A controlled trial of health promotion programs in 11-year-olds using physical activity "enrichment" for higher risk children.

OBJECTIVE: To evaluate the short and long term benefits of a school and home based physical activity "enrichment" program for children at higher risk of cardiovascular disease as identified by cluster analysis. STUDY DESIGN: During two 10-week school terms, 800 11-year-olds took part in a randomized controlled trial with the standard physical activity and nutrition program in six schools, the standard program in a further seven schools but with the addition of physical activity enrichment for higher risk children in those schools, and no program in five control schools. Cluster analysis identifying the 29% or so highest risk children used systolic blood pressure, percent body fat, physical fitness, and blood cholesterol. RESULTS: Fitness improved significantly in program schools, particularly with enrichment in higher risk boys. Substantial improvements persisted 6 months later in girls from program schools. At "Enrichment" schools, cholesterol showed significant benefits in higher risk girls and, 6 months later, in both boys and higher risk girls. Sodium intake and, in girls, subscapular skinfolds were lower in "Enrichment" schools when the program ended, but not 6 months later. CONCLUSION: Two-semester health programs with physical activity enrichment for higher risk children can produce benefits sustained for at least 6 months. Improvements extend to lower risk children exposed indirectly to the enrichment. Attenuation of effects on diet and body composition in the longer-term suggest the need for on-going programs.

Differences in response to nutrition and fitness education programmes in relation to baseline levels of cardiovascular risk in 10 to 12-year-old children.

OBJECTIVE: To examine associations between children's responses to nutrition and fitness programmes and their baseline levels of cardiovascular risk factors. DESIGN: A randomised controlled trial. SETTING: Primary schools in Perth, Western Australia. PARTICIPANTS: 1147 children aged 10-12 years. INTERVENTIONS: Fitness, fitness+school nutrition, school +home nutrition or home nutrition programmes and a control group. MAIN OUTCOME MEASURES: Blood pressure (BP), cholesterol, nutrient intake, fitness, and body fat. RESULTS: Fall in systolic BP was significantly greater in the higher risk groups with the fitness intervention for boys and the home nutrition intervention for girls. Overall, diastolic BP fell for girls in the fitness intervention with no differences related to cluster membership. Higher risk boys in the fitness intervention showed greater improvement in fitness than the lower risk boys. Fitness improved in girls in the fitness programme but responses did not differ significantly according to cluster membership. Decrease in triceps skinfolds was significantly greater for higher risk boys in the home nutrition group and in higher risk girls except for those receiving the school+home nutrition intervention. Home nutrition programmes were associated with decreased intake of fat and greater intake of fibre in girls in the higher risk group and of sugar in higher risk boys. CONCLUSIONS: The greatest improvement in the higher risk children were associated with fitness and home nutrition programmes. Health education programmes aiming to include higher risk children should focus on these areas.

Effects of garlic extract on platelet aggregation: a randomized placebo-controlled double-blind study.

1. Studies of the effects of garlic on platelet aggregation have produced inconsistent results possibly related to variations in study design and in the garlic preparations used. 2. The present study examined the effects on platelet aggregation and serum thromboxane and lyso-platelet activating factor, of feeding garlic extract to healthy men using a placebo-controlled, double-blind design. The effects of the same garlic preparation on platelet aggregation in vitro were also investigated. 3. There were no significant differences in platelet aggregation with adenosine diphosphate, platelet activating factor (PAF) or collagen according to treatment group. Serum thromboxane and lysoPAF also showed no change related to garlic supplements. 4. In vitro aggregation with collagen decreased linearly with increasing amounts of garlic extract, but concentrations were higher than those attainable in vivo. Gastrointestinal side effects prevented the use of higher doses of garlic which must be considered to be pharmacological as they exceed changes achievable by dietary modification.

Plasma lipid levels and platelet and neutrophil function in patients with vascular disease following fish oil and olive oil supplementation.

This double-blind study was designed to examine and compare the effects of supplementing the existing diet with fish oil or olive oil on lipids and cell function in patients with peripheral vascular disease. Thirty-two patients with symptomatic and angiographically demonstrated peripheral vascular disease were screened, matched, and randomly allocated to take either 15 g/d fish oil or olive oil for 4 weeks. Fish oil reduced serum triglyceride levels by 26%, but increased total cholesterol levels due to a significant increase in both low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein-2 cholesterol (HDL2-C). There was a nonsignificant decrease in HDL3-C levels. Olive oil reduced total cholesterol levels, accountable to a significantly decrease in LDL-C levels. Serum thromboxane B2 (TXB2) levels remained unchanged following fish oil, but were significantly increased by olive oil. Urinary excretion of TXB2 and 6-keto-PGF1 alpha was unaffected by either oil supplement. Platelet aggregation, which was measured in platelet-rich plasma in response to two doses of collagen or platelet-activating factor (PAF), was significantly reduced after fish oil, but was increased by olive oil. Following fish oil, there was a significant increase in eicosapentaenoic acid (EPA, 20:5) and docosahexaenoic acid (DHA, 22:6) levels and a decrease in arachidonic acid content of platelet phospholipids. The platelet fatty acid composition after olive oil was unchanged. Fish oil decreased neutrophil leukotriene B4 (LTB4) generation following calcium ionophore stimulation by 33%, while leukotriene B5 levels increased significantly. Neutrophil PAF production and plasma lyso-PAF were unaffected by either oil.(ABSTRACT TRUNCATED AT 250 WORDS)

Relationships between blood pressure and measures of dietary energy intake, physical fitness, and physical activity in Australian children aged 11-12 years.

STUDY OBJECTIVE: The aim was to examine associations between blood pressure and dietary energy intake, physical activity, and physical fitness in Australian children. DESIGN: The study was a survey of year 7 children attending schools in metropolitan Perth. SETTING: Survey schools were located in suburbs representative of the range of socioeconomic strata in metropolitan Perth. PARTICIPANTS: Data were obtained on 1311 out of 2045 eligible children (64%). The sample included 681 boys and 630 girls. Mean age was 12.0 (SD 0.4) years. MEASUREMENTS AND MAIN RESULTS: Triplicate blood pressure measurements were obtained using a Dinamap oscillometric recorder. Dietary energy intakes were computed from two week day 24 h records. Physical activity was assessed using questionnaires. Physical fitness was measured using a shuttle run test. Additional measurements included weight, height, and skinfold thickness at four sites. A previous observation of an inverse relationship between diastolic blood pressure and dietary energy intake in boys was confirmed. There was evidence of an inverse relationship in girls but not in boys between blood pressure and physical activity. There was little evidence of relationships between blood pressure and physical fitness. CONCLUSIONS: Compared with weight and body mass index, dietary energy intake and the chosen measures of physical activity and physical fitness are poor predictors of blood pressure in the population studied.

Differential effect of aspirin on platelet aggregation in IDDM.

Diabetes mellitus is associated with a high incidence of cardiovascular diseases not directly attributable to hyperlipidemia, smoking, or hypertension, but which in part may be explained by an enhanced tendency to thrombosis due to increased platelet activity. The aim of this study was to evaluate platelet function and compare the effectiveness of the antiplatelet drug aspirin on platelet aggregation in diabetic and nondiabetic subjects. Platelet aggregation and composition were examined in 20 male insulin-dependent diabetes mellitus (IDDM) patients and 20 nondiabetic control subjects matched for age and body mass index. All were normotensive with serum total cholesterol less than 6.5 mM. Although within the clinically acceptable normal range, blood pressure was significantly higher in diabetic patients (130/75 mmHg) than in control subjects (123/70 mmHg) (P less than 0.05). Serum thromboxane B2 and ex vivo aggregation of platelets in response to two doses of the agonists collagen and platelet-activating factor (PAF) were similar to nondiabetic subjects. However, after taking 100 mg/day aspirin for 5 days, platelet aggregation to collagen was reduced by 76% in control subjects compared to 56% in IDDM patients (P less than 0.001). Aspirin treatment also reduced the slope of the aggregation curve and increased the lag time (the period between the addition of collagen and the start of irreversible aggregation) significantly more in control than in diabetic platelets. This difference in platelet aggregation could not be attributed to differences in platelet serotonin or thromboxane A2 secretion, the latter being almost completely suppressed by aspirin in each group. Platelet aggregation to PAF was similar in both groups and was not affected by aspirin.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of alcohol intake on plasma fatty acids assessed independently of diet and smoking habits.

1. This study was designed to determine prospectively whether changing alcohol consumption influenced the proportion of plasma linoleic acid independently of diet or smoking habits, and to evaluate changes in the plasma linoleic acid concentration as a potential marker of changes in alcohol consumption. 2. Fasting plasma fatty acid profiles were investigated in 72 male drinkers who were randomly assigned to drink low-alcohol beer or to maintain their usual drinking habits for a period of 4 weeks. 3. At entry to the study, a higher alcohol intake was associated with lower proportions of plasma linoleic acid, arachidonic acid and dihomolinolenic acid and higher proportions of plasma palmitoleic acid, independently of changes in body mass index. Smoking habits were unchanged and there were no major changes in diet during the period of the intervention. 4. Because the plasma palmitoleic acid concentration has been suggested as a possible marker of 'at risk' drinking, we investigated plasma fatty acid concentrations as indicators of alcohol intake. The plasma palmitoleic acid concentration was not a useful discriminator. Indices determined using logistic regression and combining plasma apolipoprotein A-II and linoleic acid concentrations gave better discrimination than either variable alone.

Reflotron cholesterol measurements in 1112 Australian children aged 10-12 years.

OBJECTIVE: To study the distribution of blood cholesterol concentration in a sample of Western Australian schoolchildren. DESIGN: The Reflotron dry-chemistry system (Boehringer Mannheim, Germany) was used to measure cholesterol in finger-prick blood samples obtained from Year 6 children aged 10-12 years attending government schools in metropolitan Perth. Recruitment methods ensured that children from different socioeconomic strata were represented. PARTICIPANTS: For the 1239 children enrolled in Year 6 in 30 government schools, parental consent to participate was obtained for 1144; of these cholesterol concentration was measured in 1112. RESULTS: The measurement method proved practicable and was generally well accepted. Cholesterol levels were somewhat lower than those obtained using a laboratory reference method and a bias, relative to national quality assurance standards, was estimated to be -0.32 mmol/L. Mean cholesterol level in boys (4.28 mmol/L, SD 0.69) was not significantly different from that in girls (4.35 mmol/L, SD 0.72). Allowing for measurement bias, 52% of boys and 57% of girls had cholesterol levels exceeding the National Heart Foundation's designated "desirable" level of 4.5 mmol/L for children. CONCLUSIONS: The distribution of cholesterol levels in Australian children compares unfavourably with distributions in children in countries with low rates of cardiovascular disease and indicates a need for widespread, appropriate diet and lifestyle changes.

Urinary steroid profiles and alcohol-related blood pressure elevation.

1. From an earlier cross-sectional survey of 343 public servants, 15 pairs of non-smoking teetotallers and heavy drinkers (alcohol intake more than 350 mL/week) were matched for age and adiposity and utilized for a case-control study of the effects of alcohol on 11 beta-hydroxysteroid dehydrogenase (11 beta-OHSD) activity and blood pressure. 2. Two successive 24 h urine collections were analysed by radio-immunoassay (RIA) for cortisol excretion, and for the cortisol and cortisone metabolites, tetrahydrocortisol (THC), allo-tetrahydrocortisol (allo-THC) and tetrahydrocortisone (THE), by capillary column gas chromatography. 3. Heavy drinkers had higher systolic and diastolic blood pressure (BP) than teetotallers (132.6 +/- 2.5 vs 123.2 +/- 1.3 and 78.7 +/- 1.6 vs 71.7 +/- 1.4, respectively; unpaired t-test, P less than 0.01). Twenty-four-hour urinary sodium and cortisol excretion were similar in the two groups. 4. The THC plus allo-THC:THE ratio was similar in drinkers and teetotallers (1.81 +/- 0.20 vs 2.03 +/- 0.20), consistent with no effect of alcohol on 11 beta-OHSD activity. The ratio of THC to allo-THC was increased in drinkers compared with teetotallers (1.49 +/- 0.18 vs 1.05 +/- 0.13; unpaired t-test, P less than 0.05), consistent with either a decrease in 5 alpha-reductase activity or an increase in 5 beta-reductase activity. 5. This study provides no evidence for alcohol-related inhibition of 11 beta-OHSD, despite substantially higher blood pressures in heavy drinkers compared to teetotallers. Such an effect is, therefore, unlikely to contribute significantly to the mechanism of alcohol-related hypertension.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of smoking cessation on serum apolipoprotein A-I and A-II concentrations.

This study investigated the effects of 6 weeks' smoking cessation on serum levels of total-cholesterol, triglyceride, high-density lipoprotein cholesterol (HDL-C) and apolipoproteins A-I and A-II (apo A-I and apo A-II) in 64 subjects of both sexes. Smoking cessation was associated with an increase in levels of apo A-II. Concurrent changes in weight and alcohol consumption during attempted smoking cessation, together with change in thiocyanate level, were entered as predictor variables into a multiple regression analysis. The change in apo A-II was found to be best accounted for by change in plasma thiocyanate level, and, in women, change in HDL-C and apo A-I by change in weight. The changes induced by smoking cessation may be due, at least in part, to associated changes in alcohol consumption and/or dietary intake, but in the case of apo A-II there is evidence of a more direct effect.

Comparison of diets supplemented with fish oil or olive oil on plasma lipoproteins in insulin-dependent diabetics.

This study was designed to compare changes in high-density lipoprotein (HDL)- and low-density lipoprotein (LDL)-cholesterol in normolipidaemic male insulin-dependent diabetics (IDD) following dietary supplementation with either the fish oil concentrate Max EPA or olive oil. The contribution of the small quantity of cholesterol in Max EPA to these changes was also examined. Twenty-seven subjects were matched in groups of three and randomly allocated to one of three treatment groups of nine subjects each. Subjects were given 15 1-g capsules of oil daily for 3 weeks, consisting of either Max EPA, olive oil, or olive oil to which was added the same amount of cholesterol as contained in Max EPA, respectively. There was a significant increase in eicosapentaenoic acid, and a decrease in arachidonic acid, in the platelet membrane phospholipids of subjects taking Max EPA. In this group, there was an approximately 30% increase in serum HDL2-cholesterol (0.59 +/- 0.07 to 0.77 +/- 0.11 mmol/L, mean +/- SEM; P less than .01) and a corresponding decrease in HDL3-cholesterol (0.79 +/- 0.03 to 0.71 +/- 0.03 mmol/L; P less than .05). Although total and LDL-cholesterol concentrations were also higher after Max EPA, the changes were not significant. Triglycerides were significantly decreased by Max EPA. There were no significant changes in lipids in the groups given olive oil. These results show that compared with olive oil, dietary supplementation with Max EPA substantially increases HDL2-cholesterol in insulin-dependent diabetics. This is most likely due to a selective effect of omega 3 fatty acids.(ABSTRACT TRUNCATED AT 250 WORDS)

Leukocyte and platelet function and eicosanoid production in subjects with hypercholesterolaemia.

A group of 22 subjects with type IIA hypercholesterolaemia (mean serum cholesterol = 8.3 +/- 0.3 mmol/l) were sex, age and weight matched with 22 control subjects (mean serum cholesterol = 4.5 +/- 0.1 mmol/l). Diastolic blood pressure was significantly higher in hypercholesterolaemic subjects (79.2 +/- 1.4 mm Hg) than in control subjects (71.9 +/- 1.4 mm Hg). While the high cholesterol group had 52% greater thromboxane production in clotted whole blood than controls this difference was not significant, and the platelet aggregation and serotonin secretion response to doses of collagen, ADP and arachidonic acid were similar between the 2 groups. Polymorphonuclear leukocyte (PMN) chemiluminescence (used as a measure of reactive oxygen species production) in response to low doses of the chemotactic-peptide FMLP and opsonized zymosan was significantly greater in high cholesterol subjects compared to their matched controls. The production of platelet activating factor (PAF) by calcium ionophore (2.5 micrograms) stimulated PMN isolated from hypercholesterolaemic subjects (11.5 +/- 1.4 ng/10(6) cells) was significantly greater than PAF production by cells from the control group (8.3 +/- 1.0 ng/10(6) cells). Leukotriene B4 release by PMN in response to calcium ionophore did not differ between the 2 groups. These data suggest a degree of leukocyte activation in hypercholesterolaemic subjects compared to controls with normal cholesterol. In addition, plasma levels of lyso-PAF were higher in high cholesterol subjects (317 +/- 21 ng/ml) compared to their matched controls (271 +/- 18 ng/ml) perhaps indicating increased plasma acetylhydrolase activity in subjects with raised cholesterol levels. Recently described biological activity for lyso PAF suggests a possible role for this substance in atherogenesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Fish oil-induced changes in apolipoproteins in IDDM subjects.

The aim of this study was to examine the effect of Max EPA (a commercially available fish oil preparation) on serum cholesterol lipoproteins and apolipoproteins in insulin-dependent diabetic (IDDM) men with dosages that were likely to be acceptable to patients. Twenty-two male IDDM patients aged 20-41 yr, 6 of whom had retinopathy, were recruited from the Royal Perth Hospital diabetic clinic. After screening, subjects were divided into three groups. Six of the subjects without retinopathy were randomly selected and allocated to a control group. The remaining 16 patients (10 without and 6 with retinopathy) received a fish oil supplement. All subjects were advised to maintain their usual dietary patterns. Sixteen patients, including the 6 with retinopathy, were instructed to take 15 Max EPA fish oil capsules/day with meals. Patients in the control group did not take Max EPA. Three weeks of Max EPA supplementation without other dietary modification led to a significant rise in total cholesterol (P less than 0.01), which could be accounted for by increases in low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol. The increase in HDL cholesterol was explained by a 33% rise (P less than 0.001) in its HDL2 subclass. Changes in apolipoproteins were examined and showed that the level of apolipoprotein A-I increased after ingestion of fish oil and correlated significantly (P less than 0.05) with the rise in HDL cholesterol.(ABSTRACT TRUNCATED AT 250 WORDS)

Whole blood aggregation and plasma lyso-PAF related to smoking and atherosclerosis.

1. Aggregation of diluted whole blood (impedance method) and thromboxane B2 production during aggregation were measured in cigarette smokers and non-smokers, aged 41-68 years, with (n = 14) and without (n = 15) major symptomatic peripheral vascular disease. The plasma level of the lyso derivative of platelet activating factor (lyso-PAF) was also measured using a bioassay with 14C-serotonin labelled rabbit platelets, after extraction and acetylation to active PAF. 2. Aggregation to ADP and collagen was significantly less in non-smokers without vascular disease (n = 8) than in the other three groups (P less than 0.01; ANOVA). Thromboxane B2 production was not significantly different between the groups. There was no significant difference in plasma lyso-PAF between groups. No change was found in any variable after smokers smoked two cigarettes. 3. In these older age subjects, both vascular disease and the smoking habit were associated with greater whole blood aggregation. However, current smoking and the smoking of two cigarettes did not affect aggregation in subjects with vascular disease and plasma lyso-PAF levels were not consistently related to either smoking or vascular disease.

Lifestyle- and occupation-related changes in blood pressure over a six-year period in a cohort of working men.

Determinants of change in blood pressure between two examinations separated by a 6-year period were investigated in 340 working men aged 20-45 at first examination and not on antihypertensive medication at either examination. A London School of Hygiene sphygmomanometer was used for all measurements of blood pressure. Relationships between change in blood pressure (residuals of follow-up blood pressure regressed on baseline blood pressure) and changes in weight, physical activity, cigarette smoking, diet, alcohol intake and a range of psychological characteristics were examined using multiple regression. Systolic and diastolic changes in blood pressure were both positively related to baseline age and weight. Regression equations indicated independent effects of change in weight, with similar increases of 0.5 (s.e. 0.1) mmHg in systolic and diastolic blood pressure for each kg of weight gain. Decreased coffee consumption and increased participation in sports were negatively associated with systolic changes in blood pressure. Men who had stopped smoking cigarettes were observed to have higher than average increases in both systolic and diastolic blood pressure, although these relationships were not independent of other variables. The difference in ambient temperature between baseline and follow-up measurement days was an important determinant of change. Changes in mean systolic and mean diastolic blood pressure in 76 manual workers (+10.1/+6.4 mmHg) compared unfavourably with changes in professional men (-2.8/+2.7 mmHg).(ABSTRACT TRUNCATED AT 250 WORDS)

Alcohol consumption, age and personality characteristics as important determinants of within-subject variability in blood pressure.

Intra-individual variability in blood pressure is well recognized but its determinants have been largely unexplored. In a recent cross-sectional study, 343 subjects from a male working population were assessed. Ten supine blood pressure readings were taken at 2-min intervals for 20 min on each of three consecutive days. Each subject's body mass index (weight/height2) was recorded and a questionnaire completed to record demographic details and information about physical activity, personality characteristics, dietary habits, tea and coffee consumption, smoking habits and alcohol consumption. When systolic and diastolic blood pressure variability was defined as the average coefficient of variation of the 10 readings each day, systolic blood pressure variability was found to be positively correlated with alcohol consumption, verbal aggression score and extroversion score. Diastolic variability was positively correlated with verbal aggression score, type-A personality score and extroversion score, and negatively associated with age. Stepwise regression analysis revealed alcohol consumption to be the strongest determinant of systolic variability while age was the strongest determinant of diastolic variability. We conclude that alcohol consumption, age and personality characteristics may be important determinants of intra-subject variability in blood pressure.

An appraisal of the effects of usual vs recent alcohol intake on blood pressure.

1. In a population-based study of 343 men from two public utilities, 260 subjects reported drinking alcohol at least once a week. In these subjects a comparison was made of the relative effects on blood pressure of either their usual alcohol intake (assessed from a 7-day retrospective diary) or recent alcohol intake (alcohol consumed at the last drinking session in the 24 h prior to blood pressure measurement). 2. Both usual and recent alcohol intake showed similar correlations with level of blood pressure (BP). After adjustment of BP for the potential confounding influences of body mass index, age and smoking status, systolic and diastolic BP remained highest in those subjects with the highest reported levels of both usual and recent alcohol intake. 3. In regression analyses comprising only those subjects who reported drinking in the 24 h before BP measurement, a 3-4 fold greater effect of usual rather than recent intake on both systolic and diastolic BP was predicted from the b coefficients. Regression analysis also demonstrated that the relationship between usual alcohol intake and BP was independent of recent intake, while the relationship between recent intake and BP was no longer significant when usual alcohol intake was entered into the regression equation. 4. These observations suggest that consistent regular drinking is a more important determinant of the alcohol/BP relationship than intake in the previous 24 h.

The effect of dietary fish oil and long-term salt loading on blood pressure and eicosanoid metabolism in spontaneously hypertensive rats.

1. Dietary suppression of prostanoid synthesis with fish oils has had little effect on blood pressure in models of experimental hypertension in rats. However, a pressor effect of dietary fish oils was observed in spontaneously hypertensive rats (SHR) subject to 1 week of salt loading. 2. Animals were allocated to semisynthetic diets containing either 10% by weight Max EPA fish oil or a control diet of coconut oil, and studied after receiving 1.5% saline for 4 weeks. 3. Within the first week of salt loading, SHR-fed fish oil showed an increase in blood pressure (mean = 9 mmHg) relative to controls. This effect was transient, and after the first week of salt loading there was little difference in blood pressure between the two dietary groups. 4. Following dietary treatment there were substantial changes in plasma fatty acid composition with a 48% decrease in arachidonic acid content of fish oil-fed rats compared with control animals. Rats on the fish oil diet showed a threefold decrease in serum thromboxane generation. Prostacyclin production by incubated segments of aorta was reduced by more than 50% compared with the coconut oil-fed control group. 5. SHR on the fish oil diet showed increased urine volume and sodium excretion, presumably due to increased fluid and salt intake. 6. This study shows that dietary suppression of prostacyclin synthesis is associated with only a minor effect on blood pressure in long-term salt loading of SHR.

Time dependence of whole blood aggregation in response to platelet activating factor (PAF).

The aggregation/adhesion response to platelet activating factor (PAF) was studied in diluted whole blood by impedance aggregometry. The extent of aggregation varied directly with the interval between blood sampling and aggregation measurement over the first 30 minutes from sampling, then remained stable for the next 60 minutes of observation. This is an effect opposite to that described for aggregation to PAF in platelet rich plasma which, however, cannot be studied soon after sampling. Time dependence of aggregation is important and comparative measurements should be made during the period of stable aggregability.