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Biomedical subjects

T A Pearson

Publications and source records attributed to T A Pearson.

At least 19 recordsLinked to original sources

Therapeutic management of triglycerides: an international perspective.

Current recommendations from various international expert committees generally concur in their definitions of borderline and high triglyceride levels, with small but important differences between recommendations in the definition of normal levels. However, population-based data on triglyceride levels are poorly developed in most countries, making difficult any international comparisons of prevalences of hypertriglyceridemia using the new definitions. However, it is probable that there should be considerable differences in the prevalence of hypertriglyceridemia, probably due to a mixture of genetic and environmental influences. The management of hypertriglyceridemia must continue to emphasize the detection and correction of secondary causes, even though the specific secondary causes may vary between countries. Dietary and exercise interventions must deal with local customs and resources, including striking international differences in alcohol consumption. Pharmacologic therapies will likely increase in use if they follow the trends in countries with available data. Although various drugs are available, nicotinic acid and fibric acid derivatives remain the drugs of choice. Considerably more research is needed to describe these international differences in etiology, prevalence and management practices of hypertriglyceridemia.

Humans

Prevalence and etiology of idiopathic dilated cardiomyopathy (summary of a National Heart, Lung, and Blood Institute workshop.

Idiopathic dilated cardiomyopathy (IDC) is the primary indication for cardiac transplantation, with associated costs of approximately $177 million per year. Recognizing the economic implications of IDC, the increasing incidence, and the limited information on pathogenesis and prognosis, the National Heart, Lung, and Blood Institute convened a workshop on the Prevalence and Etiology of Idiopathic Dilated Cardiomyopathy on June 13 to 14, 1991. The difficulties of studying the disease were reviewed, including its relatively low prevalence, its potentially pluricausal nature, and the fact that it is often a diagnosis of exclusion. Still, it presents significant challenges to the cardiovascular scientific community, since the mechanism of myocardial damage and related etiologic and prognostic factors are virtually unknown. The development of more reliable measures of immune-mediated damage and noninvasive measures of impaired cardiac function present new research opportunities in this disorder. Standardized diagnostic criteria for use in observational and interventional trials were developed, and priorities for future research were proposed. Population-based registries and nested case-control studies, where feasible, are appropriate study designs for tracking incidence and prevalence, and for identifying risk factors, respectively. Interventional studies should focus on secondary prevention, through modifying immune-mediated damage in clinically evident dilated cardiomyopathy, and through prevention of sudden death in patients with the disorder. Primary prevention trials must await the identification of modifiable risk factors and of appropriate and effective interventions.

Cardiomyopathy, Dilated

Comparison of the plasma levels of apolipoproteins B and A-1, and other risk factors in men and women with premature coronary artery disease.

The predictors of premature coronary atherosclerosis were examined in 203 patients (99 men aged less than or equal to 50 years, and 104 women aged less than or equal to 60 years) undergoing elective diagnostic coronary arteriography. Age, cigarette smoking, hypertension, obesity, diabetes, positive family history of premature coronary artery disease (CAD), and plasma levels of total cholesterol, triglyceride, lipoproteins (i.e., very low, intermediate-, low-, and high-density [HDL] lipoproteins and their subfractions [HDL2 and HDL3], and lipoprotein [a]) and apolipoproteins (apoA-1, apoA-2 and apoB, respectively) were examined using univariate analyses and multivariate logistic regression. In men, age (p less than 0.05), smoking (p less than 0.05), and plasma triglyceride (p less than 0.02) and apoA-1 (p less than 0.05) levels were independently associated with CAD. In women, smoking (p less than 0.001) and plasma apoB levels (p less than 0.04) were the strongest variables independently associated with CAD. It is concluded that the "nontraditional" risk factors (plasma apoA-1 and apoB levels) are better predictors of premature CAD than are plasma lipoproteins and that smoking is the strongest of the traditional nonlipid risk factors.

Adult

The effect of filtered-coffee consumption on plasma lipid levels. Results of a randomized clinical trial.

OBJECTIVE: --To determine the effect of filtered-coffee consumption on plasma lipoprotein cholesterol levels in healthy men. DESIGN: --Randomized controlled trial with an 8-week washout period followed by an 8-week intervention period during which men were randomly assigned to drink 720 mL/d of caffeinated coffee, 360 mL/d of caffeinated coffee, 720 mL/d of decaffeinated coffee, or no coffee. SETTING: --Outpatient clinical research center in a university medical center. PARTICIPANTS: --One hundred healthy male volunteers. OUTCOME MEASURE: --Changes in plasma lipoprotein cholesterol levels during the intervention period. RESULTS: --Men who consumed 720 mL of caffeinated coffee daily had mean increases in plasma levels of total cholesterol (0.24 mmol/L, P = .001), low-density lipoprotein cholesterol (0.17 mmol/L, P = .04), and high-density lipoprotein cholesterol (0.08 mmol/L, P = .03). No significant changes in these plasma lipoprotein levels occurred in the other groups. Compared with the group who drank no coffee the group who drank 720 mL/d of caffeinated coffee had increases in plasma levels of total cholesterol (0.25 mmol/L, P = .02), low-density lipoprotein cholesterol (0.15 mmol/L, P = .17), and high-density lipoprotein cholesterol (0.09 mmol/L, P = .12) after adjustment for changes in diet. CONCLUSION: --Consumption of 720 mL/d of filtered, caffeinated coffee leads to a statistically significant increase in the plasma level of total cholesterol, which appears to be due to increases of both low-density lipoprotein and high-density lipoprotein cholesterol levels.

Adult

Evaluation of random digit dialing as a method of control selection in case-control studies.

Control groups selected by random digit dialing are frequently used in case-control studies. Concern about the potential for bias in these control groups has been expressed, primarily because of low response rates. This study compares the characteristics of a hypothetical control group consisting of 341 men and women aged 40-74 years, selected by random digit dialing and participating in an interview in 1990, with the characteristics of 15,563 men and women aged 40-74 years who participated in a privately conducted census in the same upstate New York county in 1989. For most measures, no differences were seen between the random digit dialing sample and the census population. However, the hypothetical control group was more likely to have had their cholesterol checked in the past 2 years and was somewhat more likely to have had other screening tests as well. In addition, the hypothetical control group was somewhat better educated. The results suggest that, at least in this setting, control groups selected by random digit dialing are representative of the general population in most respects; however, caution should be used when studying the relation between screening tests and disease occurrence by means of case-control studies using controls selected by random digit dialing.

Adult

Long-term predictors of subsequent cardiovascular events with coronary artery disease and 'desirable' levels of plasma total cholesterol.

BACKGROUND: Patients with coronary artery disease (CAD) are at considerable risk for subsequent cardiovascular events. Although hyperlipidemia accentuates the risk, predictors of subsequent events with CAD and desirable total cholesterol (TC) (less than 5.2 mmol/l) have not been assessed. METHODS AND RESULTS: A survival analysis was performed in a subset of 740 consecutive patients who underwent diagnostic coronary arteriography between 1977 and 1978. Eight-three men and 24 women with angiographically documented CAD and desirable TC were followed for subsequent cardiovascular events, including myocardial infarction and cardiovascular death. Over a 13-year period, 75% of CAD subjects with reduced high density lipoprotein cholesterol (HDL-C) (less than 0.9 mmol/l) developed a subsequent cardiovascular event compared with 45% of those with HDL-C greater than or equal to 0.9 mmol/l (p = 0.002). A Kaplan-Meier analysis revealed significantly greater survival from cardiovascular end points in patients with baseline levels of HDL-C greater than or equal to 0.9 mmol/l (p = 0.005). After 11 variables were tested, an age-adjusted Cox proportional-hazards model identified two pairs of independent predictors of subsequent cardiovascular events: they were a left ventricular ejection fraction (LVEF) less than 35% (relative risk [RR], 6.5; 95% confidence interval [CI], 2.8, 15.3; p less than 0.001) and reduced HDL-C (RR, 2.0; 95% CI, 1.2, 3.3; p = 0.01) in the first model and LVEF less than 35% (RR, 6.5; 95% CI, 2.7, 15.6; p less than 0.001) and TC:HDL ratio greater than or equal to 5.5 (RR, 1.9; 95% CI, 1.1, 3.1; p = 0.02) in the second model. CONCLUSIONS: Low HDL-C (or high TC:HDL-C) is strongly predictive of subsequent cardiovascular events in subjects with CAD, despite desirable TC. As such, identification of this potentially modifiable risk factor should be actively pursued in this high-risk subgroup.

Adult

Invited commentary: should arteriographic case-control studies be used to identify causes of atherosclerotic coronary artery disease?

Arteriographic case-control studies still have a role in defining associations and dose-response relations between newly purported risk factors and atherosclerotic coronary artery disease. They remain one of the better ways to sort out whether a risk factor acts to cause clinical coronary disease via effects on coronary atherosclerosis, infarction independent of atherosclerosis, or both. It remains unclear if the selection processes for coronary arteriography infuse bias into the selection of cases, though the report by Reed and Yano suggests it does not. Control group selection remains problematic, as it does for all case-control studies, and considerable effort should be exercised to avoid the many potential biases in selection of both cases and controls. In this latter statement there is agreement with authors Reed and Yano. However, the avoidance of arteriographic studies threatens to curb the initiation of that sequence of studies that can, in a relatively short duration of time, provide useful information on the potential for a risk factor intervention to inhibit coronary atherosclerosis and, possibly, clinical coronary events. This, then, raises the final point for emphasis. Arteriographic studies, be they case-control, prospective, or experimental, may be most powerful when paired with those using clinical endpoints. In addition to the chance for replication of findings with another set of endpoints, the issue of mechanism of action via the atherosclerotic process can be addressed. Interestingly, the Honolulu Heart Program, with its laudable efforts to collect both autopsy and arteriographic quantitations of atherosclerosis, provides perhaps the best illustration in the current literature of the power of using multiple endpoints for coronary artery disease to more completely elucidate the role of risk factors in the natural history of that disease.

Angiography

Alcohol and atherosclerosis.

Considerable progress has been made in recent years in our understanding of atherogenesis and, in particular, of how it relates to lipoprotein metabolism. In this conference, we attempt to re-evaluate the data on the relation between alcohol intake and coronary heart disease, emphasizing the effects of alcohol on lipoprotein metabolism. Epidemiologic data generally show an inverse correlation between coronary heart disease risk and moderate alcohol intake (variously defined but generally corresponding to 2 to 4 drinks per day). The potentially drastic effects of excessive alcohol intake on health, however, preclude any recommendation that patients increase their alcohol consumption. Equally, there may be no basis for prescribing moderate alcohol intake but, even here, the data are far from complete. The mechanism by which moderate alcohol intake "protects" remains unclear. Perhaps the best available hypothesis relates to the increased concentration of high-density lipoprotein (HDL) cholesterol associated with moderate alcohol intake. However, it should be stressed that we are still uncertain about the mechanisms linking a high HDL level to protection against coronary heart disease. If a high HDL level is only a marker (and not directly protective), raising HDL levels need not confer protection. Alcoholism, on the other hand, is associated with marked elevation of triglyceride-rich lipoproteins and is among the most common causes of hypertriglyceridemia. Moreover, once hepatic damage occurs, plasma HDL levels may actually be lower than normal. The determining point is that high alcohol intakes are associated with increased overall mortality. Until we know more about the metabolic and behavioral effects of alcohol and about its linkage to atherosclerosis, we have no basis for recommending either that patients increase their alcohol intake or that they start to drink if they do not already.

Alcohol Drinking

Prevention of coronary heart disease in black adults.

Development of strategies to prevent CHD in blacks is impeded by the virtual absence of clinical trials demonstrating the feasibility and effectiveness of interventions in blacks. The wholesale generalization that interventions effective (or ineffective) in whites are similarly effective in blacks may risk the employment of worthless or even dangerous interventions in blacks. Using available epidemiologic data, a number of risk factors may be more important in blacks than whites by virtue of higher prevalence, increased relative risk, or both. These may include hypertension, lipoprotein (a), smoking, diabetes, and obesity. Thus, health agencies might emphasize these risk factors when developing preventive programs targeted at black populations. Prevention programs may best seek to prevent the onset of risk factors found highly prevalent in black communities, rather than the costly and side-effect-prone interventions to treat risk factors once established. Thus, there is a role for community-based as well as a high-risk approaches. The community-based approaches should seek to work with organizations such as churches, which traditionally play strong roles in the black community. Physicians treating black patients should be aware of the potentially different roles played by risk factors, and treat aggressively those individuals identified to be at high risk. Risk factor management should be emphasized, rather than reduced, in patients with already established CHD. CHD has been clearly shown to be preventable; both blacks and whites should benefit from specific interventions aimed toward this worthy goal.

Adult

Dyslipidemias with desirable plasma total cholesterol levels and angiographically demonstrated coronary artery disease.

The National Cholesterol Education Program treatment guidelines define a plasma total cholesterol of less than 200 mg/dl as "desirable" and recommend no further evaluation of plasma lipid or lipoprotein levels in patients with coronary artery disease (CAD). To determine the prevalence of dyslipidemias in the presence of coexistent CAD and total cholesterol less than or equal to 200 mg/dl, a retrospective case-control study of 1,000 patients who underwent diagnostic coronary angiography was performed. Of 351 patients with total cholesterol less than or equal to 200 mg/dl, 76% of the men (244) and 44% of the women (107) had angiographically demonstrated CAD. In men with CAD and total cholesterol less than or equal to 200 mg/dl, there was a significantly greater prevalence of low levels of high density lipoprotein (HDL) cholesterol (less than or equal to 35 mg/dl), age greater than 50 years, systemic hypertension and diabetes mellitus compared to non-CAD control subjects. In women with CAD and total cholesterol less than or equal to 200 mg/dl, HDL cholesterol less than or equal to 45 mg/dl and diabetes mellitus were also significantly prevalent. Multiple logistic regression analyses revealed that HDL cholesterol, hypertension and age in men and very low density lipoprotein cholesterol in women were significantly associated with CAD after adjustment for other risk factors. These results suggest that a complete lipid and lipoprotein analysis be obtained in all patients with CAD, irrespective of the plasma (or serum) total cholesterol level.

Adult

Youthful precursors of alcohol abuse in physicians.

PURPOSE: This study was designed to determine youthful precursors of alcohol abuse in physicians. SUBJECTS AND METHODS: We analyzed data from an ongoing prospective study of 1,014 male medical students enrolled in the graduating classes of 1948-1964 at the Johns Hopkins School of Medicine. The cohort, now physicians aged 52 to 68 years, has been contacted regularly since medical school to identify major disease. In 1986, the CAGE alcoholism screening questionnaire was administered. Alcohol abuse was defined as self-admitted alcoholism, excessive consumption of four or more beverages per day on average, or a score of 2 or higher on the CAGE questionnaire. RESULTS: By these criteria, 131 of 1,014 (12.9%) patients abused alcohol. Medical school precursors associated (p less than 0.05) with subsequent alcohol abuse were as follows: non-Jewish ancestry (relative odds [RO] = 3.1), lack of religious affiliation (RO = 4.1), cigarette use of one pack or more per day (RO = 2.6), regular use of alcohol (RO = 3.6), anxiety (RO = 1.8) or anger (RO = 1.8) as a reaction to stress, frequent use of alcohol in nonsocial settings (RO = 1.6), past history of alcohol-related difficulty (RO = 3.1), and maternal alcoholism or mental illness (RO = 1.9). Precursors found not to be associated with alcohol abuse included sleep habits, use of sedatives or amphetamines, interest in athletics or hobbies, and parental relationship. CONCLUSION: Our results suggest that there are several identifiable medical school precursors of alcohol abuse in physicians.

Adult

Plasma dehydroepiandrosterone and dehydroepiandrosterone sulfate in patients undergoing diagnostic coronary angiography.

Serum levels of DHEA sulfate are inversely associated with cardiovascular death in men, and urinary dehydroepiandrosterone (DHEA) levels are inversely associated with clinical manifestations of coronary artery disease. These observations may be related to the antiproliferative effects of DHEA, resulting in inhibition of atherosclerotic intimal hyperplasia. To examine the relation between these steroids and a direct measure of coronary atherosclerosis, plasma DHEA and DHEA sulfate levels were determined in 206 middle-aged patients (103 men, 103 women) undergoing elective coronary angiography. Plasma DHEA sulfate levels were lower in men with at least one stenosis greater than or equal to 50% compared with those without any stenosis greater than or equal to 50% (4.9 +/- 2.7 versus 6.1 +/- 3.5 nmol/ml, p = 0.05). Levels of DHEA sulfate were also inversely related to the number of diseased coronary vessels (r = -0.20, p = 0.05) and a continuous measure of the extent of coronary atherosclerosis (r = -0.25, p = 0.01) in men. The association between DHEA sulfate levels and extent of coronary artery disease was independent of age and other conventional risk factors for coronary disease. In women, there was no association between plasma DHEA or DHEA sulfate levels and coronary disease. These data demonstrate a consistent, independent, inverse, dose-response relation between plasma DHEA sulfate levels and angiographically defined coronary atherosclerosis in men. Plasma DHEA sulfate may be another important and potentially modifiable risk factor for the development and progression of coronary atherosclerosis.

Adult

The epidemiology of idiopathic dilated cardiomyopathy in a biracial community.

An epidemiologic study of idiopathic dilated cardiomyopathy was carried out in order to identify possible risk factors for this often fatal cause of heart failure in young adults. Possible associations with black race and other genetic and environmental factors were examined by comparing newly diagnosed cases ascertained from four Baltimore hospitals (n = 95) with neighborhood controls (n = 95), matched on sex and 5-year age intervals. Matched and unmatched relative odds and conditional logistic regression coefficients were obtained to describe the associations. Statistically significant, independent associations were observed between idiopathic dilated cardiomyopathy and black race, low annual income, and history of asthma (p less than 0.05). The black predominance (relative odds = 2.7, 95% confidence interval 2.0-3.4) was not explained by income, alcohol consumption, cigarette usage, body mass index, hypertension, or asthma. A possible interactive effect was observed between black race and history of asthma and other atopic diseases. Thus, blacks, especially those with a history of hypersensitivity, may represent a high-risk subgroup in need of preventive care or early intervention.

Adolescent