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Biomedical subjects

Robert Ross

Publications and source records attributed to Robert Ross.

17 recordsLinked to original sources
PubMed2003

Case management in a heterogeneous congestive heart failure population: a randomized controlled trial.

BACKGROUND: Both randomized and nonrandomized controlled studies have linked congestive heart failure (CHF) case management (CM) to decreased readmissions and improved outcomes in mostly homogeneous settings. The objective of this randomized controlled trial was to test the effect of CHF CM on the 90-day readmission rate in a more heterogeneous setting. METHODS: A total of 287 patients admitted to the hospital with the primary or secondary diagnosis of CHF, left ventricular dysfunction of less than 40%, or radiologic evidence of pulmonary edema for which they underwent diuresis were randomized. The intervention consisted of 4 major components: early discharge planning, patient and family CHF education, 12 weeks of telephone follow-up, and promotion of optimal CHF medications. RESULTS: The 90-day readmission rates were equal for the CM and usual care groups (37%). Total inpatient and outpatient median costs and readmission median cost were reduced 14% and 26%, respectively, for the intervention group. Patients in the CM group were more likely to be taking CHF medication at target doses, but dosages did not increase significantly throughout 12 weeks. Although both groups took their medications as prescribed equally well, the rest of the adherence to treatment plan was significantly better in the CM group. Subgroup analysis of patients who lived locally and saw a cardiologist showed a significant decrease in CHF readmissions for the intervention group (P =.03). CONCLUSIONS: These results suggest several limitations to the generalizability of the CHF CM-improved outcome link in a heterogeneous setting. One explanation is that the lack of coordinated system supports and varied accessibility to care in an extended, nonnetworked physician setting limits the effectiveness of the CM.

Adrenergic beta-Antagonists↗
PubMed2003

Visceral fat and liver fat are independent predictors of metabolic risk factors in men.

We examined the independent associations among abdominal adipose tissue (AT), liver fat, cardiorespiratory fitness (CRF), and lipid variables in 161 Caucasian men who had a wide variation in adiposity. We measured AT and liver fat by computed tomography and CRF by a maximal exercise test on a treadmill. Visceral AT remained a significant (P or= 0.05) correlate of any lipid variable after control for visceral AT and CRF. Furthermore, subdivision of subcutaneous AT into deep and superficial depots did not alter these observations. Visceral AT was the strongest correlate of liver fat and remained so after control for abdominal subcutaneous AT, CRF, and alcohol consumption (r = -0.34, P < 0.01). In contrast, abdominal subcutaneous AT and CRF were not significant (P > 0.10) correlates of liver fat after control for visceral AT. Visceral AT remained a significant (P < 0.01) correlate of TG, HDL-C, and TC/HDL-C independent of liver fat. However, liver fat was also a significant correlate (P <or= 0.05) of fasting glucose and TG independent of visceral AT. These observations reinforce the importance of visceral obesity in the pathogenesis of dyslipidemia in men, and they suggest that visceral AT and liver fat carry independent health risk.

Adipose Tissue↗
PubMed2003

Exercise in pregnancy and the postpartum period.

OBJECTIVE: To design Canadian guidelines advising obstetric care providers of the maternal, fetal, and neonatal implications of aerobic and strength-conditioning exercises in pregnancy. OUTCOMES: Knowledge of the impact of exercise on maternal, fetal, and neonatal morbidity, and of the maternal measures of fitness. EVIDENCE: MEDLINE search from 1966 to 2002 for English-language articles related to studies of maternal aerobic and strength conditioning in a previously sedentary population, maternal aerobic and strength conditioning in a previously active population, impact of aerobic and strength conditioning on early and late pregnancy outcomes, and impact of aerobic and strength conditioning on neonatal outcomes, as well as for review articles and meta-analyses related to exercise in pregnancy. VALUES: The evidence collected was reviewed by the Society of Obstetricians and Gynaecologists of Canada (SOGC Clinical Practice Obstetrics Committee) with representation from the Canadian Society for Exercise Physiology, and quantified using the evaluation of evidence guidelines developed by the Canadian Task Force on the Periodic Health Exam. RECOMMENDATIONS: 1. All women without contraindications should be encouraged to participate in aerobic and strength-conditioning exercises as part of a healthy lifestyle during their pregnancy. (II-1,2B) 2. Reasonable goals of aerobic conditioning in pregnancy should be to maintain a good fitness level throughout pregnancy without trying to reach peak fitness or train for an athletic competition. (II-1,2C) 3. Women should choose activities that will minimize the risk of loss of balance and fetal trauma. (III-C) 4. Women should be advised that adverse pregnancy or neonatal outcomes are not increased for exercising women. (II-1,2B) 5. Initiation of pelvic floor exercises in the immediate postpartum period may reduce the risk of future urinary incontinence. (II-1C) 6. Women should be advised that moderate exercise during lactation does not affect the quantity or composition of breast milk or impact infant growth. (I-A) VALIDATION: This guideline has been approved by the SOGC Clinical Practice Obstetrics Committee, the Executive and Council of SOGC, and the Board of Directors of the Canadian Society for Exercise Physiology. SPONSORS: This guideline has been jointly sponsored by the Society of Obstetricians and Gynaecologists of Canada and the Canadian Society for Exercise Physiology.

Adult↗
PubMed2003

Discrimination of health risk by combined body mass index and waist circumference.

OBJECTIVE: NIH Clinical Guidelines (1998) recommend the measurement of waist circumference (WC, centimeters) within body mass index (BMI, kilograms per square meter) categories as a screening tool for increased health risk. RESEARCH METHODS AND PROCEDURES: The Canada Heart Health Surveys (1986 through 1992) were used to describe the prevalence of the metabolic syndrome in Canada and to test the use of the NIH guidelines for predicting metabolic risk factors. The sample included 7981 participants ages 20 to 74 years who had complete data for WC, BMI, high-density lipoprotein-cholesterol, triglycerides, diabetic status, and systolic and diastolic blood pressures. National Cholesterol Education Program Adult Treatment Panel III risk categories were used to identify the metabolic syndrome and associated risk factors. Logistic regression was used to test the hypothesis that WC improves the prediction of the metabolic syndrome, within overweight (25 to 29.9 kg/m(2)) and obese I (30 to 34.9 kg/m(2)) BMI categories. RESULTS: The prevalence of the metabolic syndrome was 17.0% in men and 13.2% in women. The odds ratios (OR) for the prediction of the metabolic syndrome were elevated in overweight [OR, 1.85; 95% confidence interval (95%CI), 1.02 to 3.35] and obese (OR, 2.35; 95%CI, 1.25 to 4.42) women with a high WC compared with overweight and obese women with a low WC, respectively. On the other hand, WC was not predictive of the metabolic syndrome or component risk factors in men, within BMI categories. DISCUSSION: In women already at increased health risk because of an elevated BMI, the additional measurement of WC may help identify cardiovascular risk.

Abdomen↗
PubMed2003

Adipose tissue quantification by imaging methods: a proposed classification.

Recent advances in imaging techniques and understanding of differences in the molecular biology of adipose tissue has rendered classical anatomy obsolete, requiring a new classification of the topography of adipose tissue. Adipose tissue is one of the largest body compartments, yet a classification that defines specific adipose tissue depots based on their anatomic location and related functions is lacking. The absence of an accepted taxonomy poses problems for investigators studying adipose tissue topography and its functional correlates. The aim of this review was to critically examine the literature on imaging of whole body and regional adipose tissue and to create the first systematic classification of adipose tissue topography. Adipose tissue terminology was examined in over 100 original publications. Our analysis revealed inconsistencies in the use of specific definitions, especially for the compartment termed "visceral" adipose tissue. This analysis leads us to propose an updated classification of total body and regional adipose tissue, providing a well-defined basis for correlating imaging studies of specific adipose tissue depots with molecular processes.

Adipose Tissue↗
PubMed2003

Medium-chain triglycerides increase energy expenditure and decrease adiposity in overweight men.

OBJECTIVE: The objectives of this study were to compare the effects of diets rich in medium-chain triglycerides (MCTs) or long-chain triglycerides (LCTs) on body composition, energy expenditure, substrate oxidation, subjective appetite, and ad libitum energy intake in overweight men. RESEARCH METHODS AND PROCEDURES: Twenty-four healthy, overweight men with body mass indexes between 25 and 31 kg/m(2) consumed diets rich in MCT or LCT for 28 days each in a crossover randomized controlled trial. At baseline and after 4 weeks of each dietary intervention, energy expenditure was measured using indirect calorimetry, and body composition was analyzed using magnetic resonance imaging. RESULTS: Upper body adipose tissue (AT) decreased to a greater extent (p < 0.05) with functional oil (FctO) compared with olive oil (OL) consumption (-0.67 +/- 0.26 kg and -0.02 +/- 0.19 kg, respectively). There was a trend toward greater loss of whole-body subcutaneous AT volume (p = 0.087) with FctO compared with OL consumption. Average energy expenditure was 0.04 +/- 0.02 kcal/min greater (p < 0.05) on day 2 and 0.03 +/- 0.02 kcal/min (not significant) on day 28 with FctO compared with OL consumption. Similarly, average fat oxidation was greater (p = 0.052) with FctO compared with OL intake on day 2 but not day 28. DISCUSSION: Consumption of a diet rich in MCTs results in greater loss of AT compared with LCTs, perhaps due to increased energy expenditure and fat oxidation observed with MCT intake. Thus, MCTs may be considered as agents that aid in the prevention of obesity or potentially stimulate weight loss.

Adipose Tissue↗
PubMed2003

Introducing an evidence-based medicine curriculum into a family practice residency--is it effective?

PURPOSE: To investigate whether teaching an evidence-based medicine (EBM) curriculum increased the knowledge and use of EBM principles in residents' continuity clinics. METHOD: In 1999, the authors performed a needs assessment with residents and faculty of Cascades East Family Practice Residency in Oregon and constructed a ten-session EBM workshop series that was introduced into the curriculum in 2000. Resident-preceptor interactions during outpatient continuity clinic were tape-recorded prior to and six months following introduction of the curriculum. A 50-item, multiple-choice examination was administered before and after the workshop series. Residents at another FP residency at the same university served as a control group. The same assessments were applied to the experimental and control groups. The tape recordings were analyzed for interactions that contained key EBM phrases or words. RESULTS: Pre-intervention multiple-choice test results were similar (control mean 56%, experimental 53%, p >.22 NS). Post-intervention test scores for the experimental group were significantly improved (mean 72%, p <.001). There was no significant improvement in test results among members of the control group (p >.05 NS). In the recorded resident-preceptor interactions, a marked increase in the use of EBM terms indicated awareness and/or use of EBM in the experimental group. In 1,165 minutes recorded prior to the workshops, EBM terms were used in a total of ten events. In 735 minutes recorded after the workshops, EBM terms were recorded in 67 events. A reduced number of EBM terms were recorded in the control group. CONCLUSION: Administering a structured EBM curriculum increased residents' knowledge and use of EBM constructs during patient care.

Curriculum↗
PubMed2003

Abdominal adipose tissue distribution and metabolic risk.

It is now established that waist circumference remains a significant predictor of disease and metabolic risk independent of obesity measured by body mass index. These observations are reinforced by a large body of evidence implicating abdominal obesity measured by imaging modalities in the pathogenesis of numerous metabolic risk factors. However, the extent to which abdominal subcutaneous or visceral adipose tissue (AT) independently contribute to the established association between abdominal obesity and metabolic risk remains a subject of considerable research. Discrepancies in the literature may be partially explained by methodological issues, as currently there is no accepted definition for either visceral or abdominal subcutaneous AT. Accordingly, there is confusion concerning how best to measure these depots in metabolic and descriptive studies. Further, despite numerous studies linking abdominal AT depots with metabolic risk factors, the underlying mechanisms remain unclear. The primary purpose of this review is to examine the independent contribution of visceral and abdominal subcutaneous AT to the aetiology of obesity-related health risk. We begin by considering specific methodological issues with respect to the current classification of abdominal AT as measured by imaging methods. When necessary, we present original data to reinforce important concepts not suitably addressed in the literature. We conclude with a consideration of proposed mechanisms that may link abdominal adiposity and metabolic risk.

Abdomen↗
PubMed2002

Body mass index, waist circumference, and health risk: evidence in support of current National Institutes of Health guidelines.

BACKGROUND: No evidence supports the waist circumference (WC) cutoff points recommended by the National Institutes of Health to identify subjects at increased health risk within the various body mass index (BMI; calculated as weight in kilograms divided by the square of height in meters) categories. OBJECTIVE: To examine whether the prevalence of hypertension, type 2 diabetes mellitus, dyslipidemia, and the metabolic syndrome is greater in individuals with high compared with normal WC values within the same BMI category. METHODS: The subjects consisted of 14 924 adult participants of the Third National Health and Nutrition Examination Survey, which is a nationally representative cross-sectional survey. Subjects were grouped by BMI and WC in accordance with the National Institutes of Health cutoff points. Within the normal-weight (18.5-24.9), overweight (25.0-29.9), and class I obese (30.0-34.9) BMI categories, we computed odds ratios for hypertension, diabetes, dyslipidemia, and the metabolic syndrome and compared subjects in the high-risk (men, >102 cm; women, >88 cm) and normal-risk (men, <or=102 cm; women, <or=88 cm) WC categories. RESULTS: With few exceptions, within the 3 BMI categories, those with high WC values were increasingly likely to have hypertension, diabetes, dyslipidemia, and the metabolic syndrome compared with those with normal WC values. Many of these associations remained significant after adjusting for the confounding variables (age, race, poverty-income ratio, physical activity, smoking, and alcohol intake) in normal-weight, overweight, and class I obese women and overweight men. CONCLUSIONS: The National Institutes of Health cutoff points for WC help to identify those at increased health risk within the normal-weight, overweight, and class I obese BMI categories.

Adult↗
PubMed2002

Low relative skeletal muscle mass (sarcopenia) in older persons is associated with functional impairment and physical disability.

OBJECTIVES: To establish the prevalence of sarcopenia in older Americans and to test the hypothesis that sarcopenia is related to functional impairment and physical disability in older persons. DESIGN: Cross-sectional survey. SETTING: Nationally representative cross-sectional survey using data from the Third National Health and Nutrition Examination Survey (NHANES III). PARTICIPANTS: Fourteen thousand eight hundred eighteen adult NHANES III participants aged 18 and older. MEASUREMENTS: The presence of sarcopenia and the relationship between sarcopenia and functional impairment and disability were examined in 4,504 adults aged 60 and older. Skeletal muscle mass was estimated from bioimpedance analysis measurements and expressed as skeletal muscle mass index (SMI = skeletal muscle mass/body mass x 100). Subjects were considered to have a normal SMI if their SMI was greater than -one standard deviation above the sex-specific mean for young adults (aged 18-39). Class I sarcopenia was considered present in subjects whose SMI was within -one to -two standard deviations of young adult values, and class II sarcopenia was present in subjects whose SMI was below -two standard deviations of young adult values. RESULTS: The prevalence of class I and class II sarcopenia increased from the third to sixth decades but remained relatively constant thereafter. The prevalence of class I (59% vs 45%) and class II (10% vs 7%) sarcopenia was greater in the older (> or = 60 years) women than in the older men (P <.001). The likelihood of functional impairment and disability was approximately two times greater in the older men and three times greater in the older women with class II sarcopenia than in the older men and women with a normal SMI, respectively. Some of the associations between class II sarcopenia and functional impairment remained significant after adjustment for age, race, body mass index, health behaviors, and comorbidity. CONCLUSIONS: Reduced relative skeletal muscle mass in older Americans is a common occurrence that is significantly and independently associated with functional impairment and disability, particularly in older women. These observations provide strong support for the prevailing view that sarcopenia may be an important and potentially reversible cause of morbidity and mortality in older persons.

Activities of Daily Living↗
PubMed2002

Body mass index and waist circumference independently contribute to the prediction of nonabdominal, abdominal subcutaneous, and visceral fat.

BACKGROUND: It is unknown whether the ability of waist circumference (WC) to predict health risk beyond that predicted by body mass index (BMI) alone is explained in part by the ability of WC to identify those with elevated concentrations of total or abdominal fat. OBJECTIVE: We sought to determine whether BMI and WC independently contribute to the prediction of non-abdominal (total fat - abdominal fat), abdominal subcutaneous, and visceral fat. DESIGN: Fat distribution was measured by magnetic resonance imaging in 341 white men and women. Multiple regression analysis was performed to measure whether the combination of BMI and WC explained a greater variance in non-abdominal, abdominal subcutaneous, and visceral fat than did BMI or WC alone. These fat depots were also compared after a subdivision of the cohort into 3 BMI (normal, overweight, and class I obese) and 3 WC (low, intermediate, and high) categories according to the classification system used to identify associations between BMI, WC, and health risk. RESULTS: Independent of age and sex, the combination of BMI and WC explained a greater variance in non-abdominal, abdominal subcutaneous, and visceral fat than did either BMI or WC alone (P < 0.05). For non-abdominal and abdominal subcutaneous fat, BMI was the strongest correlate; thus, by adding BMI to WC, the variance accrued was greater than when WC was added to BMI. However, when WC was added to BMI, the added variance explained for visceral fat was greater than when BMI was added to WC. Furthermore, within each of the 3 BMI categories studied, an increase in the WC category was associated with an increase in visceral fat (P < 0.05). CONCLUSIONS: BMI and WC independently contribute to the prediction of non-abdominal, abdominal subcutaneous, and visceral fat in white men and women. These observations reinforce the importance of using both BMI and WC in clinical practice.

Abdomen↗
PubMed2002

A clinical-performance biopsy instrument.

A clinical-performance biopsy (CPB) instrument was introduced to enhance direct observation and timely feedback from supervising faculty during family practice resident continuity clinics.

Clinical Competence↗
PubMed2002

Application of simple anthropometry in the assessment of health risk: implications for the Canadian Physical Activity, Fitness and Lifestyle Appraisal.

Incremental improvements in our knowledge of the associations between human body composition and disease have been facilitated by advances in research technology. Magnetic resonance imaging and computerized tomography are among the technological advances that have helped unravel the mechanisms that link body composition and disease. However, because the use of these methods in large-scale studies and field settings is impractical, the potential relationships between body composition and health risk rely on the use of anthropometric tools. Indeed, the application of simple anthropometry to identify relationships between body composition and health risk in clinical practice is no less valuable than the use of advanced technologies to gain insight into the mechanistic links between body composition and disease in the laboratory. Accordingly, the purpose of this review is to summarize current knowledge regarding the ability of anthropometry to predict health risk and to act as surrogate measures of total and abdominal fat distribution. Because the ultimate objective is to make recommendations for revision to the Healthy Body Composition section of the Canadian Physical Activity, Fitness and Lifestyle Appraisal (CPAFLA) manual, we focus on those anthropometric methods specific to CPAFLA. Consistent with this objective, when necessary we present original data to reinforce important concepts not suitably addressed in the literature.

Abdomen↗
PubMed2002

Abdominal adiposity and insulin resistance in obese men.

We examined the independent relationships among various visceral and abdominal subcutaneous adipose tissue (AT) depots, glucose tolerance, and insulin sensitivity in 89 obese men. Measurements included an oral glucose tolerance test (OGTT), glucose disposal by euglycemic clamp, and abdominal and nonabdominal (e.g., peripheral) AT by magnetic resonance imaging (MRI). OGTT glucose and glucose disposal rates were related (P < 0.05) to visceral AT (r = 0.50 and -0.41, respectively). These observations remained significant (P < 0.05) after control for nonabdominal and abdominal subcutaneous AT, and maximal O(2) consumption (VO(2 max)). Abdominal subcutaneous AT was not a significant correlate (P > 0.05) of any metabolic variable after control for nonabdominal and visceral AT and VO(2 max). Division of abdominal subcutaneous AT into deep and superficial depots and visceral AT into intra- and extraperitoneal AT depots did not alter the observed relationships. Further analysis matched two groups of men for abdominal subcutaneous AT but also for low and high visceral AT. Men with high visceral AT had higher OGTT glucose values and lower glucose disposal rates compared with those with low visceral AT values (P < 0.05). A similar analysis performed on two groups of men matched for visceral AT but also for high and low abdominal subcutaneous AT revealed no statistically different values for any metabolic variable (P > 0.10). In conclusion, visceral AT alone is a strong correlate of insulin resistance independent of nonabdominal and abdominal subcutaneous AT and cardiovascular fitness. Subdivision of visceral and abdominal subcutaneous AT by MRI did not provide additional insight into the relationship between abdominal obesity and metabolic risk in obese men.

Abdomen↗
PubMed2002

Abdominal obesity, muscle composition, and insulin resistance in premenopausal women.

The independent relationships between visceral and abdominal sc adipose tissue (AT) depots, muscle composition, and insulin sensitivity were examined in 40 abdominally obese, premenopausal women. Measurements included glucose disposal by euglycemic clamp, muscle composition by computed tomography, abdominal and nonabdominal (e.g. leg) AT by magnetic resonance imaging and cardiovascular fitness. Glucose disposal rates were negatively related to visceral AT mass (r = -0.42, P < 0.01). These observations remained significant (P < 0.01) after control for nonabdominal and abdominal sc AT, muscle attenuation, and peak oxygen uptake. Total, abdominal, or leg sc AT or muscle attenuation was not significantly (P > 0.10) related to glucose disposal. Subdivision of abdominal sc AT into anterior and posterior depots did not alter the observed relationships. Further analysis matched two groups of women for abdominal sc AT but with low and high visceral AT. Women with high visceral AT had lower glucose disposal rates compared with those with low visceral AT (P < 0.05). A similar analysis performed on two groups of women matched for visceral AT but high and low abdominal sc AT revealed no statistically different values for insulin sensitivity (P > 0.10). In conclusion, visceral AT alone is a strong correlate of insulin resistance independent of nonabdominal, abdominal sc AT, muscle composition, and cardiovascular fitness. Subdivision of abdominal sc AT did not provide additional insight into the relationship between abdominal obesity and metabolic risk.

Abdomen↗
PubMed2002

Effects of an energy-restrictive diet with or without exercise on abdominal fat, intermuscular fat, and metabolic risk factors in obese women.

OBJECTIVE: The primary objective was to examine whether the combination of diet and aerobic exercise (DA) or diet and resistance exercise (DR) is associated with greater improvements in metabolic risk factors by comparison to diet only (DO) in obese women. A second objective considered whether reductions in metabolic risk factors are related to concurrent changes in abdominal and/or intermuscular fat distribution. RESEARCH DESIGN AND METHODS: A total of 38 premenopausal obese women were randomly assigned to one of three 16-week treatments: DO (n=13), DA (n=11), or DR (n=14). Plasma glucose, insulin, and lipid levels were measured in a fasting state and after a 75-g oral glucose challenge (oral glucose tolerance test [OGTT]). Total, abdominal subcutaneous, visceral, and intermuscular fat were measured by magnetic resonance imaging. RESULTS: Significant reductions (P < 0.02) in body weight (approximately 10 kg or 10%) and in total, abdominal subcutaneous, visceral, and intermuscular fat were observed within each group. Fasting and OGTT insulin, total cholesterol, LDL cholesterol, and apolipoprotein B also decreased within each group (P < or = 0.02). The changes in the body fat and metabolic variables were not different across treatment (P > 0.05). Visceral fat alone was related to the metabolic risk factors both before and after the treatment. CONCLUSIONS: Weight loss was associated with reductions in metabolic risk factors in obese women. The improvement in the metabolic profile was not enhanced by the addition of aerobic or resistance exercise. The findings reinforce the importance of diminished visceral fat in the treatment of insulin resistance.

Abdomen↗