Biomedical subjects

Gregory W Evans

Publications and source records attributed to Gregory W Evans.

24 records · Page 2Linked to original sources

PubMed2002

Impact of body mass index on changes in common carotid artery wall thickness.

OBJECTIVE: To examine associations between changes in body mass index (BMI) and changes in carotid artery intima-media thickness (IMT) in a community-based sample. RESEARCH METHODS AND PROCEDURES: Carotid artery IMT and BMI were assessed at baseline (between 1987 and 1990) and in three subsequent examinations at 3-year intervals in participants in the Atherosclerosis Risk in Communities cohort. The 9,316 African-American and white men and women in the analysis were 45 to 64 years of age at baseline. Cross-sectional associations between BMI and IMT were assessed using general linear models. Longitudinal associations were examined using mixed models analysis. RESULTS: Cross-sectional associations between BMI and IMT were confirmed. At baseline, a 1-kg/m(2) increase in BMI was associated with an increase in IMT that ranged from 2.5 to 7.5 micro m among the ethnic-gender groups examined. Changes in BMI were not associated with changes in IMT in models that adjusted for aging and other covariates. Results were similar across ethnic-gender groups. DISCUSSION: Among free-living, 45- to 64-year-old adults, changes in common carotid artery IMT associated with changes in BMI are either very small or absent.

Aged↗

PubMed2002

Correlates of the shift in heart rate variability with an active postural change in a healthy population sample: The Atherosclerosis Risk In Communities study.

BACKGROUND: The heart rate variability (HRV) response to postural change is a sensitive measure of the shift in autonomic balance from parasympathetic to sympathetic predominance that, when attenuated or absent, has been correlated with prevalent disease in patient populations. In a healthy population sample, we evaluated whether the shift in HRV with postural change differed by demographic characteristics as well as whether it differed between participants with established coronary heart disease (CHD) risk factors and their counterparts. METHODS: HRV was measured for 2 minutes in the supine and standing positions in a biracial sample of men and women (aged 45-64 years) without clinical CHD from the Atherosclerosis Risk In Communities Study (n = 7686). Mean differences among supine and standing mean R-R interval lengths, the SD of R-R intervals, and high-frequency power (HF) were compared by demographic characteristics (age, race, and sex) and CHD risk factors (smoking, obesity, physical activity, hypertension, and diabetes). Multivariable linear regression models were used to adjust for demographic characteristics. RESULTS: Smaller changes in R-R intervals and larger changes in SD of R-R intervals with standing were found among participants who were obese, less physically active than their counterparts, hypertensive, and diabetic. Smaller changes in HF were identified in male and white participants, but there were no differences in HF by CHD risk factors once models were adjusted for demographic characteristics. CONCLUSIONS: These simple noninvasive measures can be used to detect differences in cardiac autonomic balance that may be markers for autonomic impairment in healthy adults.

Age Factors↗

PubMed2002

Lower heart rate variability is associated with the development of coronary heart disease in individuals with diabetes: the atherosclerosis risk in communities (ARIC) study.

The objective of this study was to test prospectively in a population sample whether individuals with impaired heart rate variability (HRV) are at increased risk of developing coronary heart disease (CHD) and of non-CHD mortality and to test whether this relationship is more pronounced among individuals with diabetes. We examined the association between HRV and incident CHD and non-CHD mortality in a cohort of 11,654 men and women aged 45-64 years at intake, from the biracial, population-based Atherosclerosis Risk in Communities Study. Supine, resting, 2-min beat-to-beat heart rate data were collected at the baseline examination. High frequency (HF; 0.15-0.40 Hz) and low frequency (LF; 0.04-0.15 Hz) spectral powers, LF/HF ratio, normalized HF and LF, the standard deviation of all normal R-R intervals (SDNN), and the mean of the sum of the squared differences between adjacent normal R-R intervals (MSSD) were used as the conventional indexes of HRV to measure cardiac autonomic control. From this cohort, 635 cases of incident CHD (including 346 cases of incident myocardial infarction [MI] and 82 cases of fatal CHD), and 623 non-CHD deaths were identified and validated after an average of 8 years of follow-up. Among individuals with diabetes, the multivariable adjusted proportional hazards ratios (95% CI) were 2.03 (1.28-3.23), 1.60 (1.12-2.27), 1.50 (0.65-3.42), and 1.27 (0.84-1.91) for incident MI, incident CHD, fatal CHD, and non-CHD deaths, respectively, comparing the lowest quartile to the upper most three quartiles of HF. A similar pattern of associations was found for LF, SDNN, and MSSD. By contrast, there was no consistent pattern of associations among individuals without diabetes. At the population level, a lower HRV (reflective of impaired cardiac autonomic control) is statistically significantly related to the development of CHD among individuals with diabetes, independent of markers of the duration/severity of the glucose metabolism impairment. These data suggest a contribution of an impaired cardiac autonomic control to the risk of CHD among individuals with diabetes.

Autonomic Nervous System↗

PubMed2002

Vasectomy, inflammation, atherosclerosis and long-term followup for cardiovascular diseases: no associations in the atherosclerosis risk in communities study.

PURPOSE: Although human studies have failed to reveal an increased risk of clinical cardiovascular disease in men who undergo vasectomy, the possibility exists that an association may be detectable only after a long followup, or it may be more evident for subclinical than clinical disease. We assessed the association of vasectomy with inflammation and coagulation factors, carotid intimal-medial thickness, carotid plaque, prevalent peripheral arterial disease, and incident coronary heart disease and stroke in the Atherosclerosis Risk in Communities cohort. MATERIALS AND METHODS: Included in the study were 3,957 white men 45 to 64 years old who were free of coronary heart disease at the Atherosclerosis Risk in Communities (ARIC) baseline examination in 1987 to 1989. Data on vasectomy was collected at baseline by self-reporting. High resolution B-mode ultrasound was done to assess carotid intimal-medial thickness and carotid plaque. The cohort was followed an average of 9 years for incident cardiovascular events. RESULTS: Average time since vasectomy was 16 years. Approximately 20% of the population had undergone vasectomy 20 years or more ago at baseline. Multivariate analysis showed no association of vasectomy status with inflammation or coagulation factors, peripheral arterial disease, carotid plaque, carotid far wall thickness, incident coronary heart disease or stroke. Associations were unaffected by the time since vasectomy. CONCLUSIONS: There is no evidence in this population based sample of men indicating that vasectomy is related to atherosclerosis even after more than 20 years of followup.

Adult↗

PubMedDate not supplied

Association of traditional and nontraditional cardiovascular risk factors with coronary artery calcification.

Coronary artery calcification assessed by computed tomography is an emerging marker of coronary atherosclerosis. The authors examined the association of coronary calcium scores with traditional and nontraditional cardiovascular risk factors. In 1999-2000, they measured coronary artery calcium in 360 participants free of known coronary artery disease who had participated in 2 centers of the Atherosclerosis Risk in Communities (ARIC) Study. They related coronary calcium scores to risk factors measured in 1987-1989. Most traditional risk factors were associated with the coronary calcium score. For example, the multivariately adjusted odds ratio for an elevated score (> or = 100 versus < 100) was 3.5-fold greater per 10 years of age, 3.2-fold greater in men than in women, 3.1-fold greater with diabetes (statistically nonsignificant), and 1.4- to 1.7-fold greater per standard deviation greater increments of plasma cholesterol and pack-years of cigarettes smoked. Carotid artery intima-media thickness also was positively associated with coronary calcification. In contrast, a wide variety of hemostatic and inflammatory markers and serum chemistry values were unrelated to calcium scores. These findings reaffirmed the established role of traditional risk factors in the etiology of coronary artery disease, as assessed by computed tomography, but did not identify any important nontraditional risk factors.

Aged↗

PubMedDate not supplied

Treatment of chronic heart failure in a managed care setting. Baseline results from the Achieving Cardiac Excellence Project.

BACKGROUND: Effective therapy for chronic heart failure (CHF) is underutilized despite a broad consensus regarding treatment recommendations. METHODS: As a quality improvement project designed to reduce preventable hospitalizations associated with CHF, we examined use of angiotensin converting enzyme inhibitors (ACEI), angiotensin receptor blockers (ARB), and beta-adrenergic receptor blockers (BB) in a population of patients enrolled in a managed care plan. Medicare and commercial enrollees were included. Patients with CHF were identified using claims data (International Classification of Disease 9th Clinical Modification code 428) covering January 1, 1998 through December 31, 1998. Drug utilization data were obtained from the plan's pharmacy benefits database. Data were available for 1220 patients. RESULTS: The mean age (+/- SD) was 71 +/- 12 years, 53% were female, and 84% were Medicare enrollees. Prescriptions for ACEI, ARB and BB were filled by 52%, 9% and 25% of patients, respectively. Prescriptions for diuretics, digitalis preparations, and calcium channel blockers (CCB) were filled by 69%, 34%, and 32%, respectively. Therefore, almost half of patients with CHF were not receiving ACEI therapy, even though it had been proven to reduce morbidity and mortality related to CHF. Furthermore, three-quarters of patients were not receiving BB therapy, a similarly effective therapy. In contrast, CCB and digitalis have not been convincingly shown to reduce mortality in patients with CHF broadly defined. Utilization of CCB and digitalis exceeded that of BB. CONCLUSIONS: Managed care organizations should develop, test, and implement network-level strategies designed to optimize the appropriate utilization of effective drug therapies for patients with CHF.

Adrenergic beta-Antagonists↗