A school-based intervention improved dietary intake outcomes and reduced waist circumference in adolescents: a cluster randomized controlled trial

Background

In Ecuador, adolescents’ food intake does not comply with guidelines for a healthy diet. Together with abdominal obesity adolescent’s inadequate diets are risk factors for non-communicable diseases. We report the effectiveness of a school-based intervention on the dietary intake and waist circumference among Ecuadorian adolescents.

Methods

A pair-matched cluster randomized controlled trial including 1430 adolescents (12–14 years old) was conducted. The program aimed at improving the nutritional value of dietary intake, physical activity (primary outcomes), body mass index, waist circumference and blood pressure (secondary outcomes). This paper reports: (i) the effect on fruit and vegetable intake, added sugar intake, unhealthy snacking (consumption of unhealthy food items that are not in line with the dietary guidelines eaten during snack time; i.e. table sugar, sweets, salty snacks, fast food, soft drinks and packaged food), breakfast intake and waist circumference; and, (ii) dose and reach of the intervention. Dietary outcomes were estimated by means of two 24-h recall at baseline, after the first 17-months (stage one) and after the last 11-months (stage two) of implementation. Dose and reach were evaluated using field notes and attendance forms. Educational toolkits and healthy eating workshops with parents and food kiosks staff in the schools were implemented in two different stages. The overall effect was assessed using linear mixed models and regression spline mixed effect models were applied to evaluate the effect after each stage.

Results

Data from 1046 adolescents in 20 schools were analyzed. Participants from the intervention group consumed lower quantities of unhealthy snacks (?23.32 g; 95% CI: ?45.25,-1.37) and less added sugar (?5.66 g; 95% CI: ?9.63,-1.65) at the end of the trial. Daily fruit and vegetable intake decreased in both the intervention and control groups compared to baseline, albeit this decrease was 23.88 g (95% CI: 7.36, 40.40) lower in the intervention group. Waist circumference (?0.84 cm; 95% CI: ?1.68, 0.28) was lower in the intervention group at the end of the program; the effect was mainly observed at stage one. Dose and reach were also higher at stage one.

Conclusions

The trial had positive effects on risk factors for non-communicable diseases, i.e. decreased consumption of unhealthy snacks. The program strategies must be implemented at the national level through collaboration between the academia and policy makers to assure impact at larger scale.

Trial registration

ClinicalTrial.gov-NCT01004367.

     

高吸水性树脂的合成研究

采用反相悬浮聚合法 ,运用两种不同的交联剂分阶段聚合 ,合成核壳型高吸水树脂。研究了反应温度、丙烯酸中和度、分散剂、交联剂及核壳比对吸水剂吸水性能的影响     

Toward quantum computation: a five-qubit quantum processor

Quantum physics presents intriguing possibilities for achieving computational gains after conventional miniaturization reaches its limits. Accordingly, we describe a nuclear magnetic-resonance quantum computer demonstrating a quantum algorithm that exponentially outperforms classical algorithms     

Distribution of salmonella strains in farrow-to-finish pig herds: a longitudinal study

The aims of this study were to investigate patterns of Salmonella shedding in finishing pigs and to study the role of the sow in the transmission of Salmonella to her offspring. In each of the three herds (A, B, and C), one cohort of sows (n = 34, n = 40, n = 32, respectively) together with three piglets of their offspring (n = 102, n = 120, n = 96, respectively) were selected. Individual fecal and blood samples were taken from the sows at different times during one production cycle and from the piglets from weaning until slaughter. At slaughter, contents from the jejunum, colon, and mesenteric lymph nodes were collected. Fecal samples, as well as the jejunum, colon, and mesenteric lymph node samples collected at slaughter, were submitted to a qualitative Salmonella analysis. Isolates were characterized by random amplified polymorphic DNA, and if necessary, further characterization was done by pulsed-field gel electrophoresis. In herds A and B, Salmonella shedding began in the nursery. A significant increase in the number of Salmonella shedders was seen after transferring pigs to the growing unit in herd B (P = 0.003) and to the finishing unit in herds A (P < 0.001) and B (P = 0.013). None of the fattening pigs in herd C were shedding Salmonella. This study reveals that transferring pigs is an important trigger to induce Salmonella shedding, leading to horizontal spread. Direct transmission of Salmonella from the sows to their piglets could not be demonstrated, but the similarities between the isolates found in the sows and those found during the nursery and finishing periods and at slaughter suggested indirect transmission.     

Processing practices contributing to Campylobacter contamination in Belgian chicken meat preparations

The aim of this study was to obtain insight into processing practices in the poultry sector contributing to the variability in Campylobacter contamination in Belgian chicken meat preparations. This was achieved by company profiling of eleven food business operators, in order to evaluate variation of processing management, in addition to statistical modelling of microbiological testing results for Campylobacter spp. contamination in 656 end product samples. Almost half (48%) of chicken meat preparation samples were positive for Campylobacter spp. Results revealed a statistically significant variation in Campylobacter contamination between 11 chicken meat producers across Belgium at both quantitative and qualitative detection levels. All producers provided Campylobacter-positive samples, but prevalence ranged from 9% up to 85% at single producer level. The presence or addition of skin during production of chicken meat preparations resulted in almost 2.2-fold increase in the probability of a sample being positive for Campylobacter, while chicken meat preparations made from frozen meat, or partly containing pre-frozen meat, had a significant (Odds Ratio=0.41; CI 95% 0.18:0.98) lower probability of being positive for Campylobacter. However, the quantitative results indicated that the positive freezing effect on Campylobacter count was compromised by the presence and/or adding of skin.     

Cadmium bioavailability and accumulation in the presence of humic acid to the zebra mussel, Dreissena polymorpha

Metal speciation in aquatic systems is mainly determined by the type and concentration of ligands present in solution. A very important group of complexing agents is dissolved organic matter (DOM), e.g., humic and fulvic acids. According to the free-ion activity model, only the free metal ion is available to biota. Nevertheless, DOM has been reported to decrease or increase metal uptake, leading to uncertainty concerning the bioavailability of metal-DOM complexes. In this work the effect of Aldrich humic acid on cadmium accumulation by the zebra mussel, Dreissena polymorpha, was studied under laboratory conditions. Mussels, collected in a drinking water reservoir, were exposed to varying environmentally relevant concentrations of cadmium in the presence and absence of humic acid. Cadmium concentrations in the mussel tissues were analyzed, and measurements with a cadmium-ion-selective electrode were made to determine the free cadmium ion activity in the exposure waters. The uptake of humic acid by the zebra mussels was measured by the decrease of the total organic carbon (TOC) concentration in the water over time. The free cadmium ion activity in the water decreased from 51.6% to 19.9% of the total cadmium concentration in the presence of humic acid. This decrease by a factor of 2.6 resulted in a decrease in the cadmium uptake rate in the soft tissue of zebra mussels from 12.9 to 7.9 nmol/g dry wt/day, which corresponds to a decrease by a factor of 1.6. This implies that cadmium uptake rates were higher than predicted by the free-ion activity model and indicates that cadmium-humic acid complexes are partly available to zebra mussels.     

Dynamic model for the accumulation of cadmium and zinc from water and sediment by the aquatic oligochaete, Tubifex tubifex

In aquatic environments, organisms are exposed to and accumulate metals via waterborne and dietary routes including ingested sediment. A key element in understanding metal uptake and accumulation is information concerning the relative importance of the routes of uptake and the kinetics of the processes. In this work the bioaccumulation of the essential element zinc and the nonessential element cadmium were studied from the aqueous and sediment phase, in the cosmopolitan oligochaete Tubifex tubifex, using the radiotracers 109Cd and 65Zn. A compartmental kinetic model was constructed and parametrized by fitting the model to metal body concentrations. Using the pharmacokinetic modeling approach and taking into account the distribution of the metal between water and sediment, the different routes were quantitatively separated. Under the experimental conditions, the sediment phase accounted for 9.8% of the cadmium and 52% of the zinc uptake. These values are based on the uptake of the radiotracers spiked sediments and therefore likely represent maximal values since it was shown that under the specific conditions this was the most mobile metal fraction. This difference was largely explained by the large difference in assimilation efficiency between cadmium and zinc. Simulations of different conditions showed that both dissolved and sediment-associated metal can be important sources of metal exposure for the worms and that the relative importance strongly depends on the metal and exposure conditions including the lability of the metals in the sediment phase.     

Survival of poultry-derived Campylobacter jejuni of multilocus sequence type clonal complexes 21 and 45 under freeze,chill, oxidative,acid and heat stresses

The application of multilocus sequence typing (MLST) for studying Campylobacter jejuni diversity reveals that MLST clonal complex (CC) 21 and CC-45 occupies significant proportion in the diverse population of C. jejuni. These two complexes are ecologically abundant and represent an interesting subpopulation for studying C. jejuni survival under different stress conditions. In the present study we characterize and compare 19 C. jejuni strains assigned to CC-21 and CC-45, isolated from chicken meat, based on laboratory stress models maintained in Muller-Hinton broth. Model conditions were mimicking freeze, chill, oxidative, acid and heat stresses. Results show that survival patterns varied between the strains. C. jejuni strains of CC-21 survived significantly better than C. jejuni strains of CC-45 under heat (P value = 0.022) and chill (P value = 0.001) stress models. On the other hand, C. jejuni strains of CC-45 showed significantly better survival compared to C. jejuni strains of CC-21 in response to oxidative (P value = 0.003) and freeze (P value = 0.021) stress models. C. jejuni strains assigned to the founder ST-45 showed significantly better survival (P value = 0.017) under heat stress model compared to their ancestral sequence types. However, an association between survival fitness and the diversification of a clonal group cannot be demonstrated directly from the obtained results. In conclusion, findings of the present study show that genotypic variations of C. jejuni might play a role in enabling certain lineages to be selected when encountering adverse and stressful environments. In future stress response studies, it is recommended to consider the effect of genotypic diversity among C. jejuni strains as that might bias the experimental findings.     

A tutorial on geometric programming

A geometric program (GP) is a type of mathematical optimization problem characterized by objective and constraint functions that have a special form. Recently developed solution methods can solve even large-scale GPs extremely efficiently and reliably; at the same time a number of practical problems, particularly in circuit design, have been found to be equivalent to (or well approximated by) GPs. Putting these two together, we get effective solutions for the practical problems. The basic approach in GP modeling is to attempt to express a practical problem, such as an engineering analysis or design problem, in GP format. In the best case, this formulation is exact; when this is not possible, we settle for an approximate formulation. This tutorial paper collects together in one place the basic background material needed to do GP modeling. We start with the basic definitions and facts, and some methods used to transform problems into GP format. We show how to recognize functions and problems compatible with GP, and how to approximate functions or data in a form compatible with GP (when this is possible). We give some simple and representative examples, and also describe some common extensions of GP, along with methods for solving (or approximately solving) them.