Management of lipids in rural Australia : are the guidelines being followed?

Background: Hypercholesterolaemia is ranked seventh among the major factors contributing to the overall burden of disease in Australia. Guidelines for evidence-based lipid management were released in 2001 and updated in 2005, however little population level data has been published on the current gap between recommended management and actual practice in Australia.

Method: Three population stratified surveys were undertaken in the Greater Green Triangle. Three thousand three hundred and twenty adults aged 25–74 years were randomly selected, stratified by gender and 10-year age groups. Anthropometric, clinical and self-administered questionnaire data relating to cardiovascular disease risk were collected in accordance with the WHO MONICA protocol. Blood samples were collected for lipid profile analysis. Participants were divided into four groups—Group 1: treated, high CVD risk; Group 2: treated, primary prevention; Group 3: untreated, high CVD risk; Group 4: untreated, low CVD risk. For each of these groups we compared cholesterol, HDL cholesterol, triglyceride and LDL cholesterol with targets recommended by the National Heart Foundation's 2005 guidelines.

Results: All lipids were at target in 39.4% of the study population with marked differences between groups: Group 1, 11.2%; Group 2, 38.5%; Group 3, 1.8%; Group 4, 47.6%.

Only 50.8% of the untreated high CVD risk group reported having blood cholesterol measured within the last 12 months.

Conclusion: Current rates of detection and treatment practices in rural Australia are suboptimal. Although one-third of the study population age 25–74 years are at sufficiently high risk to warrant consideration of lipid lowering medication only just over half of these were on treatment at the time of the study. These results suggest that an intensive implementation plan is required for the management of hyperlipidaemia in rural Australia.

Relationship of nutritional and metabolic factors to non-invasive indices of macrovascular disease in diabetes

Factors which may account for the high frequency of macrovascular disease in diabetics are age, sex, cigarette smoking, hypertension, obesity, lack of exercise, diet, hyperglycaemia, hyperinsulinaeroia, hypercholesterolaemia, hypertriglyceridaemia, low HDL-cholesterol concentration, elevated free fatty acid concentration and enhanced platelet aggregation. Twenty seven (13 men and 14 women) non-insulin-dependent diabetics and thirty eight age, height and weight matched healthy subjects (10 men and 28 women) were studied. None of the subjects were smokers, or hypertensive. No subject had any clinical evidence of peripheral arterial disease, coronary heart disease or cerebrovascular disease. All had apparently normal peripheral pulses and normal ankle/arm blood pressure indices. Methods for determining arterial compliance in the segment between the left subclavian artery and each common femoral artery, and proximal resistance at the common femoral artery and posterior tibial artery, have been reviewed and developed. An appropriate food intake methodology for deriving food indices from food records was developed. Biochemical determinants have been made of glucose tolerance, glycosylated haemoglobin, serum total cholesterol, HDL-cholesterol, LDL-cholesterol, triglyceride, plasma free fatty acid and insulin. A significant decrease in the arterial compliance, and a significant increase in the arterial proximal resistance at the common femoral artery and posterior tibial artery in non-insulin-dependent diabetics, compared with their healthy controls, have been found. Significant negative correlation between arterial compliance and proximal resistance and, a significant positive correlation between the arterial proximal resistance of common femoral artery and posterior tibial artery were found. Differences between control (healthy subjects) and non-insulin-dependent diabetic groups indicate that preclinical peripheral arterial disease can be recognised even in mild diabetics by non-invasive measurement of arterial compliance or proximal resistance. There were significant and negative correlations between arterial compliance and each of blood glucose, blood glycosylated haemoglobin (HbAlC), plasma free fatty acid and plasma insulin concentration. There were significant and positive correlations between arterial proximal resistance of common femoral artery and posterior tibial artery and each of blood glucose, glycosylated haemoglobin and plasma free fatty acid concentration. Multivariate analysis to examine each of the biochemical factors Including blood glucose, blood glycosylated haemoglobin (HbAlC), plasma free fatty acid, plasma Insulin and lipids, showed that the factor which most influenced the arterial compliance and the proximal resistance of posterior tibial artery was the glucose level in the fasting state or the glucose response after a glucose load. In addition, the factors which most influenced proximal resistance of the common femoral artery were free fatty acid -level in the fasting state or glucose response after a glucose load. The factors which most influenced arterial compliance were glucose level in men, and the insulin level in the fasting state or the plasma free fatty acid response after a glucose load in women. These findings indicate that blood glucose, plasma free fatty acid and plasma insulin are risk factors for changes in arterial wall characteristic at a stage when no clinical evidence of macrovascular disease is apparent. Arterial compliance was decreased and the proximal resistance of posterior tibial artery was increased in those with a low intake of protective foods compared with those with a high intake whether healthy subjects or non-insulin-dependent diabetics. Arterial compliance was decreased in non-fish eaters compared with the fish eaters whether healthy subjects or non-insulin-dependent diabetics. Proximal resistance of the posterior tibia! artery in non-fish eaters was increased compared with fish eaters in healthy subjects. Overall, food variety, a protective food score consumption and fish consumption emerge as importance determinants of arterial wall characteristics at a stage when no clinical evidence of macrovascular disease is apparent.

Effects of dietary constituents on coronary heart disease risk factors

Coronary Heart Disease (CHD) is a major cause of death in Western countries. Mediterranean and Asian populations have a lower risk of death from CHD compared to Westernised population, as do vegetarian versus omnivorous populations. Dietary constituents of traditional diets consumed by these populations are thought to influence both the classical risk factors for CHD, and the more recently identified risk factors, such as oxidative modification of low density lipoprotein (LDL), LDL particle size, arterial compliance and haemostatic factors. The aim of this thesis was to examine the effects of several food components, particularly soybean and monounsaturated fat (MUFA), on CHD risk factors through 3 carefully controlled dietary interventions, and a cross-sectional study. A randomised crossover dietary intervention study was conducted in 42 healthy males to investigate the effect on CHD risk factors of replacing lean meat with tofu, a soybean product regularly consumed by Asian populations, while controlling all other dietary factors. The tofu diet resulted in significantly lower total cholesterol and triacylglycerol levels compared to the lean meat diet, and LDL particles that were more resistant to in vitro oxidative modification. However, insulin, fibrinogen, factor VII, and lipoprotein (a) were not significantly different on the 2 diets. A postprandial study was subsequently conducted to investigate any acute effects of a tofu test meal on the oxidative modification of LDL in 16 male subjects. There was no significant difference between the susceptibility of LDL to oxidative modification before and after the tofu meal. Twenty eight healthy subjects completed a separate randomised crossover dietary intervention comparing a high MUFA fat diet, using an Australian high oleic sunflower oil, with a low fat, high carbohydrate diet on CHD risk factors. The high MUFA oil diet significantly increased high density lipoprotein cholesterol compared to the low fat diet as well as producing LDL that were more resistant to oxidative modification. Neither the size of the LDL particle nor arterial compliance were significantly different on the 2 diets. Twelve matched pairs of vegetations and omnivores were also studies to compare the habitual diet of a low and higher risk population group, to compare their risk factors and identify dietary constituents that may explain the differences. The vegetarians consumed less saturated fat (SFA) and dietary cholesterol while consuming more polyunsaturated fat, dietary fibre and vitamin E compared to omnivores. The vegetarians had lower total cholesterol, LDL cholesterol and triacylglycerol levels compared to the omnivores and had LDL particles that were more resistant to in vitro oxidation. These findings contribute to our knowledge about the dietary constituents that can alter some CHD risk factors in healthy subjects, and which could reduce the risk of developing CHD. Investigations in high risk groups might reveal even more benefits.

Effect of a stearic acid-rich, structured triacylglycerol on plasma lipid concentrations

Background: Structured lipids are being incorporated into foods to reduce their energy value. One such lipid is rich in stearic acid.
Objective: The objective of this study was to compare the effects on plasma lipids of a stearic acid–rich triacylglycerol and a fat rich in palmitic acid in hypercholesterolemic subjects.
Design: Fifteen subjects with an average plasma cholesterol concentration of 6.13 ± 0.80 mmol/L initially ate a low-fat diet for 2 wk (run-in period), followed in random order and blinded fashion by 2 high-fat diets (for 5 wk each) containing foods derived from margarines rich either in palmitic acid or in the structured, stearic acid–rich triacylglycerol.
Results: Plasma cholesterol concentrations with the low-fat, the stearic acid–rich, and the palmitic acid–rich diets were not significantly different (5.35 ± 0.83, 5.41 ± 0.78, and 5.52 ± 0.68 mmol/L, respectively) but were significantly lower (P < 0.001) than those measured during the habitual diet period (ie, 2 wk before the study began). Neither HDL cholesterol nor plasma triacylglycerol differed significantly among the 3 study diets.
Conclusion: A similar increase in the intake of stearic and palmitic acids (differing by <5% of total energy) to ensure a high fat intake resulted in plasma total and LDL-cholesterol concentrations that did not differ significantly from concentrations measured during a period of low-fat intake.

Arterial compliance, blood pressure, plasma leptin, and plasma lipids in women are improved with weight reduction equally with a meat-based diet and a plant-based diet

Obesity, strongly associated with the risk for coronary heart disease (CHD), is becoming increasingly prevalent. This study was designed to establish first whether systemic arterial compliance (SAC), an index of arterial function, is improved with weight loss and second, whether cardiovascular risk factors that improve with weight loss are reduced equally with lean meat or with an equivalent amount of plant protein in the diet. Thirty-six women, mostly overweight or obess, aged 40 ± 9 years, were allocated nonrandomly to a 16-week parallel-design trial of two equienergetic diets designed to lead to weight loss, with one arm of the study emphasizing red meat and the other soybeans as the major protein source. Body weight, waist and hip circumference, and plasma lipids, glucose, insulin, and leptin levels were measured, and SAC was calculated from ultrasound measurement of aortic flow velocity and aortic root driving pressure. Subjects lost weight (9% of body weight in 16 weeks) and showed decreased plasma total and low-density lipoprotein (LDL) cholesterol (12% and 14%, P < .0001, respectively), triacylglycerol (17%, P < .05), and leptin (24%, P < .01) concentrations. However, lipoprotein(a) [Lp(a)] levels did not change significantly. Mean arterial pressure (MAP) decreased 7% and SAC increased 28% (P < .001 for both). However, only the decrease in arterial pressure correlated significantly with the reduction in the waist to hip ratio (WHR), and the improvement in SAC correlated inversely with the blood pressure reduction (P < .001 for both). Further, weight loss and the metabolic benefits of weight loss occurred equally with the meat-based and plant-based diets. We conclude that moderate weight loss in women leads to a substantial reduction in the cardiovascular risk, including SAC.

Skipping breakfast : longitudinal associations with cardiometabolic risk factors in the childhood determinants of adult health study

Background: The long-term effects of skipping breakfast on cardiometabolic health are not well understood.

Objective: The objective was to examine longitudinal associations of breakfast skipping in childhood and adulthood with cardiometabolic risk factors in adulthood.

Design: In 1985, a national sample of 9–15-y-old Australian children reported whether they usually ate breakfast before school. During follow-up in 2004–2006, 2184 participants (26–36 y of age) completed a meal-frequency chart for the previous day. Skipping breakfast was defined as not eating between 0600 and 0900. Participants were classified into 4 groups: skipped breakfast in neither childhood nor adulthood (n = 1359), skipped breakfast only in childhood (n = 224), skipped breakfast only in adulthood (n = 515), and skipped breakfast in both childhood and adulthood (n = 86). Diet quality was assessed, waist circumference was measured, and blood samples were taken after a 12-h fast (n = 1730). Differences in mean waist circumference and blood glucose, insulin, and lipid concentrations were calculated by linear regression.

Results: After adjustment for age, sex, and sociodemographic and lifestyle factors, participants who skipped breakfast in both childhood and adulthood had a larger waist circumference (mean difference: 4.63 cm; 95% CI: 1.72, 7.53 cm) and higher fasting insulin (mean difference: 2.02 mU/L; 95% CI: 0.75, 3.29 mU/L), total cholesterol (mean difference: 0.40 mmol/L; 95% CI: 0.13, 0.68 mmol/L), and LDL cholesterol (mean difference: 0.40 mmol/L; 95% CI: 0.16, 0.64 mmol/L) concentrations than did those who ate breakfast at both time points. Additional adjustments for diet quality and waist circumference attenuated the associations with cardiometabolic variables, but the differences remained significant.

Conclusions: Skipping breakfast over a long period may have detrimental effects on cardiometabolic health. Promoting the benefits of eating breakfast could be a simple and important public health message.

Significant challenges remain to achieve risk reduction targets for cardiovascular secondary prevention and diabetes

Objective: To examine population-level evidence treatment gaps for cardiovascular risk among rural patients with existing cardiovascular disease or diabetes.

Methods: Three population surveys were undertaken in the Greater Green Triangle region of southeastern Australia 2004-2006. Adults aged 25-84 yrs were randomly selected using age/sex stratified electoral role samples. A representative 1690 participants were recruited (48% participation rate). Anthropometric, clinical and self-administered questionnaire chronic disease risk data were collected in accordance with the WHO MONICA protocol. Detailed investigation of cardiovascular and diabetes history, key cardiovascular risk factors, medication use and health behaviours were included.

Results: After adjusting for age and sex, an estimated 12% (sample n=272) of the population had one or more of coronary heart disease, stroke, or diabetes. Blood pressure was at target (<130/80 mmHg) for 26% of these individuals, and 61% were treated with antihypertensive medications. Lipid targets were achieved by 17% for total cholesterol (<4 mmol/L), 18% for LDL cholesterol (<2 mmol/L), 77% for HDL cholesterol (>1.0 mmol/L) and 44% for triglycerides (<1.5 mmol/L); overall 6% achieved all four lipid targets and 60% reported use of lipid-lowering therapy, including 51% overall using statins. Ten percent were current smokers, and four in every five patients (82%) had suboptimal BMI (outside the range 18.5 - 25.0).

Conclusions: All participants with uncontrolled blood pressure and most with uncontrolled lipids should be taking medications. The magnitude of evidence treatment gaps suggests existing models of care need fundamental reform and renewed focus on prevention.

The effect of short-term canola oil ingestion on oxidative stress in the vasculature of stroke-prone spontaneously hypertensive rats

Background: This study aimed to determine if 25 days of canola oil intake in the absence of excess dietary salt or together with salt loading affects antioxidant and oxidative stress markers in the circulation. A further aim was to determine the mRNA expression of NADPH oxidase subunits and superoxide dismutase (SOD) isoforms in the aorta of stroke-prone spontaneously hypertensive (SHRSP) rats.

Methods: Male SHRSP rats, were fed a defatted control diet containing 10% wt/wt soybean oil or a defatted treatment diet containing 10% wt/wt canola oil, and given tap water or water containing 1% NaCl. Blood was collected at the end of study for analysis of red blood cell (RBC) antioxidant enzymes, RBC and plasma malondialdehyde (MDA), plasma 8-isoprostane and plasma lipids. The aorta was removed and the mRNA expression of NOX2, p22phox, CuZn-SOD, Mn-SOD and EC-SOD were determined.

Results: In the absence of salt, canola oil reduced RBC SOD and glutathione peroxidase, and increased total cholesterol and LDL cholesterol compared with soybean oil. RBC glutathione peroxidase activity was significantly lower in both the salt loaded groups compared to the soybean oil only group. In addition, RBC MDA and plasma HDL cholesterol were significantly higher in both the salt loaded groups compared to the no salt groups. Plasma MDA concentration was higher and LDL cholesterol concentration lower in the canola oil group loaded with salt compared to the canola oil group without salt. The mRNA expression of NADPH oxidase subunits and SOD isoforms were significantly reduced in the canola oil group with salt compared to canola oil group without salt.

Conclusion: In conclusion, these results indicate that canola oil reduces antioxidant status and increases plasma lipids, which are risk factors for cardiovascular disease. However, canola oil in combination with salt intake increased MDA, a marker of lipid peroxidation and decreased NAPDH oxidase subunits and aortic SOD gene expression.

The role of reducing intakes of saturated fat in the prevention of cardiovascular disease : where does the evidence stand in 2010?

Current dietary recommendations advise reducing the intake of saturated fatty acids (SFAs) to reduce coronary heart disease (CHD) risk, but recent findings question the role of SFAs. This expert panel reviewed the evidence and reached the following conclusions: the evidence from epidemiologic, clinical, and mechanistic studies is consistent in finding that the risk of CHD is reduced when SFAs are replaced with polyunsaturated fatty acids (PUFAs). In populations who consume a Western diet, the replacement of 1% of energy from SFAs with PUFAs lowers LDL cholesterol and is likely to produce a reduction in CHD incidence of >2–3%. No clear benefit of substituting carbohydrates for SFAs has been shown, although there might be a benefit if the carbohydrate is unrefined and has a low glycemic index. Insufficient evidence exists to judge the effect on CHD risk of replacing SFAs with MUFAs. No clear association between SFA intake relative to refined carbohydrates and the risk of insulin resistance and diabetes has been shown. The effect of diet on a single biomarker is insufficient evidence to assess CHD risk. The combination of multiple biomarkers and the use of clinical endpoints could help substantiate the effects on CHD. Furthermore, the effect of particular foods on CHD cannot be predicted solely by their content of total SFAs because individual SFAs may have different cardiovascular effects and major SFA food sources contain other constituents that could influence CHD risk. Research is needed to clarify the role of SFAs compared with specific forms of carbohydrates in CHD risk and to compare specific foods with appropriate alternatives.

Chronic disease and impairment among Alaska native elders : the Alaska Education and Research Towards Health (EARTH) study

Background: Chronic diseases and impairments are prevalent among older Americans. However, prevalence data for Alaska Native (AN) elders are limited, with estimates usually extrapolated from national studies in which AN elders may not be well-represented. The aim of this study was to describe the prevalence of selected chronic diseases, impairments, and measured medical risk factors among a large community sample of AN elders.

Methods: Design, setting, and participants. A community-based cross-sectional study of baseline information from 656 AN elders aged 55 years or over who participated in the Alaska Education and Research Towards Health (EARTH) Study, March 2004 to August 2006. Measurements. Self-reported lifetime prevalence of 17 doctor-diagnosed chronic diseases, and point prevalence of vision, hearing, oral, and general health impairment were estimated from data collected using audio computer-assisted self-administered questionnaires. In addition, height, weight, blood pressure, fasting blood lipids, and fasting blood glucose levels were measured.

Results: The four most prevalent chronic diseases among AN elders were high blood pressure (55%), arthritis (49%), high cholesterol (42%), and adult bone fracture/break (35%). The median number of chronic diseases reported was three (inter-quartile range, 2 to 5). The prevalence of self-reported vision impairment was 15%, hearing impairment 18%, and having had all natural teeth removed 25%. Almost 50% were obese. High blood pressure (systolic ≥ 140 mm Hg and/or diastolic ≥ 90 mm Hg) was measured in 23%, high low density lipoprotein (LDL) cholesterol (≥ 130 mg/dL) in 39%, and high fasting plasma glucose (> 125 mg/dL) in 9%. Obesity was more prevalent among women than men. There were also significant regional differences in rates of obesity and high LDL cholesterol.

Conclusion: These data may be useful in public health programs and health services planning.

Daily eating frequency and cardiometabolic risk factors in young Australian adults : cross-sectional analyses

Eating frequency may be important in the development of overweight and obesity and other cardiometabolic risk factors; however, the evidence is inconsistent. The aim of the present study was to examine the associations between the number of eating occasions and cardiometabolic risk factors in a national population-based sample of young adults. A cohort of 1273 men and 1502 women, aged 26–36 years, completed a meal pattern chart to record when they had eaten during the previous day (in hourly intervals). The total number of eating occasions was calculated. Diet quality was assessed, waist circumference was measured and a fasting blood sample was taken. Dietary intake was compared with the Australian Guide to Healthy Eating. The associations between the number of eating occasions and cardiometabolic risk factors were calculated using linear regression. Analyses were adjusted for age, education and physical activity. Most men ate three to five times per d and most women ate four to six times. The proportion of participants meeting dietary recommendations increased with the number of eating occasions. For men, an additional eating occasion was associated with reductions in mean values for waist circumference ( − 0·75 cm), fasting glucose ( − 0·02 mmol/l), fasting insulin ( − 0·34 mU/l; 2·04 pmol/l), TAG ( − 0·03 mmol/l), total cholesterol ( − 0·08 mmol/l) and LDL-cholesterol ( − 0·06 mmol/l). Adjustment for waist circumference attenuated the results. Significant trends were not observed for women. In conclusion, a higher number of eating occasions were associated with reduced cardiometabolic risk factors in men. Many associations were mediated by waist circumference.

Dose-dependent effects of docosahexaenoic acid-rich fish oil on erythrocyte docosahexaenoic acid and blood lipid levels

Consumption of long-chain n-3 PUFA, particularly DHA, has been shown to improve cardiovascular risk factors but the intake required to achieve benefits is unclear. We sought to determine the relationship between DHA intake, increases in erythrocyte DHA content and changes in blood lipids. A total of sixty-seven subjects (thirty-six male, thirty-one female, mean age 53 years) with fasting serum TAG ≥ 1·1 mmol/l and BMI>25 kg/m² completed a 12-week, randomized, double-blind, placebo-controlled parallel intervention. Subjects consumed 2, 4 or 6 g/d of DHA-rich fish oil (26 % DHA, 6 % EPA) or a placebo (Sunola oil). Fasting blood lipid concentrations and fatty acid profiles in erythrocyte membranes were assessed at baseline and after 6 and 12 weeks. For every 1 g/d increase in DHA intake, there was a 23 % reduction in TAG (mean baseline concentration 1·9 (sem 0·1) mmol/l), 4·4 % increase in HDL-cholesterol and 7·1 % increase in LDL-cholesterol. Erythrocyte DHA content increased in proportion to the dose of DHA consumed (r 0·72, P < 0·001) and the increase after 12 weeks was linearly related to reductions in TAG (r − 0·38, P < 0·01) and increases in total cholesterol (r 0·39, P < 0·01), LDL-cholesterol (r 0·33, P < 0·01) and HDL-cholesterol (r 0·30, P = 0·02). The close association between incorporation of DHA in erythrocytes and its effects on serum lipids highlights the importance of erythrocyte DHA as an indicator of cardiovascular health status.

Light-intensity physical activity and cardiometabolic biomarkers in US adolescents

Authorised EU health claim for foods with a low or reduced content of saturated fatty acids

This chapter will evaluate the European Union (EU) approved health claim related to foods with low or reduced amounts of saturated fatty acids (SFAs) and maintenance of normal blood LDL-cholesterol concentrations, that was reviewed by the European Food Safety Authority (EFSA) in 2011 (EFSA, 2011). The characterisation of the food constituent, the scientific substantiation for the health claim and the conditions of use will be defined and evaluated. The wider impact of this claim will be discussed in relation to consumer issues, product development and future trends.