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Biomedical subjects

V Burke

Publications and source records attributed to V Burke.

At least 91 records · Page 5Linked to original sources
PubMed1996

Strategies for prevention of adult hypertension and cardiovascular risk behaviour in childhood. An Australian perspective.

This paper addresses approaches to evaluating the importance of different childhood behaviours on subsequent risk of high blood pressure and related cardiovascular risk factors and outlines results of a randomised controlled trial of nutrition and exercise interventions in schoolchildren. Clustering of cardiovascular risk factors was studied in relation to diet, blood pressure, fitness, fatness and blood cholesterol in a representative sample of 555 Perth schoolchildren aged 15 years. Twenty-one percent of males and females had high risk profiles associated with dietary excesses, particularly in fat, cholesterol and sodium intake, and deficiencies of minerals, vitamins and dietary fibre. Socio-economic status was inversely associated with cardiovascular risk and undernutrition in girls. Thus 21% of the school children shared unhealthy lifestyles putting them at substantial risk of subsequent cardiovascular disease. A randomised controlled trial designed to reduce cardiovascular risk was conducted in 1147 children 10-12 years old, assigned to one of six groups for a year. The groups were fitness, fitness and school nutrition, school nutrition, school and home nutrition, home nutrition or controls. On cluster analysis 30% of the children were at higher risk at baseline in terms of blood pressure, blood cholesterol levels, fitness and body fat. With the fitness programmes fitness increased in both high and low risk girls but only in high risk cluster boys. Systolic pressure fell more in the high risk boys in the fitness group than in low risk boys, while diastolic pressure fell in girls regardless of initial risk. Triceps skinfold thickness fell more in higher than lower risk girls in the school and home nutrition group, and more in high risk boys in the home nutrition group. Higher risk girls showed a greater reduction in fat intake and increase in dietary fibre with home nutrition programmes. We concluded that higher risk children do show greater responses to lifestyle intervention programmes in general, with the greatest effects seen with home nutrition or fitness programmes. The results indicate the need for different approaches to prevention of hypertension and cardiovascular risk in higher and lower risk children and for boys and girls.

Adolescent↗
PubMed1995

Angiotensin-converting enzyme and apolipoprotein E genotypes and restenosis after coronary angioplasty.

BACKGROUND: An insertion/deletion (I/D) polymorphism in the gene for angiotensin-converting enzyme (ACE) has been associated with myocardial infarction and other cardiac pathology. There is evidence for a role of the renin-angiotensin system in cell growth and in the repair of damaged arterial walls, so the ACE gene was postulated to be a candidate gene affecting the important clinical problem of restenosis after percutaneous transluminal balloon coronary angioplasty (PTCA). Because restenosis is influenced by the apolipoprotein E (apoE) genotype, the possibility of a relation between ACE and apoE genotypes and restenosis was also sought. METHODS AND RESULTS: Subjects (< 70 years of age) were prospectively followed and had coronary angiography 6 months after PTCA to determine the presence or absence of restenosis. Those who had angiography earlier and did not have restenosis (> or = 50% loss of gain at PTCA plus > or = 50% luminal diameter stenosis) also had angiography at 6 months. The whole group (n = 207) had a higher DD genotype frequency than did 136 population control subjects (38% versus 26%, P < .02); in PTCA patients, the frequency was the same in those with and without prior myocardial infarction. The distribution of ACE genotypes was not different in the 88 patients with and 119 patients without restenosis, while the epsilon 4/4 genotype was more frequent in those with restenosis (8 of 88 versus 3 of 118, P < .05). There was no effect of the ACE genotype in noncarriers of the epsilon 4 allele, but there was a significant effect in epsilon 4 carriers (P < .005). The combined D and epsilon 4 carrier state showed a 16-fold increase in the odds ratio for restenosis (P < .02). Multiple linear regression examining the loss of lumen as a continuous variable showed significant independent effects of the ACE and apoE genotypes. CONCLUSIONS: Overall, the ACE genotype had no clear influence on restenosis, but there was an interaction between ACE and apoE genotypes. The combined carrier state for the D and apoE epsilon 4 alleles substantially increased restenosis. For loss of lumen as a continuous variable, there were significant effects of both ACE and apoE genotypes. While the observations may not affect current management, they no doubt have implications in pathophysiology.

Angioplasty, Balloon, Coronary↗
PubMed1995

A controlled evaluation of a fitness and nutrition intervention program on cardiovascular health in 10- to 12-year-old children.

BACKGROUND: Programs to improve cardiovascular health in schoolchildren need careful scientific evaluation. METHOD: In a randomized controlled trial of nutrition and fitness programs over a period of about 9 months, 1,147 10- to 12-year-olds from 30 schools were allocated to one of five health programs: fitness, fitness + school nutrition, school-based nutrition, school + home nutrition, home-based nutrition, or a control group. Nutrient intake, fitness, anthropometry, blood pressure, and blood cholesterol were measured before and after intervention. RESULTS: Fitness increased and diastolic blood pressure and triceps skinfolds decreased significantly for girls in the fitness groups. Baseline consumption of sugar, fat, and fiber was outside national guidelines; blood cholesterol exceeded recommendations in one-third of children. In girls, fat intake decreased significantly in the two home nutrition groups and fiber intake increased in the school + home nutrition and fitness groups. Boys in the fitness, fitness + school nutrition, and school + home nutrition group reduced sugar intake. Change in sugar intake correlated negatively with change in fat intake in both boys and girls. CONCLUSIONS: Teacher-implemented health packages are feasible with minimal training but programs should differ between boys and girls. Fitness programs were more successful than nutrition education particularly in girls. Clearer nutrition messages should prevent reciprocal changes in sugar and fat. For girls, the 3 mm Hg reduction of diastolic blood pressure, less obesity, and increased fitness could translate into a substantial reduction in cardiovascular risk in adult life.

Blood Pressure↗
PubMed1995

Vegetarian diet components, protein and blood pressure: which nutrients are important?

1. Evidence that vegetarian dietary patterns lower blood pressure (BP) comes from both population studies and randomized controlled trials in normotensive and hypertensive subjects. 2. The effect has been shown most clearly in those who keep to a strict lacto-ovo vegetarian diet characterized by a relatively low intake of saturated fat, a high polyunsaturated/saturated fat ratio, and a high intake of fruit, vegetables and other fibre containing products. Randomized controlled dietary trials suggest the effects are independent of dietary sodium, additive to that of calorie restriction, and not due to the absence of meat protein per se. Indeed, recent population studies suggest an inverse relationship between dietary protein and BP. 4. Dietary fats, fibre, potassium, magnesium and calcium do not independently seem to account for the effects. A possible role for complex carbohydrate in conjunction with the other dietary factors has yet to be fully explored.

Blood Pressure↗
PubMed1995

Assessment of nutrition and physical activity education programmes in children.

1. Studies in children relating blood lipids to the extent of atherosclerosis at post-mortem suggest a link between risk factors for cardiovascular disease in childhood and adult life. Tracking of blood pressure (BP) and cholesterol from childhood also supports this association. However, prospective studies have not yet established the outcome in children with increased levels of risk factors. 2. In a controlled trial in Perth, Western Australia, involving over 1000 10-12 year old children, fitness was improved by physical activity programmes which were associated with a greater fall in diastolic BP and triceps skinfolds in girls compared with controls. Sugar intake decreased in boys and fat intake fell in girls, mainly affecting participants in home nutrition programmes. 3. In higher risk children, identified by cluster analysis, major benefits were associated with the fitness and home nutrition programmes. Physical activity combined with involvement of the family in nutrition education is likely to be the most successful approach to modifying lifestyle in children, including those with higher levels of risk. 4. Undernutrition by too rigid restriction of fat intake must be avoided in young children who need calorie-dense foods. Undernutrition, in itself, may predispose to cardiovascular disease in later life. Programmes should aim to establish a prudent diet appropriate to the age of the child combined with physical activity. As regular activity and a healthy diet in adult life will reduce risks of cardiovascular disease it is likely that childhood education will establish lifestyle habits of potential long-term benefit.

Adolescent↗
PubMed1995

Increased blood pressure and changes in membrane lipids associated with chronic ethanol treatment of rats.

1. Changes in membrane fluidity have been proposed to contribute to the pathogenesis of ethanol-induced hypertension possibly through changes in membrane lipid patterns, but reports are inconsistent. 2. In a controlled trial we documented ethanol-induced changes in blood pressure and composition of membrane lipids in ethanol-fed rats. 3. Systolic blood pressure increased significantly in the ethanol-treated rats (9.3 mmHg, s.e.m. 2.9) compared with the control group (-1.3 mmHg, s.e.m. 2.6). Mean cholesterol content in red cell membranes did not differ significantly between ethanol-fed and control rats. Phospholipids of aorta, red cells and kidney showed a significant decrease in the polyunsaturated to saturated fatty acid ratio, while membrane phospholipids from the heart showed a significant increase in the polyunsaturated to saturated fatty acid ratio with ethanol treatment. 4. In univariate regression blood pressure was significantly negatively related to levels of arachidonic acid in the kidney (P = 0.0013) and to linoleic acid in the aorta (P = 0.0341) and red cells (P = 0.0289). Blood pressure was not significantly related to fatty acids in the heart nor to membrane cholesterol or phospholipids. 5. Differences in fatty acid composition of phospholipids between controls and ethanol-fed rats are consistent with altered membrane fluidity. Altered membrane function is a potential mechanism involved in ethanol-induced hypertension.

Animals↗
PubMed1995

Relationships between nutrient intake and progression/regression of coronary atherosclerosis as assessed by serial quantitative angiography.

To elucidate the direction and magnitude of effects of nutrition on coronary artery disease (CAD), the relation between nutrient intake and angiographic changes were examined in the course of a controlled dietary trial. Ninety men with symptomatic CAD and serum cholesterol greater than 232 mg/dL were entered into a randomized controlled trial of a lipid-lowering diet, or of diet plus cholestyramine, compared with usual cardiac care. Of those in the first and second groups, 50 patients completed the trial and are the subject of this report. Quantitative coronary angiography was performed at baseline and at 39 months. From repeated dietary assessment during the trial, mean nutrient intakes were computed, and their relationships with change of coronary artery narrowing were analyzed. Progression of coronary disease was directly, strongly and independently associated with intake of saturated fatty acids of chain length 14-18. This was not fully explained by the effects of saturated fat in raising serum cholesterol; after adjustment for low density lipoprotein cholesterol level, stearic acid (C18:0) intake remained independently predictive of progression. No 'protective' effect of linoleic, linolenic or eicosapentaenoic acid was demonstrable. Intake of trans fatty acids was directly related to progression. Together with the favourable treatment effects on angiographic appearance and clinical end-points, these findings provide further support for a causal role of saturated fats in CAD; restriction of foods containing such fats should be emphasized as part of regimens aimed to reduce progression of coronary atherosclerosis.

Adult↗
PubMed1995

Clustering of cardiovascular risk factors in Australian adolescents: association with dietary excesses and deficiencies.

BACKGROUND: Effective cardiovascular disease prevention requires strategies aimed at those children and adolescents most at risk. This study was designed to identify adolescents with clustering of higher levels of cardiovascular risk factors related to diet, blood pressure, fitness, fatness and blood cholesterol. METHODS: A representative sample of 555 schoolchildren aged 15 years from the Perth, Australia metropolitan area, was included in a cross-sectional survey analysing relationships between nutrient intake, fitness, physical activity, percentage of body fat, blood pressure and heart rate. RESULTS: Cluster analysis identified 21.1% of boys and 20.7% of girls with significantly worse risk profiles. Higher cardiovascular risk was associated with both dietary excesses, particularly in fat, cholesterol and sodium intake, and deficiencies of a number of minerals, vitamins and dietary fibre. Socioeconomic status was inversely associated with cardiovascular risk and undernutrition in girls. CONCLUSIONS: The analysis has identified a subgroup of about 21% of 15-year-old schoolchildren who share features of a range of unhealthy lifestyle variables, putting them at substantial risk of cardiovascular disease and other ill health in later life.

Adolescent↗
PubMed1994

Effects of varying dietary fat, fish, and fish oils on blood lipids in a randomized controlled trial in men at risk of heart disease.

This study aimed to determine the effects of incorporating fish with 40%- or 30%-fat diets and the differences in response to fish or fish oil omega 3 fats. Men with high-normal blood pressure and elevated serum cholesterol were randomly allocated to one of seven diets for 12 wk. Fish or fish oil with a 40%-fat diet increased total cholesterol, HDL cholesterol, HDL2 cholesterol, and LDL cholesterol, and reduced triglycerides. The 30%-fat diet alone reduced cholesterol, LDL cholesterol, and HDL cholesterol, with triglycerides unchanged. Fish with the 30%-fat diet reduced cholesterol, LDL cholesterol, and triglycerides and increased HDL2 cholesterol. This study has shown that plasma lipids are affected similarly by fish or fish oil in men consuming a 40%-fat diet. Adverse effects of omega 3 fats on total and LDL cholesterol are reversed by a 30%-fat diet, whereas one daily fish meal substantially lowers triglycerides and reverses the fall in HDL cholesterol that is usual with a low-fat diet.

Adult↗
PubMed1993

Diffuse and enteroaggregative patterns of adherence of enteric Escherichia coli isolated from aboriginal children from the Kimberley region of Western Australia.

Escherichia coli from 138 fecal samples from aboriginal children, in whom no other enteric pathogen was isolated (including enterovirulent E. coli), were examined for HEp-2 cell adhesion. Twenty-five (36.8%) of 68 children with diarrhea and 32 (45.7%) of 70 without diarrhea had diffusely adherent isolates, which were thus not associated with diarrhea (P > .25). However, after age stratification, children > or = 18 months showed a significant association of diffusely adherent E. coli with diarrhea (P < or = .05). Enteroaggregative E. coli were isolated from 12 children with diarrhea (17.6%) and 15 without diarrhea (21.4%); thus, there was no association with diarrhea (P > or = .5). Sixteen children with diarrhea (23.5%) and 6 without diarrhea (8.6%) carried isolates that caused detachment of the HEp-2 cell monolayer from the glass coverslip when examined in the adhesion assay and were significantly associated with diarrhea (P < or = .05). These isolates, termed cell-detaching E. coli, were different from all recognized classes of enterovirulent E. coli.

Age Factors↗
PubMed1993

Ambulatory blood pressure and heart rate responses to vegetarian meals.

OBJECTIVES: To determine the effects of a vegetarian diet on daytime ambulatory (Accutracker) blood pressures and heart rates, and to relate these to the estimated peak in plasma glucose to determine whether low-glycaemic-index diets reduce sympathetic activity in response to differences in postprandial glucose and insulin. DESIGN: The subjects were matched for age and body mass index and randomly assigned to one of two parallel diet groups. SETTING: Clinical. PARTICIPANTS: Twenty-one normotensive non-vegetarian male hospital workers volunteered for the study and 20 completed it. INTERVENTION: After 2 weeks of baseline measurement the subjects followed an omnivorous or a lacto-ovovegetarian diet for 6 weeks. MAIN OUTCOME MEASURES: Daytime ambulatory blood pressures and heart rate, and postbreakfast catecholamines, insulin and glucose. RESULTS: Ambulatory systolic blood pressure and heart rates were lower in the vegetarian group during the working day. The preprandial rise in diastolic pressure was attenuated on the vegetarian diet. There were no differences in plasma catecholamine, glucose or insulin levels sampled after breakfast on the two dietary regimes. CONCLUSIONS: The blood pressure-lowering effect of a lacto-ovovegetarian diet, which occurs throughout the working day, is associated with lower heart rates, suggesting a central nervous or cardiac mechanism. The possibility that the lower glycaemic index of a lacto-ovovegetarian diet has some effect needs to be investigated further in relation to major meal-times and studied in both normotensive and hypertensive subjects.

Adult↗
PubMed1993

Biochemical and neurohormonal responses to the introduction of a lacto-ovovegetarian diet.

OBJECTIVE: To assess the mechanisms of the blood pressure-lowering effect of a vegetarian diet in the early and later stages of dietary intervention. DESIGN: After 2 weeks without intervention (baseline), 20 normotensive men were matched for age and body mass index and randomly allocated to an omnivorous (control) or a lacto-ovovegetarian diet for 6 weeks in a parallel trial. METHODS: Ambulatory blood pressures were recorded between 0800 and 1700 h on alternate days during the first week of intervention, twice in the second week and weekly thereafter. Blood samples collected after a standard breakfast were analysed for plasma noradrenaline, adrenaline, atrial natriuretic peptide (ANP), renin, aldosterone, glucose and insulin. Factor and multiple regression analyses were used to assess the association among neurohormonal factors, blood pressures and diet. Results were analysed for the first week of the diet and for the entire 6 weeks. RESULTS: Ambulatory blood pressures at work were lower on the vegetarian diet than in the controls. This blood pressure decrease was associated with a factor representing lower plasma catecholamine and renin activity levels throughout the study, and a factor representing reduced plasma glucose and insulin levels in week 1 of intervention only. Plasma ANP levels were significantly higher during week 1 of the vegetarian diet. CONCLUSIONS: A blood pressure lowering effect of a vegetarian diet during normal working activity was shown. Using factors derived from the biochemical variables, results were in keeping with the hypothesis that these effects may be mediated by reduced sympatho-adrenal activity consequent to altered glucose and insulin handling. An early increase in plasma ANP may contribute to the blood pressure reduction.

Adult↗
PubMed1993

Inadequate recording of alcohol-drinking, tobacco-smoking and discharge diagnosis in medical in-patients: failure to recognize risks including drug interactions.

The records of 62 men and 43 women, 14-88 years old, admitted to general medical wards in a public teaching hospital during 1991 were examined for discharge medications and for the recording of alcohol-drinking, tobacco-smoking and discharge diagnosis. Drinking and smoking status was unrecorded in 22.9% and 21.9% of patients respectively. Twenty-four patients had 31 potential drug interactions which were related to the number of drugs prescribed and to drinking alcohol; 10.5% of the patients had interactions involving alcohol and 2.9% tobacco. Six patients received relatively or absolutely contraindicated drugs, including one asthmatic given two beta-blockers. The drugs prescribed indicated that some patients had conditions such as gastro-oesophageal disorders, diabetes and obstructive airways disease which had not been recorded. Inadequate recording of diagnoses, alcohol and smoking status creates risks to patients and may cause opportunities for preventive care to be missed. This study provides the basis for the development of undergraduate and postgraduate education programmes to address these issues and so decrease risks to patients which arise from inadequate recording practices. Incomplete diagnoses also adversely affect hospital funding where this depends on case-mix diagnostic groups. Quality assurance programmes and other strategies are being implemented to improve medical recording and prescribing habits.

Adolescent↗
PubMed1993

Effects on blood pressure of omega 3 fats in subjects at increased risk of cardiovascular disease.

This study was conducted to compare the effects of omega 3 fatty acids, taken as fish or fish-oil supplements in the setting of a high- or low-fat dietary background, on blood pressure and heart rate in men with moderate cardiovascular risks. One hundred twenty men were randomly allocated to five high-fat (40% of daily energy) and two low-fat (30% of energy) groups to undertaken a 12-week dietary intervention period involving fish, fish oil, or a combination of these. Sodium intake was restricted to less than 90 mmol/d. The five high-fat groups were assigned to take either 6 or 12 fish-oil capsules daily, fish or a combination of fish oil and fish, or placebo capsules. The two low-fat groups took either fish or placebo capsules. Fish meals were devised to provide 1.3 g of eicosapentaenoic acid daily, equivalent to that contained in 6 fish-oil capsules. Subjects were instructed to eat a selection of fish that provided an average of 3.65 g/d (range, 3.2 to 4.1 g/d) of total omega 3 fatty acids. Subjects were seen at regular intervals during the baseline and dietary intervention periods for measurement of weight, blood pressure, heart rate, dietary compliance, urinary electrolyte excretion, platelet phospholipid fatty acids, blood glucose, and insulin concentration. There was a greater fall in both systolic and diastolic blood pressures in subjects allocated fish or fish oil, particularly in the low-fat groups, compared with control subjects. However, there was no significant group effect.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Urine albumin excretion in healthy subjects.

The relationship between cardiovascular risk factors and urine albumin excretion were studied in 474 healthy office workers. Albumin concentration was measured fresh in first morning midstream urines. Lifestyle details, oscillometric BP and lipids were assessed. Subjects with urine albumin concentration above the median (5.30 mg/l) were compared with those with albumin concentration below the median. Subjects with above median urinary albumin concentration had higher systolic blood pressure (mean 115.2 vs. 113.1 mm Hg for above median, respectively, P = 0.06), were more likely to be male (56.8 vs. 45.0%, respectively, P = 0.01) and to have lower levels of high density lipoprotein (HDL)-cholesterol (mean 1.34 vs. 1.41 mmol/l, P = 0.006). Multivariate analysis following adjustment for urine creatinine concentration to allow for urine volume confirmed the relationship with systolic blood pressure (P = 0.01) and sex (P = 0.02), and in addition revealed a relationship with alcohol intake approaching significance (mean intake 70.8 and 76.0 g/week, respectively, P = 0.06). The univariate finding of increased albuminuria with lower HDL-cholesterol appeared to be attributable to the associated relationships with male sex and lower alcohol intake. The relationships between albumin excretion and BP, male sex and alcohol intake may reflect the effects of asymptomatic developing arterial disease. The relationship with BP may also be a consequence of effects on glomerular hydrostatic or interstitial renal pressure on albumin filtration or resorption. Very low level urine albumin excretion in healthy subjects is associated with factors which predict arterial disease. Urine albumin excretion may prove to be a useful early marker of cardiovascular disease in population studies.

Adolescent↗
PubMed1992

Association of lifestyle and personality characteristics with blood pressure and hypertension: a cross-sectional study in the elderly.

The association between certain lifestyle and personality characteristics and blood pressure in the elderly was assessed in a cross-sectional study of 843 independent living 60-87 year old volunteers. They comprised 338 women and 505 men of whom 35 and 30% respectively were being treated with antihypertensive drugs. Among untreated volunteers, 28% of women and 28% of men had systolic blood pressure greater than 160 or diastolic blood pressure greater than 95. Isolated systolic hypertension was found in 20% of untreated women and 14% of untreated men. Lifestyle factors and personality characteristics associated with blood pressure were similar to those described in younger adult populations, although there were some differences related to gender and whether subjects were being treated for hypertension. Stepwise multiple regression showed that higher blood pressure was associated with greater body mass index (BMI), alcohol intake and coffee drinking and measures of irritability. Increased physical activity, and high values for measures of suspicion and extraversion were negatively related to blood pressure. Age was positively related to systolic, but not to diastolic blood pressure. The presence of hypertension was significantly associated with self-reports of raised cholesterol, diabetes or angina, as well as past history of heart failure, heart attack or stroke. Thus, in this elderly free-living population blood pressures are still significantly associated with behavioural characteristics which could be further investigated as an alternative or adjunct to antihypertensive therapy.

Aged↗