Individual Coronary Heart Disease Risk Research Articles

Relationships between Risk Factors for Coronary Artery Disease and Aspirin Resistance.

Aspirin prevents or delays atherogenesis and subsequent arterial occlusions. Patients who are relatively resistant to aspirin have a higher rate of vascular occlusive events. We evaluated the hypothesis that in patients with a previous myocardial infarction (MI) relative resistance to aspirin was related to risk factors for coronary heart disease (CHD). We studied 192 patients with a history of at least 1 MI including 136 males and 64 females. Mean age was 62. Compliance was assured by studying patients 2 hours after they were observed to ingest 325mg aspirin and confirmed with a qualitative assay (arachidonic acid 1.0mM stimulated light aggregometry) that detected aspirin inhibition of platelet aggregation in all of the study patients. To assess amount of aspirin inhibition of platelet aggregation (aspirin resistance) platelet prostaglandin agonist (PPA) 30mM stimulated light aggregation was performed (Schwartz J. Lab Clin Med 2002; 139:227). A CHD risk assessment score that includes diabetes, HDL, total cholesterol, high blood pressure (HBP) smoking and age was used as a measure of 10 year risk for CHD. Statistical comparisons were evaluated using a univariate general linear model. A significant relationship was observed between platelet resistance to aspirin inhibition and increased CHD risk (p=0.03). Evaluation of individual CHD risk factors showed that diabetic patients were more resistant to aspirin as demonstrated by an increased slope of aggregation (p=0.02) a decreased time to 50% aggregation (p=0.04) and a linear relationship between an increase in fasting blood sugar and an increased aggregation slope (p=0.05). A higher (BMI) (p=0.05) or a lower HDL (p=0.02) were also related to aspirin resistance. Although decreased aspirin inhibition of platelets was observed in patients who smoked or had HBP, these differences were not significant. We conclude that in patients with CHD a relative resistance to aspirin inhibition of platelet aggregation correlates with a commonly used risk assessment equation and with the presence of diabetes, increasing BMI or decreasing HDL. This suggests the hypothesis that CHD patients who have a higher risk for CHD, or those who have diabetes or obesity or a decreased HDL, may benefit from additional platelet inhibiting medications.

Characterizing Coronary Heart Disease Risk in Chronic Schizophrenia: High Prevalence of the Metabolic Syndrome

To determine the prevalence and characteristics of coronary heart disease (CHD) risk factors in patients with chronic schizophrenia or schizoaffective disorder. We compared individual CHD risk factors and Framingham risk predictions in a group of 240 patients with a large national sample (Canadian Heart Health Survey) matched for age and sex. In addition, we compared rates of the metabolic syndrome (syndrome X) with recently published rates in the US adult population. Compared with the reference population, Framingham 10-year risk of myocardial infarction was greater in the male patients (t3091 = 4.35, P < 0.001) but not in the female patients. Prevalence rates of the metabolic syndrome in the patients (42.6% of men and 48.5% of women) were approximately 2 times published rates in the US adult population. Further, the syndrome appears to occur at a younger age than in the general population. These long-term patients have increased CHD risks best captured by the metabolic syndrome conceptualization coupled with a high rate of cigarette smoking. This characterization is consistent with increased cardiovascular morbidity and decreased life expectancy in both men and women. We underscore the importance of both screening for and treating potentially reversible CHD risk factors in schizophrenia patients.

Coronary risk in South Asians: role of ethnicity and blood sugar

Studies of South Asian immigrants in different countries have reported an increased predisposition to cardiovascular disease in comparison with the native populations. This study is a systematic review of longitudinal studies investigating differences in established risk factors for coronary heart disease (CHD) between Caucasians and South Asians. The aim was to develop a practical tool to estimate CHD risk in individuals. Secondarily data from the Health Survey for England 1999 (HSE 1999) were used to explore a possible role of differences in blood glucose in risk variation. We used a systematic search to find relevant published papers. Data from the HSE 1999 were employed to study ethnic differences in blood glucose and glycosylated haemoglobin. Only two out of five longitudinal studies reported independent estimates of relative risks of CHD in South Asians compared to Caucasians. Risk in diabetic South Asians was predicted adequately by classical risk factors whilst risk in a non-diabetic study population was 79% greater than predicted. Non-diabetic South Asians have higher fasting blood glucose (FBG) and HbA1c than Caucasians after adjustment for CHD risk factors. The difference in risk of CHD between non-diabetic South Asian and Caucasians is not explained by differences in the impact of the traditional risk factors. Part may be due to higher blood sugar concentrations in non-diabetic South Asians.

Coronary heart disease and lipid-modifying treatment in african american patients

African Americans have the highest overall coronary heart disease (CHD) mortality rate of any ethnic group in the United States. They also exhibit a greater prevalence of a number of individual CHD risk factors, especially hypertension and type 2 diabetes mellitus (a CHD risk equivalent) and greater clustering of risk factors. The African-American population is under-represented in lipid-lowering clinical end point trials and remains inadequately treated with lipid-lowering therapy in the clinical setting; this latter fact is of particular concern because, in the new National Cholesterol Education Program guidelines, many more black patients with hypercholesterolemia should be receiving more intensive lipid-lowering treatment. A number of steps must be taken to improve prospects of CHD risk reduction through lipid-lowering therapy in African Americans. These include improving the understanding of the relationship of risk factors to disease and improving the understanding of both lipid responses to and clinical benefits of lipid-lowering therapy. In addition, because African Americans have a higher prevalence of several modifiable CHD risk factors, this population should be rigorously targeted for risk-reduction strategies, including screening and treatment for hypertension, type 2 diabetes mellitus, and dyslipidemia. Educational outreach programs can provide a key role in raising community awareness of CHD risk factors and potential treatment options.

PHYSICAL FITNESS AND THE HYPERTRIGLYCERIDEMIC WAIST PHENOTYPE

A hypertriglyceridemic waist (HTGW) phenotype (waist girth > 89 cm, triglyceride [TG] > 170 mg/dL) has been associated with the metabolic triad of elevated insulin, [Apo B], small dense low density lipoprotein cholesterol (LDL-C) and angiographically defined coronary heart disease (CHD) in a small sample of Caucasian men. The HTGW has not been reported for women, and the degree to which physical fitness (PF) modifies these associations between the HTGW and CHD risk factors is unknown. PURPOSE: To determine the prevalence of HTGW and the influence of PF on the relationship between HTGW and CHD risk among 137 healthy women (M ± SD, 54 ± 9 yr; 28 ± 6 kg/m2). METHODS: PF was quantified as total time during a maximal graded treadmill exercise test. Body mass index (BMI) was computed as weight (kg) ÷ height2 (m) and waist girth (cm) was measured level with the iliac crest. Standard automated assay procedures were used to determine fasting TG, Apo B and insulin concentrations. We defined the HTGW as waist girth > 88 cm and TG > 150 mg/dL. The metabolic triad was defined as higher than median levels of insulin (> 31pmol/L), Apo B (> 69 mg/dL) and LDL-C (> 84 mg/dL) among women with a BMI < 25. We computed the median Framingham 10-yr risk score (FRS; 4%) among women with BMI < 25 as a surrogate of future CHD risk. RESULTS: The sample prevalence of HTGW was 11%. Apo B (P = 0.04) and insulin (P = 0.0001) increased across quintiles of waist girth, and LDL-C (P = 0.004) increased across quintiles of TG. The prevalence of the metabolic triad was highest (67%) among women with TG > 150 mg/dL and waist > 88 cm, and lowest (22%) among women with TG < 150 mg/dL and waist < 88 cm. HTGW women had less favorable CHD risk factors than their non-HTGW counterparts. Among the HTGW group, fit (> 6.5 METs) women had more favorable CHD risk factors than unfit women. The odds of > 4% FRS among HTGW versus non-HTGW women was 2.8 (95% confidence interval [CI] = .78–8.5). Among the HTGW group, the odds of > 4% FRS among fit versus unfit women was 0.28 (95% CI = .02–3.5). CONCLUSIONS: HTGW exists in women and is associated with increased CHD risk as previously reported among men. PF favorably modifies associations between HTGW and CHD risk factors and should be considered in the clinical interpretation of HTGW and individual CHD risk. Supported by NIH WHI-SIP #22W-U48/CCU409664

Alcohol consumption and risk of coronary heart disease among men with type 2 diabetes mellitus

OBJECTIVESThe goal of this study was to examine the relationship between alcohol intake and risk of coronary heart disease (CHD) among men with type 2 diabetes.BACKGROUNDType 2 diabetes is associated with an increased risk of CHD. Emerging evidence suggests that moderate alcohol intake is associated with an important reduction in risk of CHD in individuals with type 2 diabetes.METHODSWe studied 2,419 men who reported a diagnosis of diabetes at age 30 or older in the Health Professionals’ Follow-up study (HPFS). During 11,411 person-years of follow-up after diagnosis, we documented 150 new cases of CHD (81 nonfatal myocardial infarction [MI] and 69 fatal CHD). Relative risks (RR) were estimated from pooled logistic regression adjusting for potential confounders.RESULTSAlcohol use was inversely associated with risk of CHD in men with type 2 diabetes. The age-adjusted RRs corresponding to intakes of ≤0.5 drinks/day, 0.5 to 2 drinks/day and >2 drinks/day were 0.76 (95% confidence interval: [CI]: 0.52 to 1.12), 0.64 (95% CI: 0.40 to 1.02) and 0.59 (95% CI: 0.32 to 1.09), respectively, as compared with nondrinkers (p for trend = 0.06). When we controlled for body mass index, smoking, family history of MI, hypertension, hypercholesterolemia, duration of diabetes, physical activity level, vitamin E supplements and intake of trans fat, polyunsaturated fat, fiber and folate, RRs were 0.78 (95% CI: 0.52 to 1.15), 0.62 (95% CI: 0.40 to 1.00) and 0.48 (95% CI: 0.25 to 0.94) (p for trend = 0.03). The benefits of moderate consumption did not statistically differ by beverage type.CONCLUSIONSModerate alcohol consumption is associated with lower risk of CHD in men with type 2 diabetes.

Treatment of dyslipidemia: genetic interactions with diet and drug therapy.

Coronary heart disease (CHD) is multifactorial, and its manifestation is determined by multiple gene loci and their interaction with a cohort of environmental factors. Variation at several candidate gene loci has already been shown to have a significant effect over the spectrum of plasma lipid levels observed in the population. Moreover, some variants are known to influence the interindividual variability in response to dietary and pharmacologic interventions aimed to reduce atherogenic lipoproteins. The continuous progress in this area of research is getting us closer to the development of genetic screening panels that will allow a more precise assessment of individual CHD risk and response to therapeutic interventions.

Effect of supplementation with vitamin E on LDL oxidizability and prevention of atherosclerosis.

Supplementation of LDL with vitamin E is thought to protect LDL from oxidative modification and prevent the development of atherosclerosis. Large epidemiological studies have revealed that vitamin E levels in plasma are inversely correlated to the incidence of coronary heart disease. Double-blind placebo-controlled trials have reported that supplementation with vitamin E decreases the incidence of coronary events in coronary heart disease (CHD) patients. However, it is not clear how high a dose of vitamin E is needed to prevent formation of atherosclerosis. In animal studies, a diet containing 0.125% vitamin E increased its levels in plasma two-fold and prevented formation of early atherosclerotic lesions in the thoracic aorta of hypercholesterolemic rabbits. Dose-response studies in humans have reported that 400 IU/day vitamin E increased its levels in plasma two-fold and prolonged the lag time before LDL oxidation. It has been reported that oxidizability of LDL was correlated to the atherosclerotic score of coronary angiography in CHD patients. About 400 IU/day vitamin E, which increases its levels two-fold and prolongs sufficiently the lag time before LDL oxidation, might be beneficial in decreasing the individual risk of CHD.

Teaching behavioral medicine using individual coronary heart disease risk factors

Two hundred twenty-one first-year medical students participated in a voluntary coronary heart disease risk factor self-change project designed to teach the principles of behavioral change. Blood pressure, serum lipids, percentage body fat, cardiovascular fitness, and smoking status were measured prior to the project. Students designed their own programs of behavior modification and, after 8 weeks, repeat measurements were obtained in students whose projects related to coronary heart disease risk (56% of entire group). Despite generally low initial coronary heart disease risk factors, most risk factor groups successfully altered the targeted risk factors. The subgroup attempting to lower serum cholesterol ( n = 49) reduced total cholesterol 15 ± 24 mg/dl (mean ± SD) and low-density lipoprotein cholesterol 11 ± 20 mg/dl ( P < 0.001 for both). The blood pressure group ( n = 9) decreased systolic blood pressure 8 ± 10 mm Hg ( P < 0.05), and the weight-loss group ( n = 33) lost 3.0 ± 2.9 kg ( P < 0.001), reducing estimated percentage body fat 1.7 ± 1.8 ( P < 0.001). The self-change project was well received by the students and appears to be a useful technique for introducing the principles of behavioral medicine to first-year medical students.