A plastic scintillator and HPGe ß-γ coincidence detection system.

A network of specialist laboratories support the International Monitoring System (IMS) of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) with re-measurements of radionuclide samples, including xenon gas. The measurement of four xenon fission product radionuclides (133Xe, 135Xe, 131mXe and 133mXe) can be used to detect an underground nuclear explosion. Laboratories use a range of techniques to measure the radionuclides, including beta-gamma (ß-γ) coincidence spectrometry. These highly-sensitive measurements are capable of detecting concentrations of down to 500 atoms of 133Xe in a few cm3 of xenon. In some detector systems, detection of the metastable isomers (131mXe and 133mXe) can be more challenging due to interferences between the signatures of different radionuclides. Recent work has shown that using high-purity Germanium (HPGe) high-resolution gamma detectors, these interferences can be reduced, lowering the dependence of the detection limits on radionuclide sample isotopic composition. One downside of these detectors is the reduction in detection efficiency, which impacts the overall detection sensitivity; so assessing different detector systems is a priority for radionuclide laboratories. This work presents a coincidence detector system comprising of a plastic scintillator gas cell and a large-crystal high-purity germanium detector. The energy resolution, coincidence detection efficiency, MDA and interference factors are determined from measurements of synthetic radioxenon gas samples.

A systematic methodology to estimate added sugar content of foods.

BACKGROUND/OBJECTIVES: The effect of added sugar on health is a topical area of research. However, there is currently no analytical or other method to easily distinguish between added sugars and naturally occurring sugars in foods. This study aimed to develop a systematic methodology to estimate added sugar values on the basis of analytical data and ingredients of foods. SUBJECTS/METHODS: A 10-step, stepwise protocol was developed, starting with objective measures (six steps) and followed by more subjective estimation (four steps) if insufficient objective data are available. The method developed was applied to an Australian food composition database (AUSNUT2007) as an example. RESULTS: Out of the 3874 foods available in AUSNUT2007, 2977 foods (77%) were assigned an estimated value on the basis of objective measures (steps 1-6), and 897 (23%) were assigned a subjectively estimated value (steps 7-10). Repeatability analysis showed good repeatability for estimated values in this method. CONCLUSIONS: We propose that this method can be considered as a standardised approach for the estimation of added sugar content of foods to improve cross-study comparison.

Higher regular fat dairy consumption is associated with lower incidence of metabolic syndrome but not type 2 diabetes.

BACKGROUND AND AIMS: Limited evidence suggests habitual dairy consumption to be protective against metabolic syndrome (MetSyn) and type 2 diabetes among older adults. We assessed the association of baseline consumption of dairy products with the incidence of MetSyn and type 2 diabetes among a cohort of Australian adults aged 49 years and over. METHODS AND RESULTS: A validated 145-item semi-quantitative food frequency questionnaire was used to assess food and nutrient intake at baseline. Ten-year incidence of MetSyn and type 2 diabetes were obtained from 1807 and 1824 subjects respectively. Odds ratios (OR) were calculated by discrete time logistic regression modelling. Compared with subjects in the lowest intake quartile of regular fat dairy products, those in the highest quartile had a 59% lower risk of MetSyn (multivariate adjusted OR: 0.41; 95% CI: 0.23-0.71; p(trend) = 0.004), after adjustment for risk factors. Among obese subjects, an association between a high intake of regular fat dairy foods and reduced risk of type 2 diabetes was also found (age and sex adjusted OR 0.37; 95% CI: 0.16-0.88; p(trend) = 0.030), but the association did not persist after adjustment for additional confounders. There was no association between total dairy consumption and risk of MetSyn or type 2 diabetes. CONCLUSIONS: We found an inverse association between regular fat dairy consumption and risk of MetSyn among Australian older adults. Further studies are warranted to examine the association between weight status, dairy consumption and risk of type 2 diabetes.

Consumer response to healthy eating, physical activity and weight-related recommendations: a systematic review.

Strong evidence linking poor diet and lack of physical activity to risk of obesity and related chronic disease has supported the development and promotion of guidelines to improve population health. Still, obesity continues to escalate as a major health concern, and so the impact of weight-related guidelines on behaviour is unclear. The aim of this review was to examine consumer response to weight-related guidelines. A systematic literature search was performed using Medline, PsycInfo, ProQuest Central and additional searches using Google and reference lists. Of the 1,765 articles identified, 46 relevant titles were included. Most studies examined attitudes towards content, source, tailoring and comprehension of dietary guidelines. Many respondents reported that guidelines were confusing, and that simple, clear, specific, realistic, and in some cases, tailored guidelines are required. Recognition of guidelines did not signify understanding nor did perceived credibility of a source guarantee utilization of guidelines. There was a lack of studies assessing: the impact of guidelines on behaviour; responses to physical activity guidelines; responses among males and studies undertaken in developing countries. Further research is needed, in particular regarding responses to physical activity guidelines and guidelines in different populations. Communication professionals should assist health professionals in the development of accurate and effective weight-related guidelines.

The effect of dairy consumption on blood pressure in mid-childhood: CAPS cohort study.

BACKGROUND/OBJECTIVES: It has been postulated that a higher dairy consumption may affect blood pressure regulation. The aim of this study was to examine the association between dairy consumption and blood pressure in mid-childhood. SUBJECTS/METHODS: Subjects (n = 335) were participants of a birth cohort at high risk of asthma with information on diet at 18 months and blood pressure at 8 years. Multivariate analyses were used to assess the association of dairy consumption (serves) and micronutrient intakes (mg). In a subgroup of children (n = 201), dietary intake was also measured at approximately 9 years. RESULTS: Children in the highest quintile of dairy consumption at 18 months had lower systolic blood pressure (SBP) and diastolic blood pressure (DBP) at 8 years (2.5 mm Hg, P=0.046 and 1.9 mm Hg, P = 0.047, respectively) than those in the lowest quintiles. SBP was lowest among children in the highest quintiles of calcium, magnesium and potassium intakes. Significant negative linear trends were observed between SBP and intakes of dairy serves, calcium, magnesium and potassium. Furthermore, SBP and DBP were lowest in the group of children that consumed at least two dairy serves at both 18 months and the follow-up dietary data collection at 9 years, compared with all other children (SBP 98.7 vs 101.0 mm Hg, P = 0.07; and DBP 56.5 vs 59.3 mm Hg, P = 0.006, respectively). CONCLUSION: These results are consistent with a protective effect of dairy consumption in childhood on blood pressure at age 8 years.

Changes in core food intake among Australian children between 1995 and 2007.

BACKGROUND/OBJECTIVES: To assess the changes in the consumption of core foods among Australian children between the 1995 National Nutrition Survey (1995 NNS) and the 2007 Australian National Children's Nutrition and Physical Activity Survey (2007 Children's Survey). SUBJECTS/METHODS: Core food consumption was analysed using 24-h recall data from 2-16 year old children using the 1995 NNS (n=2435) and the 2007 Children's Survey (n=4380). Differences in percent consuming, amounts consumed and percent energy contribution were assessed. RESULTS: The consumption of core foods increased significantly between the 1995 and 2007 surveys, including per-capita consumption and percent energy contribution (both P0.001). Core foods contributed to 59% of energy intake in 1995 compared with 65% in 2007. The types of core foods consumed also changed during this time period with more children reporting eating healthy options such as wholemeal bread, reduced-fat milk, reduced-fat cheese and fruit in the 2007 Children's Survey. Conversely, the consumption of white bread, full-fat milk and low-fibre breakfast cereals was lower in 2007. CONCLUSIONS: Overall, reported dietary intake had improved from 1995 to 2007 among Australian children with an increase in the amounts of core foods consumed and healthier types of foods being chosen. Continued health-promotion activities and monitoring of food consumption are highly warranted.

Dairy consumption and overweight and obesity: a systematic review of prospective cohort studies.

A comprehensive literature search was undertaken to examine the relationship between dairy consumption and overweight/obesity in prospective cohort studies. A literature search from 1980 through to April 2010 was conducted. Nineteen cohort studies met all the inclusion criteria and were included in the systematic review. Of the 19 cohort studies, 10 were among children and adolescents (aged 2 to 14 years, n = 53 to 12,829, follow-up 8 months to 10 years) and nine among adults (aged 18 to 75 years, n = 248 to 42,696, follow-up 2 years to 12 years). A range of dairy food exposure measures were used. Eight studies (three out of 10 studies involving children and five out of nine studies involving adults) showed a protective association against increasing weight gain (measured in various ways); one reported a significant protective association only among men who were initially overweight; seven reported no effect; one reported an increased risk (among children), and two reported both a decreased and increased risk, depending on the dairy food type. The evidence from prospective cohort studies for a protective effect of dairy consumption on risk of overweight and obesity is suggestive but not consistent, making firm conclusions difficult.

Consumption of 'extra' foods by Australian adults: types, quantities and contribution to energy and nutrient intakes.

OBJECTIVES: To identify the types and quantities of 'extra' foods, or energy-dense, nutrient-poor foods, consumed by Australian adults, and assess their contribution to total energy and nutrient intakes. SUBJECT/METHODS: We used 24-h recall data from 10 851 adults, aged 19 years and over, who participated in the nationally representative 1995 National Nutrition Survey. 'Extra' foods were defined using principles outlined in the Australian Guide to Healthy Eating and by applying cut points for maximum amounts of fat and sugar within each food category. RESULTS: 'Extra' foods contributed to 36% of daily energy intake with the highest contributors being fried potatoes (2.8%), margarine (2.6%), cakes and muffins (2.5%), beer (2.4%), sugar-sweetened soft drinks (2.4%), and meat pies (2.2%). Both age and sex were important determinants of 'extra' foods intake; younger adults were more likely to consume sugar-sweetened soft drinks, fried potatoes, meat pies and savoury pastries, pizza, crisps, lollies and chocolate; whereas older adults were more likely to consume sweet and savoury biscuits, cakes and muffins, margarine and butter. In all age groups, 'extra' foods contributed more to energy intake for men than women. Overall, 'extra' foods contributed 16% protein, 41% total fat, 41% saturated fat, 47% sugar and approximately 20% of selected micronutrients to the diet. CONCLUSIONS: 'Extra' foods contribute excessively to the energy, fat and sugar intakes of Australian adults, while providing relatively few micronutrients. This is of concern for the increasing risk of overweight and chronic disease and poor micronutrient status.

Consumption of 'extra' foods by Australian children: types, quantities and contribution to energy and nutrient intakes.

OBJECTIVE: To measure the types and quantities of energy-dense, nutrient-poor 'extra' foods consumed by Australian children and adolescents and their contribution to total energy and nutrient intakes. DESIGN, SETTING AND SUBJECTS: We used data from 3007 children, aged 2-18 years, who participated in the nationally representative 1995 National Nutrition Survey. Intake was determined by 24-h recall and 'extra' foods were defined using principles outlined in the Australian Guide to Healthy Eating (AGHE) and by applying cut points for maximum amounts of fat and sugar within each food category. RESULTS: All children (99.8%) consumed at least one 'extra' food and the most commonly consumed were margarine, sugar-sweetened soft drinks, cordials and sugar. 'Extra' foods contributed 41% of daily energy intake. Those foods contributing most to energy intake were fried potatoes (4.2%), sugar-sweetened soft drinks (3.3%), ice cream/ice confection (3.1%) and cordials (2.7%). Age and sex were important determinants of 'extra' food intake, with males and older children generally consuming more and different types of, 'extra' foods than females and younger children. 'Extra' foods contributed 19% protein, 47% total fat, 47% saturated fat, 54% sugar, and approximately 20-25% of selected micronutrients to the diet. Calcium and zinc intakes from core foods were below 70% of the recommended dietary intakes for adolescent girls. CONCLUSIONS: 'Extra' foods are over-consumed at two to four times the recommended limits and contribute excessively to the energy, fat and sugar intakes of Australian children, while providing relatively few micronutrients. This is of concern in terms of children's weight and nutrient status.

Plasma leptin is associated with insulin resistance independent of age, body mass index, fat mass, lipids, and pubertal development in nondiabetic adolescents.

OBJECTIVE: The rising epidemic worldwide in overweight and obese children requires urgent attention. Leptin has been found to be associated with body weight control and possibly affects insulin sensitivity. Since insulin resistance is associated with obesity in adults and possibly in adolescents, we set out to investigate the association of plasma leptin level with various anthropometric indices, body fat mass (FM), lipids, and insulin resistance (IR) index in nondiabetic adolescents. DESIGN: A cross-sectional study from three high schools in Taipei City in Taiwan. SUBJECTS: A total of 402 nondiabetic subjects (162 boys and 240 girls; age range, 10-19 y; mean age, 15.8+/-1.9 y, and mean body mass index (BMI), 24.8+/-4.6 kg/m(2)) were recruited. MEASUREMENTS: The fasting plasma leptin, plasma glucose, insulin, lipids, and anthropometric indices including height, weight, waist (WC) and hip circumferences, and waist-to-hip ratio (WHR) were examined. Total body FM and percentage body fat (FM%) were obtained from dual-energy X-ray absorptiometry. The homeostasis model was applied to estimate the degree of IR. RESULTS: The plasma leptin levels were significantly higher in girls (17.45+/-10.13 ng/ml) than boys (8.81+/-6.71 ng/ml, P<0.001). The plasma leptin levels were positively correlated to BMI, WC, WHR, FM, FM%, and triglycerides (TG). The IR index was positively correlated to BMI, WC, WHR, FM, FM%, TG, and leptin. Using the multivariate linear regression models, we found that plasma leptin remains significantly associated with IR index even after adjusting for age, gender, BMI, FM, WC, Tanner stage, and TG. CONCLUSION: Plasma leptin was associated with IR index independent of age, gender, BMI, FM, WC, Tanner stage, and TG. Plasma leptin levels in adolescents could be a predictor for the development of the metabolic syndrome disorders and cardiovascular diseases.

Cardiovascular risk in the Asia-Pacific region from a nutrition and metabolic point of view: abdominal obesity.

The level of obesity within the Pacific Islands is extremely high and so is the prevalence of weight-related morbidity and mortality. In contrast, the level of obesity, as defined by the standard WHO classification, remains relatively low in most Asian countries, yet rates of obesity-related disease, such as diabetes and cardiovascular disease are increasing rapidly. Many Asian races appear to be susceptible to the development of excessive abdominal fatness, even at low levels of body mass index (BMI). In addition, the health consequences of weight gain appear to occur at much lower levels of BMI and are more intense than in those of European origin. The exact reasons for these ethnic variations in the development of coronary heart disease (CHD) remain unclear. It is likely that genetic differences contribute to this variation in CHD risk, but different dietary and physical activity patterns may also play a role. The advent of modernisation has resulted in marked changes in the level of physical activity and the food supply available throughout the Asia-Pacific region. There has been a shift towards higher intakes of fats (particularly animal fats and vegetable oils) and sugars. Urbanisation and occupational restructuring have reduced daily physical activity levels. As a result, the population mean BMI and consequent illness is increasing in many countries within the region. Recent studies have shown that infants who were undernourished in utero and then born small have a greater risk of developing abdominal obesity and related morbidity as adults. As undernutrition coexists with overnutrition throughout the Asia-Pacific, focusing efforts to improve nutrition during pregnancy will need to be combined with programs to prevent weight gain in adults if CHD and other chronic diseases are to be effectively tackled in the region.

The global epidemic of obesity.

Obesity is at last being recognized as a major public health problem of global significance. More quality national obesity prevalence data are urgently needed but it is clear that rates are already high and increasing in most parts of the world. Current estimates of the global prevalence exceed 250 million. The first formal World Health Organization Consultation on obesity concluded that the global epidemic is an unintended consequence of modernization, economic development, urbanization and other societal changes. These have led to widespread reductions in spontaneous and work-related physical activity and to excessive consumption of energy dense foods. Links between reduced growth in utero and increased risk of ill health in later life may partly explain why populations in many developing countries are especially susceptible to obesity, diabetes and heart disease when exposed to modern sedentary living. The International Obesity TaskForce has launched a global initiative for coherent action to tackle the epidemic.

Key issues in the prevention of obesity.

Obesity is a serious, chronic medical condition which is associated with a wide range of debilitating and life-threatening conditions. It imposes huge financial burdens on health care systems and the community at large. Obesity develops over time and once it has done so, is difficult to treat. Therefore, the prevention of weight gain offers the only truly effective means of controlling obesity. Very little research has directly addressed the issue of obesity prevention and previous efforts to prevent obesity amongst individuals, groups or whole communities have had very limited success. However, we have learned sufficient from past preventive activities to realise that the management of obesity will require a comprehensive range of strategies with actions that target those with existing weight problems, those at high risk of developing obesity as well as the community as a whole. The prevention and management of obesity in children should be considered a priority as there is a high risk of persistence into adulthood.

Factors associated with successful risk reduction after a community coronary risk factor screen.

Debate continues over the effectiveness of coronary risk factor screening as a strategy for the prevention of coronary heart disease in the community. We reviewed changes in risk factors one year after a community coronary risk factor screen and found highly significant reductions in the blood cholesterol (mean reduction of 0.6 mmol/l) and body mass index (mean reduction of 1.03 kg/m2) in those participants who at the initial screening were found to have elevated (greater than 6.5 mmol/l) blood cholesterol concentrations. Comparison of this group with a reference group not given health advice and a group of hypercholesterolaemic clinic attenders showed that the blood cholesterol reduction could not be accounted for solely by regression to the mean, and was as good as the blood cholesterol reduction achieved by regular clinic attendance. Although there were many factors that could account for these reductions, we found that participants who received risk factor measurement and counselling during the screening process and who sought medical follow-up after the screen had a greater reduction in risk factors.

Risk factors for coronary heart disease in a self-referred population compared with a general population.

Screening programmes for community coronary heart disease risk factors aim to identify persons who are at a high risk of the development of coronary heart disease by screening the population for the prevalence of smoking, obesity, high blood pressure and high blood cholesterol concentrations. The effectiveness of such screening programmes is dependent on a number of factors. The characteristics of individuals who attend such screening programmes voluntarily, and the prevalence of abnormal coronary heart disease risk factors that is detected, give a strong indication of the population reach and the potential benefits of the preventive strategy. In this study, persons who attended a self-referred risk-factor screening programme for coronary heart disease were compared with a random sample of the Australian urban population. A disproportionately high number of older persons and of women presented for the self-referred screening programme while smokers were underrepresented. In general, the risk-factor levels of those in the older age-groups who attended the screening programme were lower than were the corresponding measurements that were found in the random sample; the opposite was true for those in the younger age-groups. These results suggest that coronary heart disease risk-factor screening programmes in the community appeal more to those in the health-conscious older age-groups and to women. For heart disease prevention programmes to be more effective, it will be necessary to design screening programmes to attract more men, those in younger age-groups and smokers.