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Biomedical subjects

R D Abbott

Publications and source records attributed to R D Abbott.

At least 73 records · Page 4Linked to original sources
PubMed1996

Plasma fibrinogen and coronary heart disease in elderly Japanese-American men.

Clinical and epidemiological studies consistently indicate that elevations in plasma fibrinogen concentration are associated with the presence and development of coronary heart disease (CHD). These elevations are strongly correlated with smoking behavior and may play a significant role in mediating a relation of smoking to CHD. This cross-sectional survey of 3571 elderly Japanese-American men, aged 71 through 93 years, represents survivors of the Honolulu Heart Program cohort. Active smokers are almost twice as likely to be represented in the highest quintile of the fibrinogen distribution compared with the lowest quintile (9.8% versus 5.3%, respectively). The highest prevalence of CHD (34%) was noted in past and current smokers who were in the highest quintile of fibrinogen. The age-adjusted relative odds of prevalent CHD comparing the average fibrinogen levels in the first and fifth quintiles were 1.36 (95% confidence interval, 1.13 to 1.64). After adjustment for smoking status, blood pressure, total and HDL cholesterol, diabetes status, hematocrit, and white cell count, the association between fibrinogen and CHD was changed slightly and remained statistically significant (P < .05). These findings in an elderly cohort of Japanese-American men are consistent with previous studies among middle-aged adults demonstrating fibrinogen to be associated with indicators of clinical CHD and CHD risk factors. Because of the cross-sectional nature of this study, it is not possible to distinguish whether the observed relation of fibrinogen to prevalent CHD is causal or whether it represents a marker of active and progressive disease.

Age Distribution↗
PubMed1996

Effect of dietary calcium and milk consumption on risk of thromboembolic stroke in older middle-aged men. The Honolulu Heart Program.

BACKGROUND AND PURPOSE: Evidence suggests that dietary calcium is protective against hypertension. This report examines whether the effect has an influence on thromboembolic stroke. METHODS: Since 1965, the Honolulu Heart Program has followed a cohort of men in a study of cardiovascular disease. This report examines the effect of baseline dietary calcium and milk intake on stroke risk in 22 years of follow-up in 3150 older middle-aged men (55 to 68 years). RESULTS: Men who were nondrinkers of milk experienced stroke at twice the rate (P < .05) of men who consumed 16 oz/d or more (7.9 versus 3.7 per 100, respectively). While the rate of stroke decreased with increasing milk intake (P < .05), the decline in stroke risk with increased consumption was modest for those who consumed under 16 oz/d. Intake of dietary calcium was also associated with a reduced risk of stroke (P < .01), although its association was confounded with milk consumption. Calcium intake from nondairy sources was not related to stroke, suggesting that other constituents or covariates related to milk consumption may be important. CONCLUSIONS: We conclude that an association between milk consumption and a reduced risk of stroke in older middle-aged men cannot be explained by intake of dietary calcium. Since milk is often part of a diverse pattern of dietary intake, it is difficult to determine whether milk consumption has a direct role in reducing the risk of stroke. Data suggest that consumption of milk in older middle age is not harmful, and when combined with a balanced diet, weight control, and physical activity, reductions in the risk of stroke may occur.

Age Factors↗
PubMed1996

Age-related changes in stroke risk in men with hypertension and normal blood pressure.

BACKGROUND AND PURPOSE: Stroke is a major contributor to total morbidity and mortality in older individuals, and hypertension is an important risk factor for stroke. Relatively few data exist on whether this relationship changes with age. METHODS: To examine age-related changes in the relationships between risk of stroke and hypertension, we examined the 6-year incidence of stroke among men aged 45 to 81 years using updated blood pressure data from three examinations of Japanese-American men from the Honolulu Heart Program. RESULTS: Both the prevalence of hypertension (systolic blood pressure > or = 160 mm Hg or diastolic blood pressure > or = 95 mm Hg or the use of antihypertensive medication) and the 6-year incidence of stroke increased significantly with increasing age (P < .01). The increase in thromboembolic stroke incidence with age was more marked in those who were normotensive at baseline (2.7/1000 in those aged 45 to 54 years to 23.9/1000 in those > or = 65 years; P < .001) than in hypertensive men (20.6/1000 in those aged 45 to 54 years to 33.5/1000 in those > or = 65 years; P < .01). The age-related increase in risk of thromboembolic stroke among normotensive men resulted in a decrease in the percentage of strokes attributable to hypertension (50% in those aged 45 to 54 years to 18% in those > or = 65 years; P < .05). Similar trends were seen for hemorrhagic stroke. There were no age-related changes in the relationships of other major atherosclerotic risk factors with stroke. The hypertension/stroke relationships were present after multivariate adjustment for age, smoking, cholesterol, and other factors. CONCLUSIONS: In view of the greater prevalence of hypertension and the proven efficacy of treatment in the elderly, these findings do not negate the value of aggressive screening and treatment of hypertension in this age group. However, it appears that other unidentified factors have an increasing role in the causation of stroke with advancing age.

Age Factors↗
PubMed1995

Sudden death, impaired glucose tolerance, and diabetes in Japanese American men.

BACKGROUND: Diabetes and glucose intolerance have been shown to increase the risk of cardiovascular mortality in a number of different populations. Most studies have been based on short follow-up periods, and few have had sufficient numbers to allow researchers to look at sudden death as an outcome. METHODS AND RESULTS: The relation of sudden death, defined as unexpected death occurring within either 1 or 24 hours of first symptoms, to glucose intolerance measured by a nonfasting 1-hour postload measurement made in 1965 or history of diabetes was examined by use of 23 years of follow-up on the 8006 participants enrolled in the Honolulu Heart Program. After adjustment for baseline body mass index, hypertension, cholesterol, triglycerides, smoking, alcohol consumption, and left ventricular hypertrophy or strain, the relative risks for sudden death within 24 hours in individuals with high-normal (151 to 224 mg/dL), asymptomatic high glucose values (> or = 225 mg/dL), and diabetes compared with those with lower glucose values (< 151 mg/dL) were 1.59, 2.22, and 2.76, respectively. All these relative risks were statistically significant (P < or = .05). Trends for sudden death in 1 hour were similar. Among men with sudden death < 1 hour after onset of symptoms, the strength of the association between diabetes and sudden death was stronger among those classified as having died of unknown causes who thus were more likely to have died of an arrhythmia than among those classified as having died of coronary heart disease. CONCLUSIONS: The relations seen in these analyses indicate that individuals with glucose intolerance or diagnosed diabetes are at increased risk for sudden death.

Aged↗
PubMed1995

Low yield of transthoracic echocardiography for cardiac source of embolism.

To test the hypothesis that the yield for a cardiac source of embolism is very low using transthoracic echocardiography, we reviewed the echocardiographic reports of 1,010 consecutive patients with cerebrovascular accidents who had undergone echocardiography to rule out a cardiac source of embolism; risk factor information was also available in 493 patients. We also used 325 controls who had undergone echocardiography for other reasons during the same period. Each report was examined for the presence of predefined findings depending on their propensity for causing cerebrovascular accidents via an embolic process. The prevalence of a highly probable source of embolism was low in cases (< 3%) and no different from controls after adjusting for age and other risk factors. The prevalence of a possible cardiac source of embolism was also low (< 5%) and similar in cases and controls. The presence of definite or possible thrombus on echocardiography resulted in alteration in therapy in only 2% of cases, of whom 77% had either heart failure, atrial fibrillation, or Q waves on the electrocardiogram. We conclude that the yield of highly probable or possible cardiac source of embolism in patients with cerebrovascular accidents is very low with transthoracic echocardiography, and is no higher than that noted in similar patients without cerebrovascular accidents.

Adult↗
PubMed1995

Reduction of femoral arterial bleeding post catheterization using percutaneous application of fibrin sealant.

The number of cardiac catheterizations performed yearly is growing with correspondingly increasing amounts of morbidity, complications, and hospital costs. This study suggests that fibrin sealant instillation via an arterial sheath at the completion of femoral catheterization may improve hemostasis. Results using fibrin sealant in 12 unheparinized dogs documented significant reductions (McNemar's exact test) versus control for groin ecchymoses (1 versus 8, P = .008) and radiolabeled hematoma formation (0 versus 7, P = .016). Also swelling was less in the fibrin sealant treated groins when compared to control groins (1 versus 6, P = .125), but failed to reach statistical significance. Results in eight heparinized dogs (activated clotting time 374 +/- 22, mean +/- SEM) revealed a statistically significant reduction in signs of gross bleeding in the fibrin sealant-treated groins (1 versus 8, P = .016). This method may contribute to reduced morbidity, complications, and length of hospitalization. It may also allow for earlier patient mobilization after cardiac catheterization.

Administration, Cutaneous↗
PubMed1995

Predicting serious delinquency and substance use among aggressive boys.

Early aggressive behavior puts boys at increased risk for involvement in a variety of later problem behaviors, including delinquency and drug abuse. However, not all boys who evidence aggressive behavior in childhood continue to engage in problem behaviors in adolescence. This 3.5-year prospective study examined the role of factors hypothesized by the social development model to inhibit or increase the likelihood of subsequent involvement in serious delinquency and substance use within a sample of boys identified as aggressive by teacher report at ages 10 and 11. At ages 12 and 13, a combination of the constructs of skills for prosocial involvement, school bonding and achievement, family bonding and management practices, norms against substance use, and interaction with peers and adults involved in antisocial behavior significantly discriminated between boys who were and were not involved in serious delinquent behavior and substance use at ages 13 and 14, although family bonding and management practices appeared to contribute little to the discriminant function. Implications of the results for preventive interventions with aggressive boys are discussed.

Adolescent↗
PubMed1995

Preventing school failure, drug use, and delinquency among low-income children: long-term intervention in elementary schools.

A six-year, school-based prevention program, which modified classroom teacher practices, offered parent training, and provided child social skills training, was evaluated for its effects on school failure, drug abuse, and delinquency among low-income urban children. Compared to a low-income control group, children in the intervention group showed enhanced school commitment and class participation. The girls in the group also evidenced lower rates of substance use initiation, while the boys exhibited increased social and school work skills.

Adolescent↗
PubMed1995

General surgical complications can be predicted after cardiopulmonary bypass.

OBJECTIVE: The authors review the general surgical complications of cardiopulmonary bypass, including newer procedures such as heart and lung transplantation, to identify patients at higher risk. SUMMARY BACKGROUND DATA: Although rare, the general surgical complications of cardiopulmonary bypass are associated with high mortality. The early identification of patients at increased risk for these complications may allow for earlier detection and treatment of these problems to reduce mortality. METHODS: A retrospective review was performed of 1831 patients undergoing cardiopulmonary bypass from 1991 to 1993. This was done to identify factors that significantly contributed to an increased risk of general surgical complications. RESULTS: Factors associated with an increased risk of general surgical complications included prolonged cardiopulmonary bypass (p < 0.005) and intensive care unit stay (p < 0.002), occurrence of arrhythmias (p < 0.001), use of inotropic agents (preoperatively or postoperatively p < 0.001), insertion of the intra-aortic balloon pump (preoperatively p < 0.005, postoperatively p < 0.001), use of steroids (p < 0.001), and prolonged ventilator support (p < 0.001). Multivariate analysis identified use of the intra-aortic balloon pump (p < 0.001) as the strongest predictor of the general surgical complications of cardiopulmonary bypass. A variety of factors not contributing significantly to an increased risk also were identified. CONCLUSIONS: Factors indicative of or contributing to periods of decreased end-organ perfusion appear to be significantly related to general surgical complications after cardiopulmonary bypass.

Aged↗
PubMed1994

Physical activity in older middle-aged men and reduced risk of stroke: the Honolulu Heart Program.

From 1965 to 1968, the Honolulu Heart Program began following 8,006 men in a prospective study of cardiovascular disease. At the time of study enrollment, an estimate of current 24-hour habitual physical activity was collected from each subject. On the basis of a calculated physical activity index, subjects were classified as being inactive, partially active, or active. This report examines the relation between the levels of physical activity and stroke that occurred among 7,530 of the men over 22 years of follow-up. Risk of stroke was examined separately in younger (45-54 years) middle-aged men and older (55-68 years) middle-aged men. Among the older men, those who were inactive or partially active experienced a three- to fourfold excess incidence of hemorrhagic stroke as compared with active men (p < 0.01). There was a two- to threefold excess of intracerebral hemorrhage in men who were inactive or partially active as compared with those who were active (p < 0.05). An excess of subarachnoid hemorrhage was observed in inactive older men, with only one event occurring in those who were active (p < 0.05). After exclusion of subjects with hypertension, diabetes mellitus, and left ventricular hypertrophy, the relative risk of hemorrhagic stroke for inactive men versus active men was 3.7 (95% confidence interval (CI) 1.3-10.4). In older men who did not smoke cigarettes, the relative risk of thromboembolic stroke among inactive men versus active men was 2.8 (95% CI 1.2-6.7), and when partially active older men were compared with those who were active, the relative risk was 2.4 (95% CI 1.0-5.7). These findings persisted after control for the residual effects of systolic blood pressure and other risk factors for stroke. Benefits of physical activity in reducing the risk of thromboembolic stroke were not observed in men who smoked cigarettes. The authors conclude that physical activity may be important in reducing the risk of stroke, particularly among nonsmoking men in older middle age.

Aged↗
PubMed1994

Effect of inhalation of hot humidified air on experimental rhinovirus infection.

OBJECTIVE: Nasal inhalation of steam has been proposed as treatment of viral colds on the assumption that increased intranasal temperature will inhibit replication of rhinovirus (RV). The effect of steam inhalation on RV shedding by infected volunteers was examined in this study. DESIGN: Randomized controlled trial. Volunteers experimentally infected with RV were treated with machine-generated humidified air, which was either hot (active) or at room temperature (placebo). Viral shedding was assessed over the 4 days following treatment. SETTING: Local hotel. PARTICIPANTS: Twenty volunteers from the university community who were susceptible to the challenge virus. INTERVENTION: Two 30-minute intranasal treatments, the first at 24 hours after inoculation and the second at 48 hours. The temperature of active vapor was 42 degrees C to 44 degrees C and of placebo vapor was 22 degrees C. MAIN OUTCOME MEASURES: Viral titers in nasal washings on each of 5 days following inoculation. RESULTS: Mean viral titers prior to the first treatment were 10(1.7) tissue culture infectious doses per milliliter in the active group and 10(1.5) in the placebo group. Mean titers for the next 4 days were 10(1.7), and 10(1.7), 10(1.2), and 10(0.9)/mL in the active group and 10(1.8), 10(1.9), 10(1.6), and 10(0.7)/mL in the placebo group (no significant difference). The proportion of volunteers who shed virus on each day was also similar in the two groups. CONCLUSION: Two nasal inhalation treatments with steam had no effect on viral shedding in volunteers with experimental RV colds.

Administration, Inhalation↗
PubMed1994

Physical activity and 23-year incidence of coronary heart disease morbidity and mortality among middle-aged men. The Honolulu Heart Program.

BACKGROUND: The purpose of the study was to examine the association between physical activity and 23-year incidence of coronary heart disease morbidity and mortality. This cohort study continues to follow 8006 Japanese-American men who were 45 to 68 years of age and living on Oahu, Hawaii, in 1965, for the development of coronary heart disease morbidity and mortality. METHODS AND RESULTS: The Framingham physical activity index was calculated by summing the product of average hours spent at each activity level and a weighting factor based on oxygen consumption. Study subjects were divided into tertiles of physical activity index at baseline. Relative risks and 95% confidence intervals (CI) for incidence of coronary heart disease morbidity and mortality were obtained using the Cox model. After age adjustment and using the lowest physical activity index tertile as a reference group, the relative risk for coronary heart disease incidence for the highest tertile of physical activity was 0.83 (CI, 0.70 to 0.99). After adjusting for age, hypertension, smoking, alcohol intake, diabetes, cholesterol, and body mass index, the relative risk was 0.95 and CI included 1 (CI, 0.80 to 1.14). For coronary heart disease mortality, the age-adjusted relative risk was 0.74 (CI, 0.56 to 0.97) and 0.85 (CI, 0.65 to 1.13) after risk factor adjustment. CONCLUSIONS: The results suggest that the impact of physical activity index on coronary heart disease is mediated through its effects on hypertension, diabetes, cholesterol, and body mass index. These findings support the hypothesis that physical activity is inversely associated with coronary heart disease morbidity and mortality and suggest that physical activity interventions in middle-aged men, by improving cardiovascular risk factor levels, may have significant public health implications in the prevention of coronary heart disease.

Aged↗
PubMed1994

In vivo myocardial kinetics of air-filled albumin microbubbles during myocardial contrast echocardiography. Comparison with radiolabeled red blood cells.

Myocardial contrast echocardiography (MCE) is a new technique for assessing myocardial perfusion that uses intracoronary injections of microbubbles of air. Because these microbubbles have a mean diameter of 4.3 +/- 0.3 microns and an intravascular rheology similar to that of red blood cells (RBCs), we hypothesized that their mean myocardial transit rates recorded on echocardiography would provide an estimation of regional myocardial blood flow in the in vivo beating heart. Accordingly, blood flow to the left anterior descending coronary artery (LAD) of 12 open-chest anesthetized dogs (group I) was adjusted to 4 to 6 flows (total of 60 flows), and microbubbles and radiolabeled RBCs were injected into the LAD in a random order at each stage. The mean myocardial RBC transit rates were measured by fitting a gamma-variate function to time-activity plots generated by placing a miniature CsI2 probe over the anterior surface of the heart, and the mean myocardial microbubble transit rates were measured from time-intensity plots derived from off-line analysis of MCE images obtained during the injection of microbubbles. An excellent correlation was noted between flow (measured with an extracorporeal electromagnetic flow probe) and mean myocardial RBC transit rate (y = 2.83 x 10(-3)x + 0.01, r = .96, SEE = 0.02, P < .001). A close correlation was also noted between mean RBC and microbubble myocardial transit rates (y = 1.01x + 0.01, r = .89, SEE = 0.02, P < .001). Despite its theoretical advantages, a lagged normal density function did not provide a better fit to the MCE data than the gamma-variate function.(ABSTRACT TRUNCATED AT 250 WORDS)

Albumins↗
PubMed1994

Body mass index and thromboembolic stroke in nonsmoking men in older middle age. The Honolulu Heart Program.

BACKGROUND AND PURPOSE: While evidence suggests that obesity has an independent relation to coronary artery disease, similar findings for stroke have not been established. The purpose of this study was to examine the relation between body mass index and the risk of thromboembolic stroke independently of other risk factors. METHODS: Since 1965, the Honolulu Heart Program has followed a cohort of men in a prospective study of cardiovascular disease. This article examines the relationship between the baseline measurement of body mass index and the risk of thromboembolic stroke in 1163 nonsmoking men in older middle age (55 to 68 years). Men who had an elevated risk of stroke due to hypertension, diabetes, and other risk factors were excluded from the analysis. RESULTS: After 22 years of follow-up, the rate of stroke increased significantly with increasing levels of body mass (P < .01). In the bottom tertile of the body mass index, the rate of thromboembolic stroke was 28.7 per 1000 (11/383). In the middle tertile, the rate was increased by 40% to 40.7 per 1000 (16/393), and in the top tertile, the rate of thromboembolic stroke was 55.4 per 1000 (21/387), a twofold excess compared with the bottom tertile. After adjustment for age and the residual effects of confounding risk factors, including systolic blood pressure and serum glucose, the estimated relative risk of stroke for the average body mass index in the top tertile (26.6 kg/m2) compared with that in the bottom tertile (20.3 kg/m2) was 2.1 (95% confidence interval, 1.1 to 4.1). These findings were not affected by coronary events that occurred in the course of follow-up, nor did they appear to be influenced by deaths from other causes. CONCLUSIONS: We conclude that elevated body mass is associated with an increased risk of thromboembolic stroke in nonsmoking men in older middle age who are free of commonly observed conditions related to cardiovascular disease.

Age Factors↗
PubMed1994

Glucose intolerance and 22-year stroke incidence. The Honolulu Heart Program.

BACKGROUND AND PURPOSE: This study was conducted to determine whether glucose intolerance and diabetes increase the risk of thromboembolic, hemorrhagic, and total stroke independent of other risk factors. METHODS: Among 7549 Japanese-American men aged 45 to 68 years and free of coronary heart disease and stroke during 1965 to 1968, history of diabetes, diabetic medication, and nonfasting glucose 1 hour after a 50-g load were used to classify subjects into four glucose tolerance categories. Incidence of stroke over 22 years was ascertained using comprehensive hospital-based surveillance. Age- and risk factor-adjusted relative risks of stroke were determined using a Cox proportional hazards model. RESULTS: A total of 374 thromboembolic, 128 hemorrhagic, and 36 type-unknown strokes occurred. Incidence of thromboembolic but not hemorrhagic stroke increased with worsening glucose tolerance category. Compared with the "low-normal" (glucose < 151 mg/dL) group, subjects in the "high-normal" (151 to 224 mg/dL), "asymptomatic high" (> or = 225 mg/dL), and "known diabetes" groups all had significantly elevated age-adjusted relative risks of thromboembolic stroke. After adjustment for other risk factors, relative risks remained significantly elevated for the asymptomatic high and known diabetes groups (1.43 and 2.45; 95% confidence intervals, 1.00 to 2.04 and 1.73 to 3.47, respectively). Associations were the same in hypertensive and nonhypertensive subjects and similar but slightly stronger in younger (aged 45 to 54 years) than in older (aged 55 to 68 years) men. CONCLUSIONS: Subjects with diabetes and elevated glucose appear to be at increased risk of thromboembolic but not hemorrhagic stroke. These associations were largely independent of other cardiovascular disease risk factors. Excess risk is apparent in older as well as younger diabetic individuals and in hypertensive and nonhypertensive subjects with diabetes.

Aged↗
PubMed1994

Relationship between age, percentage body fat, fitness, and 24-hour growth hormone release in healthy young adults: effects of gender.

We investigated whether gender affects the physiological relationships between the release of GH and age, body composition, and levels of physical fitness in humans. We studied 32 eumenorrheic females (age = 31 +/- 5 yr) and 12 males (age = 27 +/- 5 yr). Significant gender differences were found for peak oxygen consumption [VO2 peak = 40.5 +/- 6.9 (females) vs. 50.1 +/- 11.6 (males) ml/kg.min-1, P < 0.05] and body composition [hydrostatic weighing, percentage body fat = 28.7 +/- 5.4 (females) vs. 18.1 +/- 9.8 (males), P < 0.05] but not for body mass index [BMI = 23.7 +/- 3.1 (females) vs. 24.0 +/- 3.3 (males)]. Blood samples were drawn every 10 min for 24 h from 0800 h to determine integrated serum GH concentration [2350 +/- 1260 (females) vs. 3110 +/- 1760 (males) microgram/L x min]; females were studied during the early follicular phase (days 4-5) of the menstrual cycle. In females, a significant relationship existed between 24-h integrated serum GH concentration and age (r = -0.35, P = 0.05) but not BMI (r = -0.19, P = 0.29); the relationship between 24-h integrated serum GH concentration and VO2 peak (r = 0.31, P = 0.08) and percentage body fat (r = 0.29, P = 0.11) approached significance. In males, significant relationships existed between 24-h integrated serum GH concentration and age (r = -0.79, P = 0.002), percentage body fat (r = -0.75, P = 0.005), and VO2 peak (r = 0.58, P = 0.05) but not between 24-h integrated serum GH concentration and BMI (r = -0.53, P = 0.08). Standardized regression coefficients revealed that for each SD change in age, BMI, percentage body fat, or VO2 peak the associated change in 24-h integrated serum GH concentration was 1.9-2.6 times greater in males than in females. We conclude that age, percentage body fat (but not BMI), and fitness are related to 24-h GH release in young adults and that these relationships are considerably stronger in males than females.

Adipose Tissue↗