Search PubMed⌕ Search

Biomedical subjects

C B Eaton

Publications and source records attributed to C B Eaton.

At least 19 recordsLinked to original sources
PubMed2006

Novel fast semi-automated software to segment cartilage for knee MR acquisitions.

OBJECTIVE: Validation of a new fast software technique to segment the cartilage on knee magnetic resonance (MR) acquisitions. Large studies of knee osteoarthritis (OA) will require fast and reproducible methods to quantify cartilage changes for knee MR data. In this report we document and measure the reproducibility and reader time of a software-based technique to quantify the volume and thickness of articular cartilage on knee MR images. METHODS: The software was tested on a set of duplicate sagittal three-dimensional (3D) dual echo steady state (DESS) acquisitions from 15 (8 OA, 7 normal) subjects. The repositioning, inter-reader, and intra-reader reproducibility of the cartilage volume (VC) and thickness (ThC) were measured independently as well as the reader time for each cartilage plate. The root-mean square coefficient of variation (RMSCoV) was used as metric to quantify the reproducibility of VC and mean ThC. RESULTS: The repositioning RMSCoV was as follows: VC=2.0% and ThC=1.2% (femur), VC=2.9% and ThC=1.6% (medial tibial plateau), VC=5.5% and ThC=2.4% (lateral tibial plateau), and VC=4.6% and ThC=2.3% (patella). RMSCoV values were higher for the inter-reader reproducibility (VC: 2.5-8.6%) (ThC: 1.9-5.2%) and lower for the intra-reader reproducibility (VC: 1.6-2.5%) (ThC: 1.2-1.9%). The method required an average of 75.4min per knee. CONCLUSIONS: We have documented a fast reproducible semi-automated software method to segment articular cartilage on knee MR acquisitions.

Cartilage, Articular↗
PubMed2006

A retrospective study of the relationship between biomarkers of atherosclerosis and erectile dysfunction in 988 men.

Erectile dysfunction (ED) is associated with clinical atherosclerosis and several atherosclerotic risk factors including smoking, hypertension, dyslipidemia, diabetes mellitus, obesity and sedentary lifestyle. Clinical atherosclerosis is also associated with these same risk factors and with biomarkers of inflammation, thrombosis, endothelial cell activation. We evaluated the cross-sectional association between the degree of ED and levels of atherosclerotic biomarkers. A subcohort of 988 US male health professionals between the ages 46 and 81 years as part of an ongoing epidemiologic study had atherosclerotic biomarkers measured from blood collected in 1994-1995. These same men had in 2000, been retrospectively asked about erectile function in 1995 and in 2000. Biennial questionnaires since 1986 assessed medical conditions, medications, smoking, physical activity, body mass index, alcohol intake. The retrospective assessment of erectile function in 2000 for 1995 in these 988 men ranged from very good - 28.2%, good - 25.1%, fair - 19.2%, poor - 13.6%, to very poor - 13.9%. Men with poor to very poor erectile function compared to men with good and very good erectile function had 2.9 the odds of having elevated Factor VII levels (P=0.03), 1.9 times the odds of having elevated vascular cell adhesion molecule (P=0.13) and 2.0 times the odds of having elevated intracellular adhesion molecule (P=0.06) and 2.1 times the odds of having elevated total cholesterol/high-density lipoprotein ratio (P=0.02) comparing the top to bottom quintiles for each atherosclerotic biomarker after multivariate adjustment. Lipoprotein(a), homocysteine, interleukin-6 and tumor necrosis factor receptor, C-reactive protein and fibrinogen were not associated with the degree of erectile function after adjustment. We conclude that selected biomarkers for endothelial function, thrombosis and dyslipidemia but not inflammation are associated with the degree of ED in this cross-sectional analysis. Future studies evaluating the prospective association of ED, endothelial function and cardiovascular disease appear warranted.

Aged↗
PubMed2005

Double echo steady state magnetic resonance imaging of knee articular cartilage at 3 Tesla: a pilot study for the Osteoarthritis Initiative.

BACKGROUND: Quantitative magnetic resonance imaging (qMRI) may provide valuable measures of cartilage morphology in osteoarthritis (OA) but has been confined to sequences with relatively long acquisition times at 1.5 Tesla (T). OBJECTIVE: To test the accuracy and precision of knee cartilage qMRI with a fast double echo, steady state (DESS) sequence with water excitation (we) at 3 T. METHODS: As a pilot study for the Osteoarthritis Initiative, test-retest MR images were acquired in the knees of 19 participants with no OA to moderate degrees of clinical OA. Two double oblique coronal fast low angle shot (FLASHwe) sequences (1.5 mm slice thickness) were acquired at 3 T, and two sagittal DESSwe sequences (0.7 mm slice thickness). Double oblique coronal multiplanar reformats (MPR) were performed (1.5 mm slice thickness) from the sagittal DESSwe. Knee joint cartilage plates were quantified unpaired in random order with blinding to subject identification. RESULTS: In the femorotibial joint, precision errors (root mean square coefficient of variation in % for unpaired analysis) for cartilage volume and thickness were 3.0-6.4% with coronal FLASHwe, 2.4-6.2% with coronal MPR DESSwe, and 2.3-8.2% with sagittal DESSwe. Correlation coefficients between DESSwe and FLASHwe ranged from r = 0.88 to 1.0. In the femoropatellar joint, precision errors (sagittal DESSwe) were 3.4-8.5%. CONCLUSIONS: DESSwe permits accurate and precise analysis of cartilage morphology in the femorotibial joint at 3 T. Further studies are needed to examine the accuracy of DESSwe in the femoropatellar joint and its ability to characterise sensitivity to longitudinal changes in cartilage morphology.

Adult↗
PubMed2001

Effect of antiplatelet and anticoagulant agents on risk of hospitalization for bleeding among a population of elderly nursing home stroke survivors.

BACKGROUND AND PURPOSE: Anticoagulants and antiplatelet agents are underutilized in the nursing home setting, perhaps because trials demonstrating treatment efficacy excluded people resembling those with long-term care needs. We sought to quantify the effect of antiplatelet and anticoagulant agents on risk of hospitalization for bleeding among an elderly nursing home population. METHODS: We used a case-control design and identified first hospitalizations for bleeds using Medicare claims data from 1992 to 1997 as potential cases. Cases had at least one minimum data set (MDS) assessment within the 6 months before that hospitalization and a diagnosis of stroke. We identified up to 5 controls residing in the same facility during the same year and quarter as the case with a diagnosis of stroke. Our sample consisted of 3433 cases and 13 506 controls. Using the MDS, we identified standing orders for aspirin, dipyridamole, ticlopidine, or warfarin and used conditional logistic regression modeling to estimate the effect of these agents on risk of hospitalization for a bleed. RESULTS: After adjustment, use of warfarin (odds ratio [OR], 1.26; 95% CI, 1.11 to 1.43) and combination therapy (OR, 1.34; 95% CI, 0.99 to 1.82) were associated with an increased risk of hospitalization for a bleed compared with nonusers. The odds of aspirin use was greater among cases than controls (OR, 1.07; 95% CI, 0.96 to 1.18) after adjustment. CONCLUSIONS: Although present, the risk associated with use of these agents is small. The numbers needed to treat to harm 1 resident with aspirin and warfarin were 467 and 126, respectively.

Age Distribution↗
PubMed1999

The effect of physician office visits on CHD risk factor modification as part of a worksite cholesterol screening program.

BACKGROUND: Elevated serum cholesterol is a major risk factor for CHD. Primary prevention through behavioral modification has been designated first-line treatment for patients with elevated cholesterol. In this study, we assessed the impact of a physician office visit after a worksite cholesterol screening on self-reported changes in diet, weight loss, exercise, and smoking. We hypothesized that those individuals who had a physician office visit regarding cholesterol would make more changes in CHD risk factors than those who did not have such a visit. METHODS: A cohort of 4,928 participants from 33 work-sites in Massachusetts and Rhode Island had baseline CHD risk factors evaluated at a cholesterol screening and 4,473 were available at follow-up 6 months later by telephone interview. A total of 1,957 had elevated cholesterol levels (>/=200 mg;/dl) and were instructed to visit their physician, in addition to receiving educational materials related to CHD risk factor modification. RESULTS: Most individuals with elevated cholesterol levels had other prevalent self-reported CHD risk factors at baseline: 58% consumed high-fat diets (>30% fat), 43% were overweight, 60% had a sedentary lifestyle (sweat-related physical activity <3 x per week), and 22% were cigarette smokers. After 6 months of follow-up, 74% of participants with high-fat diets reported eating a lower fat diet, 71% of overweight participants reported weight loss, 53% of sedentary participants attempted to increase physical activity, and 38% of smokers decreased or quit cigarette smoking. Thirty-five percent of participants completed the referral for a physician office visit to discuss their elevated cholesterol determined at the baseline worksite screening. However, these individuals showed only a modest change (which was not statistically significant) in self-reported CHD risk factors compared with those who did not have follow-up physician visits after adjusting for age, sex, race, education, occupation, medical insurance, time since last doctor visit, diabetes, and hypertension. Objective measurements of serum cholesterol, body mass index, and dietary score were likewise modestly improved and not statistically significant. CONCLUSIONS: In 6 months of follow-up, high absolute levels of CHD risk factor modification were observed after a worksite cholesterol screening. A physician office visit added only a modest but not statistically significant benefit for further CHD risk factor modification. These findings indicate that the follow-up cholesterol-related physician visit had little added clinical benefit over the screening intervention alone.

Adult↗
PubMed1999

Effects of a community-based intervention on physical activity: the Pawtucket Heart Health Program.

OBJECTIVES: The effect of a community-based physical activity program in Pawtucket, RI, was evaluated relative to one in a comparison community. METHODS: Cross-sectional surveys of 7529 residents of Pawtucket, RI, and 7732 residents of the comparison city were conducted at 2-year intervals during 7 years of intervention. RESULTS: There were no differences in self-reported knowledge of the benefits of physical activity, attempts to increase exercise, or prevalence of physical inactivity between Pawtucket and the comparison community. CONCLUSIONS: Future community-based physical activity interventions should attempt to involve a wider range of individuals.

Adult↗
PubMed1998

A systematic review of physical activity promotion in primary care office settings.

OBJECTIVE: To assess the efficacy of physical activity promotion in primary care office settings. DESIGN: Systematic review of clinical trials in which the efficacy of physical activity promotion was investigated in a primary care office setting with at least one month of follow up. SUBJECTS: A total of 13,981 adults, aged 17-85+, were included from 203 practices in eight trials assessing physical activity promotion in primary care office settings. MAIN OUTCOME MEASURES: Odds ratios and 95% confidence intervals were calculated comparing the number of participants who increased their physical activity or were active at follow up in the intervention group with a control group for each study. RESULTS: Five of eight trials where positive with statistically significant results (range 0.91-6.56), but significant biases or limited clinical relevance of the outcomes were found in all trials. Short term trials of less than one year (four of four were positive), single-risk-factor trials (three of three were positive), randomised clinical trials (two of three were positive), and those assessing moderate levels of physical activity (three of four were positive) were most likely to find benefit. Only one of four trials lasting longer than a year were positive. CONCLUSION: There is limited evidence from well designed trials that office based physical activity promotion in primary care settings is efficacious in promoting changes in physical activity that could conceivably have lasting clinical benefits.

Adolescent↗
PubMed1995

Self-reported physical activity predicts long-term coronary heart disease and all-cause mortalities. Twenty-one-year follow-up of the Israeli Ischemic Heart Disease Study.

OBJECTIVE: To determine whether self-reported physical activity predicts a decreased rate of coronary heart disease (CHD) and all-cause mortalities in middle-aged men when rates are adjusted for known confounders. DESIGN: Cohort Analytic Study of Israeli government employees in 1963. SUBJECTS: Eight thousand four hundred sixty-three Israeli male government employees, aged 40 years or older, representing six areas of birth, excluding those with known cardiovascular disease in either 1963 or 1965, from an original cohort of 10,059. MAIN OUTCOME MEASURE: Comparison of rates of death due to CHD and all causes, determined from death certificates in 21 years of follow-up, for subjects with different baseline levels of self-reported leisure-time and work-related physical activities measured in 1965. RESULTS: Self-reported leisure-time but not work-related physical activity was inversely related to both CHD (adjusted relative risk, 0.79; 95% confidence interval, 0.66 to 0.95) and all-cause mortalities (adjusted relative risk, 0.91; 95% confidence interval, 0.83 to 0.99). Most of the apparent benefit accrued was from light physical activity on less than a daily basis. These inverse relationships persisted after adjustment for age, systolic blood pressure, cigarette smoking, total and high-density lipoprotein cholesterol levels, body mass index, psychosocial factors, and other potential confounders. CONCLUSION: Baseline levels of self-reported leisure-time physical activity predicted a decreased rate of CHD and all-cause mortalities in employed middle-aged Israeli men followed up prospectively for 21 years.

Adult↗
PubMed1995

Exercise prescription.

Exercise can increase longevity and improve overall health and quality of life. Since a large proportion of Americans have a sedentary lifestyle, exercise counseling should be a part of routine health maintenance. Physicians need to provide patients with information about the specific benefits of exercise and motivate them to increase their physical activity. Physicians should encourage all adults, including those who elect not to participate in a formal exercise program, to accumulate 30 minutes or more of moderate-intensity physical activity on most days of the week. Before beginning an exercise program, selected higher risk patients may need to be evaluated with a physical examination and a treadmill test. Many patients benefit from a preexercise determination of fitness and specific instructions for monitoring their heart rate to maintain exercise within appropriate target ranges. A formal exercise prescription should include specific advice about the type, frequency, intensity, duration and progression of physical activity. Once an exercise regimen has begun, injury prevention and adherence to the program become important.

Algorithms↗
PubMed1995

Physical activity, physical fitness, and coronary heart disease risk factors.

The relationships between physical activity, physical fitness, and coronary heart disease risk factors measured in a large community sample were evaluated. Self-reported physical activity using a single question, maximal oxygen consumption estimates derived from the Pawtucket Heart Health Step Test, blood pressure, nonfasting lipids, and body mass index were cross-sectionally evaluated in 381 men and 556 women. The correlation of estimated maximal oxygen consumption and self-reported physical activity was modest but statistically significant (r = 0.13 in men and r = 0.19 in women). Blood pressure, body mass index, and HDL cholesterol were correlated with physical fitness (r = 0.24-0.65) and correlated to self-reported physical activity (r = 0.09-0.14). Evaluation of coronary heart disease risk factors using both physical activity and physical fitness revealed a complex relationship that generally showed a stronger relationship with measures of physical fitness than with physical activity. This study suggests that simultaneous measurement of physical activity and physical fitness may be useful in epidemiologic studies of habitual physical activity and chronic disease.

Adolescent↗
PubMed1995

Sedentary lifestyle and risk of coronary heart disease in women.

Relatively few studies have assessed the prospective relationship of sedentary lifestyle and coronary heart disease (CHD) in women. We performed a nested case-control study, identifying 50 cases of acute CHD in women and 150 age-matched controls. Risk factors including sedentary lifestyle, cigarette smoking, hypertension, diabetes mellitus, total, and HDL cholesterol levels had been previously determined in this cohort using household survey techniques. The odds ratio (OR) of CHD in sedentary women was 2.1 (95% CI 1.0-4.3, P = 0.046). The odds ratio was similar (OR = 2.3, 95% CI 1.0-5.7, P = 0.051) after adjusting for potential confounders of hypertension, cigarette smoking, low HDL cholesterol, diabetes mellitus, and being U.S. born. This study suggests that sedentary lifestyle may be an independent risk factor for CHD in women, but its results are open to several contradictory interpretations. Further studies to investigate the prospective relationship of sedentary lifestyle and the risk of CHD in women are needed.

Case-Control Studies↗
PubMed1994

Cost-benefit analysis of walking to prevent coronary heart disease.

OBJECTIVE: To quantify the cost-benefit relationship of walking to prevent coronary heart disease. DESIGN: Cost-benefit analysis. PARTICIPANTS: Hypothetical cohorts of sedentary men and women aged 35 to 74 years. MAIN OUTCOME MEASURES: Decision-analysis simulation was used to evaluate the cost-benefit relationship of walking, varying level of benefit from exercise, frequency of exercise to achieve benefit, participation rates, and costs of exercise and injury. RESULTS: At a relative risk of 1.9 for heart disease associated with sedentary behavior, $5.6 billion would be saved annually if 10% of adults began a regular walking program. A $4.3 billion savings is predicted if the entire sedentary population began walking regularly and the cost of the time an individual spends exercising is accounted for in those who dislike exercising. According to our baseline assumptions, walking is economically beneficial for men aged 35 to 64 years and for women aged 55 to 64 years. The threshold of relative risk at which economic benefit is found for walking in this population overall is estimated at 1.7, and under a volunteer model, most adults would benefit even at a relative risk of 1.15. CONCLUSIONS: There are significant sex and age differences in the economic benefits of walking to prevent heart disease. The value assigned to the time an individual spends exercising has a significant impact on the results. Overall, a substantial savings is predicted from encouraging sedentary individuals to participate in a regular walking program.

Adult↗
PubMed1994

Dietary differences in smokers and nonsmokers from two southeastern New England communities.

OBJECTIVE: Previous studies based on 24-hour dietary recall data have shown that smokers tend to consume less healthful diets than nonsmokers. We tested this hypothesis using data from food frequency questionnaires (FFQs) in a group of men and women. DESIGN: Characteristics of smokers and nonsmokers were compared using data collected from a cross-sectional household health survey. SUBJECTS: Adults aged 18 through 64 years from two communities in southeastern New England were randomly selected for the study and interviewed in their homes by trained personnel. The interview included questions on demographic and behavioral characteristics. Height, weight, blood pressure, and serum lipids were measured using standard protocols. The Willett FFQ was completed by 1,608 of 2,531 eligible respondents who made up our study sample. STATISTICAL ANALYSES PERFORMED: Respondents were categorized as current cigarette smokers or nonsmokers. Demographic, behavioral, physiologic, and dietary characteristics were compared between smokers and nonsmokers by analysis of covariance with age as the covariate. RESULTS: Eligible respondents who did not complete the FFQ differed from respondents with respect to age, gender, smoking prevalence, and several other demographic characteristics. Smokers consumed more energy, fat, alcohol, and caffeine than nonsmokers. Smoking status was inversely associated with intake of vitamins A and C, dietary fiber, folate, and iron among women, whereas differences were smaller and not significant among men. Women who smoked consumed fewer servings of fruits and vegetables than nonsmokers, but this trend was not noted in men. The association between diet and smoking was only slightly diminished by multivariate adjustment for age, income, regular exercise, marital status, and working status but most clinically relevant associations remained. The interaction between gender and smoking was not statistically significant for most dietary variables. CONCLUSIONS: These results suggest that health promotion messages targeted to smokers should include dietary instructions, especially for women.

Adult↗
PubMed1994

High dose ascorbate supplementation fails to affect plasma homocyst(e)ine levels in patients with coronary heart disease.

Pharmacologic doses of folate, in the absence of clinical folate deficiency, can reduce plasma levels of the putatively atherothrombotic amino acid, homocysteine (H(e)). Data suggesting that H(e) may accumulate in experimental scurvy prompted us to explore the efficacy of high dose ascorbate supplementation as a H(e)-lowering treatment, in the absence of clinical ascorbate deficiency. A randomized, placebo-controlled trial of 12 weeks of high dose (4.5 g/day) ascorbate supplementation was completed by 44 patients with established coronary heart disease. No significant change in mean fasting total plasma H(e) levels was demonstrable despite a marked increase in mean fasting plasma ascorbate levels amongst those patients randomized to active treatment. Ascorbate supplementation to prevent the development of fasting hyperhomocysteinemia may only be relevant at scorbutic levels of plasma ascorbate.

Ascorbic Acid↗