related to high serum total cholesterol (TC) levels. In less developed continents such as Asia and Africa, serum lipid levels are low and CHD incidence is much lower as compared with Western countries. With growing urbanization and industrialization in Asia, it has been shown that there is a concomitant rise in the level of serum TC and with it a rise in CHD. In all the Asian countries, serum TC levels are also higher in the urban compared with the rural population. Singapore, the only Asian country which is 100% urbanized since 1980, showed a rise of serum TC similar to that seen in the US and UK from the 1950s to the 1980s followed thereafter by a fall. This is reflected in the trend (rise followed by a fall) of CHD morbidity and mortality as well. In spite of a declining trend in serum TC level, CHD morbidity and mortality are still high in Singapore and comparable to the Western countries. The rest of the Asian countries show a different pattern from Singapore. In general, there is still a rising trend in serum TC level and in CHD mortality in most Asian countries. However, Japan is considered an exception in having a decreasing CHD mortality in spite of an increasing trend in serum TC. This may be attributed to a better control of other CHD risk factors such as hypertension and smoking. The rising trend in serum TC level remains a cause for concern, as this will emerge as a major problem for CHD morbidity and mortality in the future.

MRC/BHF Heart Protection Study of cholesterol-lowering with simvastatin in 5963 people with diabetes: a randomised placebo-controlled trial

BACKGROUND

Individuals with diabetes are at increased risk of cardiovascular morbidity and mortality, although typically their plasma concentrations of LDL cholesterol are similar to those in the general population. Previous evidence about the effects of lowering cholesterol in people with diabetes has been limited, and most diabetic patients do not currently receive cholesterol-lowering therapy despite their increased risk.

METHODS

5963 UK adults (aged 40-80 years) known to have diabetes, and an additional 14573 with occlusive arterial disease (but no diagnosed diabetes), were randomly allocated to receive 40 mg simvastatin daily or matching placebo. Prespecified analyses in these prior disease subcategories, and other relevant subcategories, were of first major coronary event (ie, non-fatal myocardial infarction or coronary death) and of first major vascular event (ie, major coronary event, stroke or revascularisation). Analyses were also conducted of subsequent vascular events during the scheduled treatment period. Comparisons are of all simvastatin-allocated versus all placebo-allocated participants (ie, intention to treat), which yielded an average difference in LDL cholesterol of 1.0 mmol/L (39 mg/dL) during the 5-year treatment period.

FINDINGS

Both among the participants who presented with diabetes and among those who did not, there were highly significant reductions of about a quarter in the first event rate for major coronary events, for strokes, and for revascularisations. For the first occurrence of any of these major vascular events among participants with diabetes, there was a definite 22% (95% CI 13-30) reduction in the event rate (601 [20.2%] simvastatin-allocated vs 748 [25.1%] placebo-allocated, p<0.0001), which was similar to that among the other high-risk individuals studied. There were also highly significant reductions of 33% (95% CI 17-46, p=0.0003) among the 2912 diabetic participants who did not have any diagnosed occlusive arterial disease at entry, and of 27% (95% CI 13-40, p=0.0007) among the 2426 diabetic participants whose pretreatment LDL cholesterol concentration was below 3.0 mmol/L (116 mg/dL). The proportional reduction in risk was also about a quarter among various other subcategories of diabetic patient studied, including: those with different duration, type, or control of diabetes; those aged over 65 years at entry or with hypertension; and those with total cholesterol below 5.0 mmol/L (193 mg/dL). In addition, among participants who had a first major vascular event following randomisation, allocation to simvastatin reduced the rate of subsequent events during the scheduled treatment period.

INTERPRETATION

The present study provides direct evidence that cholesterol-lowering therapy is beneficial for people with diabetes even if they do not already have manifest coronary disease or high cholesterol concentrations. Allocation to 40 mg simvastatin daily reduced the rate of first major vascular events by about a quarter in a wide range of diabetic patients studied. After making allowance for non-compliance, actual use of this statin regimen would probably reduce these rates by about a third. For example, among the type of diabetic patient studied without occlusive arterial disease, 5 years of treatment would be expected to prevent about 45 people per 1000 from having at least one major vascular event (and, among these 45 people, to prevent about 70 first or subsequent events during this treatment period). Statin therapy should now be considered routinely for all diabetic patients at sufficiently high risk of major vascular events, irrespective of their initial cholesterol concentrations.

Reduction in serum total cholesterol and risks of coronary events and cerebral infarction in Japanese men: the Kyushu Lipid Intervention Study

Lowering serum total cholesterol is shown to decrease the risk of coronary heart disease (CHD) in Western countries,but evidence is limited regarding cerebral infarction (CI). The present study used the Kyushu Lipid Intervention Study to examine the risks of CHD events and CI in relation to reduction in serum total cholesterol. Subjects were 4,615 men aged 45-74 years with serum total cholesterol of 220 mg/dl (5.68 mmol/L) or greater who had no history of CHD events or stroke. CHD events and CI numbered 125 and 92, respectively, in a 5-year follow-up. After adjustment for potential confounding factors, the relative risks of CHD events and CI for 15% or greater reduction in total cholesterol, compared with less than 5% reduction, were 0.78 (95% confidence limit [CL]0.46-1.32) and 0.39 (95% CL 0.22-0.69), respectively. As compared with on-treatment cholesterol levels of 240 mg/dl (6.20 mmol/L)or higher, the risk of CHD events was approximately 50% lower across 3 categories below 240 mg/dl (6.20 mmol/L), and that of CI was 70%lower at 2 categories below 220 mg/dl (5.68 mmol/L). Lowering serum total cholesterol below 220 mg/dl (5.68 mmol/L) seems desirable with regard to the prevention of CI.

Reduction of serum LDL-C levels: a relationship to clinical benefits

The association between elevated serum cholesterol levels and cardiovascular risk was established several decades ago by studies such as the Framingham study and the Multiple Risk Factor Intervention Trial (MRFIT). Both primary and secondary prevention trials of cholesterol lowering, using HMG-CoA reductase inhibitors, have demonstrated clear benefits for lipid lowering in preventing both cardiovascular morbidity and mortality over a wide spectrum of coronary heart disease (CHD) risk. Even so, risk of events has been reduced by about 30% in these trials, leaving 70% of events occurring even in the presence of substantial cholesterol lowering. It is unknown whether further reduction of serum cholesterol levels will lower risk factors. The relationship between cholesterol lowering and cardiovascular risk, moreover, is not completely defined; it is unclear, at lower cholesterol levels, whether that relationship follows a threshold, a linear, or a curvilinear model. Early studies of low-density lipoprotein-cholesterol (LDL-C) lowering with HMG-CoA reductase inhibitors suggested that non-cardiovascular mortality might be increased at low serum LDL-C levels, however, these concerns have not been supported by subsequent clinical trials. Recent studies have shed further light on the potential benefits of lowering serum cholesterol levels beyond current guideline targets with HMG-CoA reductase inhibitors. More potent agents in development are likely to make such levels more readily achievable, as well as making guideline targets attainable for many of the large number of patients who currently fail to reach them.

The future direction of cholesterol-lowering therapy

PURPOSE OF REVIEW

Observational studies suggest a continuous positive relationship between vascular risk and cholesterol without any lower threshold level. We review recent and future clinical trials addressing the question of optimal treatment goals for cholesterol reduction and how these relate to present guidelines. With increasing focus on greater cholesterol reduction, new approaches to lipid-lowering therapy are being developed; we discuss some of these agents including the new statin, rosuvastatin and novel cholesterol transport inhibitors such as ezetimibe.

RECENT FINDINGS

The Heart Protection Study demonstrated that LDL cholesterol reduction to levels as low as 1.7 mmol/l was associated with significant clinical benefit in a wide range of high-risk individuals, irrespective of baseline cholesterol levels, with no apparent threshold level for LDL cholesterol with respect to cardiovascular risk. The Heart Protection Study also demonstrated that the benefits of LDL cholesterol reduction extend into peripheral vascular disease and cerebrovascular disease prevention and suggest that the most recent National Cholesterol Education Program Adult Treatment Panel III guidelines, with LDL cholesterol targets of 2.6 mmol/l, may result in undertreatment of a large number of patients. Various large end-point trials, including Treating to New Targets and Study of Effectiveness of Additional Reductions in Cholesterol and Homocysteine will attempt to further address the issue of optimal LDL cholesterol reduction. New therapies are being developed to meet the challenge of more intensive cholesterol lowering. Rosuvastatin is a potent, hydrophilic enantiomeric statin producing reductions in LDL cholesterol of 40-69% over its dose range of 5-80 mg. Ezetimibe is a selective cholesterol absorption inhibitor, with a site of action at the intestinal epithelium. Optimum reductions in LDL cholesterol of up to 25 and 60% reduction in chylomicron cholesterol content are seen with a 10-mg dose.

SUMMARY

Evidence is accumulating supporting the safety and benefits of aggressive cholesterol reduction, with no apparent threshold for LDL cholesterol. New therapies will aid in achieving lower cholesterol levels and the use of combination therapies targeting different aspects of cholesterol metabolism may produce additional benefits. Outcome studies are awaited to further address these issues.

MRC/BHF Heart Protection Study of cholesterol lowering with simvastatin in 20,536 high-risk individuals: a randomised placebo-controlled trial

BACKGROUND

Throughout the usual LDL cholesterol range in Western populations, lower blood concentrations are associated with lower cardiovascular disease risk. In such populations, therefore, reducing LDL cholesterol may reduce the development of vascular disease, largely irrespective of initial cholesterol concentrations.

METHODS

20,536 UK adults (aged 40-80 years) with coronary disease, other occlusive arterial disease, or diabetes were randomly allocated to receive 40 mg simvastatin daily (average compliance: 85%) or matching placebo (average non-study statin use: 17%). Analyses are of the first occurrence of particular events, and compare all simvastatin-allocated versus all placebo-allocated participants. These "intention-to-treat" comparisons assess the effects of about two-thirds (85% minus 17%) taking a statin during the scheduled 5-year treatment period, which yielded an average difference in LDL cholesterol of 1.0 mmol/L (about two-thirds of the effect of actual use of 40 mg simvastatin daily). Primary outcomes were mortality (for overall analyses) and fatal or non-fatal vascular events (for subcategory analyses), with subsidiary assessments of cancer and of other major morbidity.

FINDINGS

All-cause mortality was significantly reduced (1328 [12.9%] deaths among 10,269 allocated simvastatin versus 1507 [14.7%] among 10,267 allocated placebo; p=0.0003), due to a highly significant 18% (SE 5) proportional reduction in the coronary death rate (587 [5.7%] vs 707 [6.9%]; p=0.0005), a marginally significant reduction in other vascular deaths (194 [1.9%] vs 230 [2.2%]; p=0.07), and a non-significant reduction in non-vascular deaths (547 [5.3%] vs 570 [5.6%]; p=0.4). There were highly significant reductions of about one-quarter in the first event rate for non-fatal myocardial infarction or coronary death (898 [8.7%] vs 1212 [11.8%]; p<0.0001), for non-fatal or fatal stroke (444 [4.3%] vs 585 [5.7%]; p<0.0001), and for coronary or non-coronary revascularisation (939 [9.1%] vs 1205 [11.7%]; p<0.0001). For the first occurrence of any of these major vascular events, there was a definite 24% (SE 3; 95% CI 19-28) reduction in the event rate (2033 [19.8%] vs 2585 [25.2%] affected individuals; p<0.0001). During the first year the reduction in major vascular events was not significant, but subsequently it was highly significant during each separate year. The proportional reduction in the event rate was similar (and significant) in each subcategory of participant studied, including: those without diagnosed coronary disease who had cerebrovascular disease, or had peripheral artery disease, or had diabetes; men and, separately, women; those aged either under or over 70 years at entry; and--most notably--even those who presented with LDL cholesterol below 3.0 mmol/L (116 mg/dL), or total cholesterol below 5.0 mmol/L (193 mg/dL). The benefits of simvastatin were additional to those of other cardioprotective treatments. The annual excess risk of myopathy with this regimen was about 0.01%. There were no significant adverse effects on cancer incidence or on hospitalisation for any other non-vascular cause.

INTERPRETATION

Adding simvastatin to existing treatments safely produces substantial additional benefits for a wide range of high-risk patients, irrespective of their initial cholesterol concentrations. Allocation to 40 mg simvastatin daily reduced the rates of myocardial infarction, of stroke, and of revascularisation by about one-quarter. After making allowance for non-compliance, actual use of this regimen would probably reduce these rates by about one-third. Hence, among the many types of high-risk individual studied, 5 years of simvastatin would prevent about 70-100 people per 1000 from suffering at least one of these major vascular events (and longer treatment should produce further benefit). The size of the 5-year benefit depends chiefly on such individuals' overall risk of major vascular events, rather than on their blood lipid concentrations alone.

Intracerebral hemorrhage: update

The present review focuses on evolving concepts in the pathogenesis and management of deep and lobar intracerebral hemorrhage subtypes, with particular focus on the relationship between lobar intracerebral hemorrhage, apolipoprotein E subtypes and cerebral amyloid angiopathy; deep intracerebral hemorrhage and the potential interaction between hypertension and low cholesterol; and new concepts in medical and surgical therapy for acute intracerebral hemorrhage.

The relationship between lipids/lipoproteins and atherosclerosis in African Americans and whites: the Atherosclerosis Risk in Communities Study

PURPOSE

The relationships between lipids/lipoproteins and atherosclerosis were determined in African Americans and whites to assess the consistency of the relationship between these two groups. Differences could suggest varying biological, environmental, or life-style cofactors influencing development of atherosclerosis.

METHODS

In the Atherosclerosis Risk in Communities Study, 2966 African Americans and 9399 whites had determinations of LDL, HDL, HDL2, and HDL3 cholesterol, triglycerides, apolipoprotein A1 and B, and lipoprotein (a). Carotid intimal-medial thickening (IMT) was measured using B-mode ultrasound imaging.

RESULTS

The associations, using linear regression, between carotid IMT and LDL cholesterol, HDL cholesterol, and other lipid measurements were significantly weaker in African Americans than whites. Averaging men and women, a 1.034 mmol/L (40 mg/dl) difference in LDL cholesterol was associated with a 0.028 mm IMT difference in whites but a 0.019 difference in African Americans. Similarly, for HDL cholesterol, a 0.44 mmol/L (17 mg/dl) difference is associated wth 0.026 mm difference in carotid IMT in whites and 0.011 mm difference in African Americans. The associations are much weaker in African Americans than whites at the bifurcation and internal carotid, the carotid sites most prone to atherosclerosis. Analysis was done stratifying for risk factors that differ between African Americans and whites, but within most, the relationships remained substantially weaker in African Americans.

CONCLUSIONS

We have observed a statistically significant difference in the association between many lipids/lipoproteins and carotid IMT between African Americans and whites. Analysis of many potential cofactors have not provided an explanation for the weaker association. Although possible differences in prior levels of these lipids may provide one explanation for the finding, these results need confirmation in other studies.

Low serum cholesterol as a risk factor for hemorrhagic stroke in men: a community-based mass screening in Okinawa, Japan

The relation between the level of total serum cholesterol and stroke is controversial. The relation between serum total cholesterol and subtypes of stroke was examined in the participants of a community-based mass screening program in Okinawa, Japan. A total of 38,053 subjects, whose serum level of cholesterol had been determined during a mass screening carried out in 1983, were examined to see whether they had experienced stroke during a 3-year period from 1988 to 1991. Of them, 315 subjects aged 33-93 years (174 men, 141 women) had had a stroke during that period. The types of stroke were cerebral infarction in 164, cerebral hemorrhage in 111, subarachnoid hemorrhage in 19, and others in 21. In men, the odds ratio of cerebral hemorrhage was 0.71 (95% confidence interval, 0.55-0.95), and the odds ratio of cerebral hemorrhage associated with serum level of cholesterol < or =167 mg/dl, 168-191 mg/dl, 192-217mg/dl, and > or =218mg/dl were 1.00 (reference), 0.70 (0.38-1.30), 0.77 (0.55-1.08), 0.73 (0.56-0.96), respectively. Lower serum cholesterol was an independent predictor of cerebral hemorrhage in men.

Serum cholesterol and coronary artery disease in populations with low cholesterol levels: the Indian paradox

OBJECTIVE

To examine the relation between serum cholesterol and coronary artery disease prevalence below the range of cholesterol values generally observed in developed countries.

DESIGN AND SETTING

Cross-sectional survey of two randomly selected villages from Moradabad district and 20 randomly selected streets in the city of Moradabad.

SUBJECTS AND METHODS

3575 Indians, aged 25-64 years including 1769 rural (894 men, 875 women) and 1806 urban (904 men, 902 women) subjects. The survey methods were questionnaires, physical examination and electrocardiography.

RESULTS

The overall prevalences of coronary artery disease were 9.0% in urban and 3.3% in rural subjects and the prevalences were significantly (P<0.001) higher in men compared to women in both urban (11.0 vs. 6.9%) and rural subjects (3.9 vs. 2.6%). The average serum cholesterol concentrations were 4.91 mmol/l in urban and 4.22 mmol/l in rural subjects without any sex differences. The prevalences of coronary artery disease were significantly higher among subjects with low and high serum cholesterol concentration compared to subjects with very low cholesterol and showed a positive relation with serum cholesterol within the range of serum cholesterol level studied in both rural and urban in both sexes. Among subjects with low serum cholesterol, there was a higher prevalence of coronary risk factors, hypertension, diabetes, obesity and sedentary lifestyle. Serum cholesterol level showed a significant positive relation with low density lipoprotein cholesterol and triglycerides in all the four subgroups. Logistic regression analysis after pooling of data from both rural and urban, with adjustment of age showed that low serum cholesterol level (odds ratio: men 0.96, women 0.91) had a positive strong relation with coronary artery disease and there was no evidence of any threshold. Diabetes mellitus (men 0.73, women 0.74) and sedentary lifestyle (men 0.86, women 0.74) were significant risk factors of coronary disease in both sexes. Hypertension (men 0.82, women 0.64) and smoking (men 0.81, women 0.52) were weakly associated with coronary disease in men but not in women.

CONCLUSION

Serum cholesterol level was directly related to prevalence of coronary artery disease even in those with low cholesterol concentration (<5.18 mmol/l). It is possible that some Indian populations may benefit by increased physical activity and decline in serum cholesterol below the range of desired serum cholesterol in developed countries.

Lipoprotein changes and reduction in the incidence of major coronary heart disease events in the Scandinavian Simvastatin Survival Study (4S)

BACKGROUND

The Scandinavian Simvastatin Survival Study (4S) randomized 4444 patients with coronary heart disease (CHD) and serum cholesterol 5.5 to 8.0 mmol/L (213 to 310 mg/dL) with triglycerides < or =2.5 mmol/L (220 mg/dL) to simvastatin 20 to 40 mg or placebo once daily. Over the median follow-up period of 5.4 years, one or more major coronary events (MCEs) occurred in 622 (28%) of the 2223 patients in the placebo group and 431 (19%) of the 2221 patients in the simvastatin group (34% risk reduction, P<.00001). Simvastatin produced substantial changes in several lipoprotein components, which we have attempted to relate to the beneficial effects observed.

METHODS AND RESULTS

The Cox proportional hazards model was used to assess the relationship between lipid values (baseline, year 1, and percent change from baseline at year 1) and MCEs. The reduction in MCEs within the simvastatin group was highly correlated with on-treatment levels and changes from baseline in total and LDL cholesterol, apolipoprotein B, and less so with HDL cholesterol, but there was no clear relationship with triglycerides. We estimate that each additional 1% reduction in LDL cholesterol reduces MCE risk by 1.7% (95% CI, 1.0% to 2.4%; P<.00001).

CONCLUSIONS

These analyses suggest that the beneficial effect of simvastatin in individual patients in 4S was determined mainly by the magnitude of the change in LDL cholesterol, and they are consistent with current guidelines that emphasize aggressive reduction of this lipid in CHD patients.

Longitudinal trends in total serum cholesterol levels in a Japanese cohort, 1958-1986

The 28-year follow-up of a Japanese cohort, having collected vast amounts of data collected on total serum cholesterol (TC), provided an exceptional opportunity to examine TC temporal trends. The longitudinal statistical method of growth-curve analysis was used to elucidate the age-related changes in TC levels and to characterize these trends in relation to sex, birth cohort, time period, place of residence, and body mass index (BMI). Japanese TC levels at initial examination were remarkably lower than those in western countries. During the study period from 1958 to 1986, TC levels increased dramatically with age in both sexes. The slope of the cholesterol growth curve was steeper for women than for men, with the difference growing larger after age 40 years. Drastic changes in Japanese behavior and lifestyle, especially westernization of the diet, are thought to have affected the TC values as time-period effects. As a result of this temporal change, which affected different cohorts at different ages, TC values were higher in members of the younger cohort. The increase of the TC values as time-period effects were larger in earlier period than in later period. These time-period effects appeared to be almost similar in men and women. The TC growth curves also varied by city of residence. Subjects in urban areas had higher TC values than subjects in rural areas. Changes associated with BMI from 1958 to 1986 were only partially responsible for the increased steepness of the TC growth curve.

The efficacy and six-week tolerability of simvastatin 80 and 160 mg/day

The hydroxymethylglutaryl coenzyme A reductase inhibitor simvastatin is the most effective of the currently approved hypolipidemic drugs and has been shown to reduce mortality and coronary morbidity in patients with coronary artery disease. For these patients the United States National Cholesterol Education Program advocates reducing low-density lipoprotein (LDL) cholesterol to <100 mg/dl. However, in some patients this cannot be achieved using monotherapy with simvastatin 40 mg/day, the current maximal recommended dose. To evaluate the effectiveness of extending the dosage range, 156 subjects with LDL cholesterol >160 mg/dl and triglycerides (TG) <350 mg/dl were randomized to simvastatin at doses of 40, 80, and 160 mg/day in a 26 week, double-blind, 3-period, complete block crossover study. Each active treatment period was 6 weeks in duration with intervening 2 week washout periods. Median reductions from baseline in LDL cholesterol were 41%, 47%, and 53% in the 40-, 80-, and 160-mg groups, respectively. The corresponding reductions in plasma TG were 21%, 23%, and 33%. High-density lipoprotein (HDL) cholesterol increased by 6% to 8% in each group. One patient (0.7%) taking 160 mg developed myopathy; 1 patient (0.7%) taking 80 mg, and 3 (2.1%) taking 160 mg had transaminase elevations > 3 times the upper limit of normal. No new or unexpected adverse effects were observed. We conclude that simvastatin at doses of 80 and 160 mg/day provides additional efficacy with a low short-term incidence of adverse effects; our results support the continued investigation of simvastatin at these doses.

A coronary primary intervention study of Japanese men: study design, implementation and baseline data. The Kyushu Lipid Intervention Study Group

This report describes the design and baseline results of the Kyushu Lipid Intervention Study (KLIS). The study aims to test the hypothesis that the long term reduction of serum total cholesterol by pravastatin will lead to a decrease in coronary heart disease (CHD) events. The trial was designed to include a random 6,000 male patients aged 45-74 years with serum total cholesterol of 220 mg/dl (5.69 mmol/l) or greater and without a history of myocardial infarction, coronary surgery or angioplasty, to undertake either pravastatin or conventional treatment (including hypolipidemic drugs other than HMG CoA reductase inhibitors, probucol and bezafibrate), and to follow up each patient for 5 years. Primary endpoints are fatal and nonfatal myocardial infarction, coronary bypass surgery and angioplasty, cardiac death, and sudden and unexpected death. During the period from May 1990 to September 1993, a total of 5,640 male patients aged 45-74 were recruited by 902 participating physicians throughout Kyushu. Randomization was, however, neglected by study physicians; the numbers of patients enrolled were 3,061 in the pravastatin group and 2,579 in the conventional treatment group. Patients allocated to the pravastatin treatment were generally unfavorable regarding coronary risk factors. Baseline mean levels of serum total cholesterol were 259 mg/dl (6.70 mmol/l) in the pravastatin group and 246 mg/dl (6.36 mmol/l) in the conventional treatment group (p <0.001). Although the trial was regarded as a prospective observational study, the KLIS provides valuable quantitative data regarding cholesterol lowering and reduction in CHD events as well as safety data of the long-term use of a statin in Japanese men with hypercholesterolemia.

Intracerebral hemorrhage versus infarction: stroke severity, risk factors, and prognosis

The purpose of this study was to compare stroke severity, risk factors, and prognosis in patients with intracerebral hemorrhage versus infarction. We prospectively studied 1,000 unselected patients with acute stroke of a verified type in the Copenhagen Stoke Study. Neurological deficits and functional disabilities were evaluated weekly from the time of acute admission throughout the rehabilitation period. Eighty-eight (9%) had intracerebral hemorrhage. The relative frequency of intracerebral hemorrhage rose exponentially with increasing stroke severity. In multivariate analyses, stroke type had no influence on mortality, neurological outcome, functional outcome, or the time course of recovery. Initial stroke severity was the all-important prognostic factor. The relative importance of hypertension and blood pressure on admission was not greater for intracerebral hemorrhage than for infarction. No preponderance was found between type of stroke and sex, age, and smoking. Diabetes, ischemic heart disease, and elevated serum total cholesterol level all favored cerebral infarction as opposed to intracerebral hemorrhage. We conclude that the type of stroke per se has no influence on stroke prognosis in general; the extent of the injury is decisive. The poorer prognosis in patients with intracerebral hemorrhage is due to the increase in frequency of intracerebral hemorrhage with increasing stroke severity. The likelihood of cerebral infarction occurring as opposed to intracerebral hemorrhage seems increased fivefold in stroke patients with diabetes. Hypertension and blood pressure on admission were not predictors of stroke type.

Serum cholesterol and acute myocardial infarction: a case-control study from the GISSI-2 trial. Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto-Epidemiologia dei Fattori di Rischio dell'Infarto Miocardico Investigators

OBJECTIVE

To examine the role of serum cholesterol in acute myocardial infarction in a population of patients with no history of coronary heart disease and to establish the nature of this association, the degree of risk, and the possible interaction between serum cholesterol and other major risk factors for acute myocardial infarction.

DESIGN

Case-control study.

SETTING

90 hospitals in northern, central, and southern Italy.

PATIENTS

916 consecutive cases of newly diagnosed acute myocardial infarction and 1106 hospital controls admitted to hospital with acute conditions not related to known or suspected risk factors for coronary heart disease.

DATA COLLECTION

Data were collected with a structured questionnaire and blood samples were taken by venepuncture as soon as possible after admission to hospital from cases and controls. Blood cholesterol concentrations were available for 614 cases and 792 controls.

RESULTS

After adjustment by logistic regression for sex, age, education, geographical area, smoking status, body mass index, history of diabetes and hypertension, and family history of coronary heart disease the estimated relative risks of acute myocardial infarction for quintiles of serum cholesterol (from lowest to highest) were 2.3 (95% confidence interval (CI) 1.6 to 3.4), 3.1 (95% CI 2.1 to 4.6), 4.1 (95% CI 2.8 to 6.0), and 5.2 (95% CI 3.5 to 7.7). The estimated relative risk across selected covariates increased from the lowest to the highest quintile of serum cholesterol particularly for men, patients under 55 years of age, and smokers. When the possible interaction of known risk factors with serum cholesterol was examined, smoking habits, diabetes, and hypertension had approximately multiplicative effects on relative risk.

CONCLUSIONS

This study indicates that serum cholesterol was an independent risk factor for acute myocardial infarction. This association was linear, with no threshold level. Moreover, there was a multiplicative effect between cholesterol and other major risk factors on the relative risk of acute myocardial infarction.

Body iron stores and the risk of coronary heart disease

BACKGROUND

Recent studies have suggested an association between higher body iron stores and the risk of coronary heart disease. To assess these findings, we examined the association between transferrin saturation and the risk of coronary heart disease, myocardial infarction, overall mortality, and mortality from cardiovascular causes in a large population.

METHODS

We studied a total of 4518 men and women from the first National Health and Nutrition Examination Survey Epidemiologic Follow-up Study, using a multivariate Cox proportional-hazards model. Base-line data were collected from 1971 to 1974, with follow-up through 1987. Transferrin saturation (serum iron concentration divided by total iron-binding capacity) was used as a measure of the amount of circulating iron available to tissues.

RESULTS

The risk of coronary heart disease was not related to transferrin-saturation levels in white men or women. Estimates of the relative risk of coronary heart disease for the fifth quintile of transferrin saturation as compared with the first quintile were 0.72 (95 percent confidence interval, 0.51 to 1.00) for men and 0.85 (95 percent confidence interval, 0.60 to 1.21) for women. The results were similar for myocardial infarction. A significant inverse association with transferrin saturation was found for overall mortality and for mortality from cardiovascular causes in white men and women. Transferrin saturation was not associated with any of the clinical outcomes in blacks, possibly owing to the small sample.

CONCLUSIONS

Higher transferrin-saturation levels were not associated with an increased risk of coronary heart disease or myocardial infarction. On the contrary, the results indicate that there may be an inverse association of iron stores with overall mortality and with mortality from cardiovascular causes.

Elevated serum cholesterol is a risk factor for both coronary heart disease and thromboembolic stroke in Hawaiian Japanese men. Implications of shared risk

BACKGROUND AND PURPOSE

The relation between total serum cholesterol level and thromboembolic or nonhemorrhagic stroke is controversial. The Honolulu Heart Program cohort of Japanese-American men provides data which show that elevated serum cholesterol is an independent predictor of thromboembolic stroke as well as coronary heart disease (CHD). The data are presented to suggest that the association of elevated cholesterol with stroke is sometimes underestimated or underreported partly because of competing or shared risk with CHD, the other major atherosclerotic end point.

METHODS

The data are based on 6352 men (aged 51 to 74 years) at baseline examination (1971 to 1974) who were free of clinical CHD and stroke and were followed an average of 15 years for new cases of both end points. Relative risks of serum cholesterol for CHD and thromboembolic stroke were calculated, controlling for other major cardiovascular covariates.

RESULTS

There was a continuous and progressive increase in both CHD and thromboembolic stroke rates with increasing levels of serum cholesterol. The relative risk between the highest and lowest quartiles of serum cholesterol was 1.7 (95% confidence interval, 1.4 to 2.0) for CHD and 1.4 (95% confidence interval, 1.1 to 1.9) for thromboembolic stroke. There was a decline in the difference in relative risks between CHD and thromboembolic stroke in older men (aged 60 years and older) compared with younger men (aged younger than 60 years).

CONCLUSIONS

These data provide additional evidence that elevated serum cholesterol should be considered a primary risk factor for thromboembolic stroke, presumably through its effect on both coronary and cerebrovascular atherosclerosis. It is suggested that this association is sometimes underestimated or underreported partly because of shared or competing risk with CHD, the clinical manifestation of atherosclerosis that generally occurs earlier in life and with greater frequency than thromboembolic stroke.

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.

Relationship between hemoglobin and cardiovascular risk factors in young adults

To understand mechanisms of association between hemoglobin and cardiovascular disease (CVD), the relationships between hemoglobin and CVD risk factors were examined in 5115 black and white men and women who participated in the Coronary Artery Risk Development in Young Adults (CARDIA) Study. Hemoglobin was higher in men than women, whites than blacks, and smokers than non-smokers (p < 0.001). After adjusting for age, body mass index, current smoking status, and clinical center, hemoglobin correlated with diastolic blood pressure (0.11 < or = r < or = 0.22, p < 0.001) and plasma total cholesterol (0.08 < or = r < or = 0.11, p < 0.01) in all four race-sex groups and with systolic blood pressure in all but black women (0.07 < or = r < or = 0.13, p < 0.05). Among other factors possibly related to CVD risk, only serum albumin and white blood cell count showed significant correlations with hemoglobin in all groups (0.19 < or = r < or = 0.27, 0.07 < or = r < or = 0.18, respectively). These findings suggest that an association of hemoglobin with CVD risk factors may explain the association of hemoglobin with CVD.

Lipoprotein and apolipoprotein profile in men with ischemic stroke. Role of lipoprotein(a), triglyceride-rich lipoproteins, and apolipoprotein E polymorphism

BACKGROUND AND PURPOSE

The role of lipoprotein abnormalities in the development of ischemic cerebrovascular disease has not been sufficiently clarified. The aim of this study was to identify the lipoprotein profile in ischemic cerebrovascular disease and the possible role of apolipoprotein E polymorphism.

METHODS

The relation between the concentrations of lipoprotein(a), intermediate density lipoproteins, apolipoprotein A-I, apolipoprotein B, apolipoprotein E, and other lipoproteins was studied in 100 men with ischemic cerebrovascular disease (48 atherothrombotic, 28 lacunar, and 24 of unknown type) and in 100 healthy age-matched men as a control group.

RESULTS

Patients with ischemic cerebrovascular disease had significantly higher levels of lipoprotein(a), lipids carried by intermediate density lipoproteins, and low density lipoprotein cholesterol and lower levels of high density lipoproteins than control subjects. Patients with atherothrombotic infarction had higher total serum cholesterol and low density lipoprotein cholesterol concentrations than patients with lacunar infarction. To assess lipoprotein abnormalities in normolipidemic subjects, a subgroup of 38 patients with ischemic cerebrovascular disease and 53 control subjects, both with serum cholesterol levels < 5.2 mmol/l (200 mg/dl) and triglycerides < 2.3 mmol/l (200 mg/dl), was analyzed. Serum lipoprotein(a), lipids carried by very low density lipoproteins and intermediate density lipoproteins, and low density lipoprotein triglycerides were significantly higher in normolipidemic patients compared with normolipidemic control subjects, whereas high density lipoprotein cholesterol levels were lower. Apolipoprotein E polymorphism in our ischemic cerebrovascular patients differed from that of the control group, with the epsilon 4 allele being more prevalent.

CONCLUSIONS

Increased serum lipoprotein(a) levels and intermediate density lipoprotein abnormalities together with decreased high density lipoprotein levels are major risk factors for ischemic cerebrovascular disease, even in normocholesterolemic and normotriglyceridemic subjects. Finally, the epsilon 4 allele could probably be a predisposing genetic marker for ischemic cerebrovascular disease.

Report of the Conference on Low Blood Cholesterol: Mortality Associations

BACKGROUND

A National Heart, Lung, and Blood Institute (NHLBI) Conference was held October 9-10, 1990, to review and discuss existing data on U-shaped relations found between mortality rates and blood total cholesterol levels (TC) in some but not other studies. Presentations were given from 19 cohort studies from the United States, Europe, Israel, and Japan. A representative of each study presented its findings and also submitted tables of proportional hazards regression coefficients for entry TC levels in regard to death, and these were incorporated into a formal statistical overview adjusted for age, diastolic blood pressure, cigarette smoking, body mass index, and alcohol intake, as available.

METHODS AND RESULTS

The U-shape for total mortality in men and the flat relation in women resulted largely from a positive relation of TC with coronary heart disease death and an inverse relation with deaths caused by some cancers (e.g., lung but not colon), respiratory disease, digestive disease, trauma, and residual deaths. Risk for combined noncardiovascular, noncancer causes of death decreased steadily across the range of TC. The conference considered possible explanations for the statistical associations found between low TC levels or active TC lowering and certain causes of death. One is that TC is lowered by some disease conditions themselves, such as wasting in chronic pulmonary disease or reduced production and secretion of cholesterol-bearing lipoproteins with liver disease. In this sort of situation, the TC:mortality association found in observational studies may be due to preexisting disease. This was addressed by excluding early deaths from the analysis, which did not change the results. The conference considered as well the biological function of cholesterol, which, if seriously deranged, might hypothetically cause a wide variety of diseases and dysfunction. The conference also considered the biological functions that might provide plausible mechanisms for the associations found.

CONCLUSIONS

Definitive interpretation of the associations observed was not possible, although most participants considered it likely that many of the statistical associations of low or lowered TC level are explainable by confounding in one form or another. The conference focused on the apparent existence and nature of these associations and on the need to understand their source rather than on any pertinence of the findings for public health policy. Further research is recommended to explain the observed associations of low TC levels (and TC lowering) with certain noncardiovascular diseases. This includes studies of the time course of TC change in disease, the relation of TC to morbidity, further studies of possible epidemiological confounding, monitoring of population trends in TC and mortality, further studies of the relations in women, auditing of noncardiovascular events in trials, studies of cell membrane, genetic and molecular links to cholesterol metabolism, TC level and disease, studies of disease manifestations in specific lipid disorders, and further study of the proposed causal mechanisms linking low TC and hemorrhagic stroke.

Effects of traditional coronary risk factors on rates of incident coronary events in a low-risk population. The Adventist Health Study

BACKGROUND

California Seventh-Day Adventists have lower mortality rates from coronary heart disease (CHD) than other Californians. Associations between traditional risk factor and CHD events have not been reported previously for Adventists.

METHODS AND RESULTS

A cohort study allowed 6 years of follow-up of 27,658 male and female California Seventh-Day Adventists. Data collected included age, sex, physician-diagnosed hypertension and diabetes mellitus, body height, weight, previous and current cigarette smoking habits, and current exercise habits. Incident cases of definite myocardial infarction (MI) and definite fatal CHD were diagnosed according to recognized criteria. Both stratified and proportional hazards analyses demonstrated that in this low-risk population, the above traditional coronary risk factors exhibit their usual associations with risk of CHD events. It was noted that exercise had a strong negative association with fatal CHD events (relative risks [RR], 1.0, 0.66, and 0.50 with increasing exercise) but no association with risk of MI (either nonfatal or all cases). Conversely, obesity was much more clearly associated with MI (RR, 1.0, 1.18, and 1.83 with increasing tertiles of obesity) than with fatal events. The importance of the risk factors was similar in both sexes, except that the effect of cigarette smoking seemed more pronounced in women.

CONCLUSIONS

The epidemiology of coronary heart disease in this low-risk California population appears to be at least qualitatively similar to that seen in other groups. There was evidence that the effects of exercise and obesity may differ depending on whether fatal CHD and MI (either all MI or nonfatal alone) is the end point.

Longitudinal study of the association between ABO phenotype and total serum cholesterol level in a Japanese cohort

The relationship between ABO blood phenotype and total serum cholesterol (TC) level was examined in a Japanese population to determine whether an elevated TC level is associated with phenotype A, as has been demonstrated in many West European populations. Such studies in nonwhite populations are scarce, and findings generally failed to demonstrate the relationship. Inconsistent results from cross-sectional studies of various racial groups with widely varying ages raised an age effect as a possible explanatory factor. It was also suggested that the ABO-TC association may not be apparent in populations with low fat intake or low mean cholesterol level. These hypotheses are addressed by examining long-term TC data collected serially from the unexposed controls of the atomic bomb survivors in Hiroshima and Nagasaki who were participants of the Adult Health Study program at the Atomic Bomb Casualty Commission-Radiation Effects Research Foundation between 1958 and 1986. The statistical method of growth curve analysis, through the mixed effect model of Laird and Ware [1982], was used to model age-dependent changes in cholesterol levels within individuals. The effects of the ABO polymorphism in modifying the resultant growth curve are examined. We demonstrate that TC levels are elevated on average by about 4 mg/dl in phenotype A compared to non-A in the Japanese (P < 0.00001), and that this relationship is maintained from early to late adulthood, independent of sex, body mass index, cohort status, or city of residence. Thus, phenotype A individuals may be more predisposed to cardiovascular disease through one of its major risk factors. This is the first study of the ABO-cholesterol association in the Japanese, and the first based on a cohort with longitudinally collected TC data.

Cardiovascular risk factors among Asian Americans living in northern California

BACKGROUND

Recent substantial immigration has created large population subsets of Asian Americans in the United States. Available data about cardiovascular risk factors in these persons are sparse.

METHODS

This study examined data among 13,031 persons self-classified as 5951 Chinese, 4211 Filipinos, 1703 Japanese, and 1166 other Asians. Covariates in regression analyses were age, smoking, alcohol, education, and marital status.

RESULTS

Chinese men and women had the lowest adjusted mean body mass index. Filipino men and women had the highest prevalence of hypertension. There were no major differences in blood glucose levels. Total cholesterol levels were highest in Japanese men and women. Comparisons of US-born persons and those born in respective countries of origin showed no major cholesterol or glucose differences; more hypertension only in Chinese and other Asian men; higher body mass index in men, but not in women of most ethnicities; and a lower smoking prevalence in men, but a substantially higher one in women.

CONCLUSIONS

These data show important ethnic differences in risk factors among Asian Americans and indicate groups that should be targeted for public health efforts concerned with obesity (Asian-American men), hypertension (Filipino-American men and women), hypercholesteremia (all Asian Americans), and smoking cessation (Asian-American women).

Fibrinogen and lipid concentrations as risk factors for transient ischaemic attacks and minor ischaemic strokes

OBJECTIVES

To determine whether fibrinogen and lipid concentrations are risk factors for ischaemic stroke.

DESIGN

Case-control study with a population based comparison within the overall study.

SETTING

Oxfordshire community stroke project and a neurology clinic.

SUBJECTS

105 patients who had a transient ischaemic attack or minor ischaemic stroke and 352 randomly chosen controls matched for age and sex from the same general practitioners as the incident cases. 52 controls were ineligible or refused interview. 104 cases and 241 controls gave blood samples for analysis.

MAIN OUTCOME MEASURES

Response to structured questionnaire, height, weight, blood pressure, and serum concentrations of fibrinogen and lipids.

RESULTS

Adjusted for other variables, odds ratios of ischaemic stroke were 1.78 (95% confidence interval 0.91 to 3.48; p = 0.09) [corrected] for fibrinogen concentrations greater than 3.6 g/l; 1.73 (0.90 to 3.29; p = 0.09) [corrected] for total cholesterol concentrations greater than 6.0 mmol/l; 1.34 (0.69 to 2.61; p greater than 0.4) for low density lipoprotein cholesterol concentrations greater than 3.5 mmol/l; and 0.32 (0.15 to 0.69; p = 0.002) for high density lipoprotein cholesterol concentration greater than 1.2 mmol/l. Similar results emerged comparing only community derived cases with transient ischaemic attacks and controls. The effects of fibrinogen, total cholesterol, and high density lipoprotein cholesterol were significant in a test of trend after adjusting for all other variables in the study (chi 2 = 4.14, p less than 0.05; chi 2 = 4.31, p less than 0.05, and chi 2 = 12.15, p greater than 0.001, respectively). History of ischaemic heart disease and hypertension were the only other variables that showed significance, though both lost significance after adjustment (2.06, p = 0.08 and 1.53, p = 0.2, respectively).

CONCLUSIONS

Fibrinogen and lipids are important risk factors for ischaemic stroke. The pattern of changes mirrors that found in ischaemic heart disease.

Serum cholesterol concentration and coronary heart disease in population with low cholesterol concentrations

OBJECTIVE

To examine the relation between serum cholesterol concentration and mortality (from coronary heart disease and from other causes) below the range of cholesterol values generally seen in Western populations.

DESIGN

Prospective observational study based on 8-13 years of follow up of subjects in a population with low cholesterol concentrations.

SETTING

Urban Shanghai, China.

SUBJECTS

9021 Chinese men and women aged 35-64 at baseline.

MAIN OUTCOME MEASURE

Death from coronary heart disease and other causes.

RESULTS

The average serum cholesterol concentration was 4.2 mmol/l at baseline examination, and only 43 (7%) of the deaths that occurred during 8-13 years of follow up were attributed to coronary heart disease. There was a strongly positive, and apparently independent, relation between serum cholesterol concentration and death from coronary heart disease (z = 3.47, p less than 0.001), and within the range of usual serum cholesterol concentration studied (3.8-4.7 mmol/l) there was no evidence of any threshold. After appropriate adjustment for the regression dilution bias, a 4 (SD 1)% difference in usual cholesterol concentration was associated with a 21 (SD 6)% (95% confidence interval 9% to 35%) difference in mortality from coronary heart disease. There was no significant relation between serum cholesterol concentration and death from stroke or all types of cancer. The 79 deaths due to liver cancer or other chronic liver disease were inversely related to cholesterol concentration at baseline.

CONCLUSION

Blood cholesterol concentration was directly related to mortality from coronary heart disease even in those with what was, by Western standards, a "low" cholesterol concentration. There was no good evidence of an adverse effect of cholesterol on other causes of death.

Hypertension, lipoprotein(a), and apolipoprotein A-I as risk factors for stroke in the Chinese

We analyzed the serum concentrations of lipids and lipoproteins and the prevalence of other risk factors in a case-control study of 304 consecutive Chinese patients with acute stroke (classified as cerebral infarction, lacunar infarction, or intracerebral hemorrhage) and 304 age- and sex-matched controls. For all strokes we identified the following risk factors: a history of ischemic heart disease, diabetes mellitus, or hypertension; the presence of atrial fibrillation or left ventricular hypertrophy; a glycosylated hemoglobin A1 concentration of greater than 9.1%; a fasting plasma glucose concentration 3 months after stroke of greater than 6.0 mmol/l; a serum triglyceride concentration 3 months after stroke of greater than 2.1 mmol/l; and a serum lipoprotein(a) concentration of greater than 29.2 mg/dl. We found the following protective factors: a serum high density lipoprotein-cholesterol concentration of greater than 1.59 mmol/l and a serum apolipoprotein A-I concentration of greater than or equal to 106 mg/dl. The patterns of risk factors differed among the three stroke subtypes. When significant risk factors were entered into a multiple logistic regression model, we found a history of hypertension, a high serum lipoprotein(a) concentration, and a low apolipoprotein A-I concentration to be independent risk factors for all strokes. The attributable risk for hypertension was estimated to be 24% in patients aged greater than or equal to 60 years. In this population, in which cerebrovascular diseases are the third commonest cause of mortality, identification of risk factors will allow further studies in risk factor modification for the prevention of stroke.

Serum cholesterol levels and six-year mortality from stroke in 350,977 men screened for the multiple risk factor intervention trial

We examined the relation between the serum total cholesterol level and the risk of death from stroke during six years of follow-up in 350,977 men, 35 to 57 years of age, who had no history of heart attack and were not currently being treated for diabetes mellitus. The diagnosis of stroke and the type of stroke were obtained from death certificates. Using proportional-hazards regression to control for age, cigarette smoking, diastolic blood pressure, and race or ethnic group, we found that the six-year risk of death from intracranial hemorrhage (International Classification of Diseases, ninth edition [ICD-9], categories 431 and 432) was three times higher in men with serum cholesterol levels under 4.14 mmol per liter (160 mg per deciliter) than in those with higher cholesterol levels (P = 0.05 by omnibus test across five cholesterol levels). On the other hand, a positive association was observed between the serum cholesterol level and death from nonhemorrhagic stroke (P = 0.007). The inverse association of the serum cholesterol level with the risk of death from intracranial hemorrhage was confined to men with diastolic blood pressure greater than or equal to 90 mm Hg, in whom death from intracranial hemorrhage is relatively common. We conclude that there is an inverse relation between the serum cholesterol level and the risk of death from hemorrhagic stroke in middle-aged American men, but that its public health impact is overwhelmed by the positive association of higher serum cholesterol levels with death from nonhemorrhagic stroke and total cardiovascular disease (ICD-9 categories 390 through 459).

Stroke mortality in Miyagi, Japan

Hypertension is a major cause in stroke mortality in Japan but is not the sole factor. This research, based on geographical comparisons between two selected towns of contrasted stroke experience, implicates a poor indoor thermal environment as having an important role, especially by sudden changes in temperature between rooms elevating blood pressure. High dietary salt is also an important contributory cause of stroke and is already the target of a public education campaign to encourage a reduced intake.

Haematologic parameters as risk factors for cardiac infarction, in an occupational health care setting

It is still controversial, whether moderately high haematocrit (Ht) and haemoglobin (Hb) values are risk factors for coronary heart disease. Using the computerized data-system of the Periodical Medical Examination (PME) of Phillips' International Electrical Company, a case-control study was carried out. Cases were male workers (n = 104, from 50 to 60 years of age) who had suffered a first, non-fatal myocardial infarction, and who had had a PME prior (on the average 16 months) to the occurrence of infarction. For each case two age-matched healthy controls were selected from the PME-attendancy list (= 208). For each subject information was abstracted from the PME-records about haematologic parameters and covariates (smoking, cholesterol, blood pressure, pulse-rate, weight, height, FEV5, consumption of antihypertensive agents). After dichotomizing the haematocrit and haemoglobin values at their whole sample means (0.46 l/l and 9.7 mmol/l respectively) in "low" (lower than or equal to the mean) and "high" (greater than the mean), crude odds-ratio's of 2.7 (95% CI: 1.6-4.6) and 2.1 (95% CI: 1.2-3.6) were found for Ht and Hb respectively, when comparing "high" with "low" levels. The associations between Ht and Hb, and the occurrence of myocardial infarction were still present after controlling for covariates using multiple logistic regression models, entering the continuous variables with their exact values. After adjustment, mean corpuscular volume (MCV) also appeared to be correlated with infarction. Our results confirm the hypothesis that moderately high haematocrit and--to a lesser extent--haemoglobin and MCV-values are risk factors for the occurrence of myocardial infarction.

Mortality, haemoglobin level and haematocrit in women

The mortality of 1438 women aged 45-74 from South Wales has been studied from 1967-1978 using techniques of survival analysis to determine whether the haemoglobin level (Hb) or the haematocrit (PCV) are risk factors for death due to ischaemic heart disease (IHD), cerebrovascular accident (CVA) or cancer. In the 858 women who were not menstruating and who did not complain of angina at the time of the survey a PCV over 45% was a significant risk factor for IHD mortality. An Hb level over 14 g/dl was also a risk factor but this failed to reach conventional significance, when smoking was allowed for. In the 1098 women who were not menstruating an Hb less than 12 g/dl or a PCV less than 40% are increased risk factors for cancer and this risk persisted throughout the follow-up period. Neither Hb nor PCV were significant risk factors for CVA mortality.