Population dynamics of rice planthoppers, Nilaparvata lugens and Sogatella furcifera (Hemiptera, Delphacidae) in Central Vietnam and its effects on their spring migration to China

Rice planthopper (RPH) populations of Nilaparvata lugens and Sogatella furcifera periodically have erupted across Asia. Predicting RPH population dynamics and identifying their source areas are crucial for the management of these migratory pests in China, but the origins of the migrants to temperate and subtropical regions in China remains unclear. In particular, their early migration to China in March and April have not yet been explored due to a lack of research data available from potential source areas, Central Vietnam and Laos. In this study, we examined the population dynamics and migratory paths of N. lugens and S. furcifera in Vietnam and South China in 2012 and 2013. Trajectory modeling showed that in March and April in 2012 and 2013, RPH emigrated from source areas in Central Vietnam where rice was maturing to the Red River Delta and South China. Early migrants originated from Southern Central Vietnam (14-16°N), but later most were from Northern Central Vietnam (16-19°N). Analysis of meteorological and light-trap data from Hepu in April (1977-2013) using generalized linear models showed that immigration increased with precipitation in Southern Central Vietnam in January, but declined with precipitation in Northern Central Vietnam in January. These results determined that the RPH originate from overwintering areas in Central Vietnam, but not from southernmost areas of Vietnam. Winter precipitation, rather than temperature was the most important factor determining the number of RPH migrants. Based on their similar population dynamics and low population densities in Central Vietnam, we further speculated that RPH migrate to track ephemeral food resources whilst simultaneously avoiding predators. Migrations do not seem to be initiated by interspecific competition, overcrowding or host deterioration. Nevertheless, S. furcifera establishes populations earlier than N. lugens South China, perhaps to compensate for interspecific competition. We provide new information that could assist with forecasting outbreaks and implementing control measures against these migratory pests.

Hypertensive disorders of pregnancy in women with gestational diabetes mellitus on overweight status of their children

Hypertensive disorders of pregnancy (HDP) as a group of medical complications in pregnancy are believed to be associated with an increased risk of poor fetal growth, but the influence on offspring’s body composition is not clear. The aim of the present study was to evaluate the association between maternal hypertensive disorders of pregnancy and overweight status in the offspring of mothers with gestational diabetes mellitus (GDM).

A cross-sectional study among 1263 GDM mother-child pairs was performed in Tianjin, China. General linear models and logistic regression models were used to assess the associations of maternal hypertension in pregnancy with anthropometry and overweight status in the offspring from birth to 1–5 years old.

Offspring of GDM mothers who were diagnosed with hypertensive disorders during pregnancy had higher mean values of Z scores for birth weight for gestational age and birth weight for length, and higher mean values of Z scores for weight for age, weight for length/height, and body mass index for age at 1–5 years old than those of GDM mothers with normal blood pressure during pregnancy. Maternal hypertensive disorders of pregnancy were associated with increased risks of large for gestational age (OR 1.74, 95%CI 1.08–2.79) and macrosomia (OR 2.02, 95%CI 1.23–3.31) at birth and childhood overweight/obesity at 1–5 years old age (OR 1.88, 95%CI 1.16–3.04).

For offspring of mothers with GDM, maternal hypertension during pregnancy was a risk factor for macrosomia at birth and childhood overweight and obesity, and controlling the maternal hypertension may be more important for preventing large for gestational age babies and childhood obesity.

Degradation of methomyl by the combination of Aminobacter sp. MDW-2 and Afipia sp. MDW-3

Methomyl (S-methyl N-(methylcarbamoyloxy) thioacetimidate) is a kind of oxime carbamate insecticide. It is considered to be extremely toxic to nontarget organism. To date, no pure culture or consortium has been reported to have the ability to degrade methomyl completely. In this study, a methomyl-degrading enrichment E1 was obtained by using the sludge from the wastewater-treating system of a pesticide manufacturer as the original inoculant. Two bacterial strains named MDW-2 and MDW-3 were isolated from this enrichment, and they were preliminarily identified as Aminobacter sp. and Afipia sp. respectively. Strains MDW-2 and MDW-3 could coexist and degrade 50 mg l^-1 methomyl completely within 3 days by the cooperative metabolism. Methomyl was first converted to methomyl oxime and methylcarbamic acid by strain MDW-2, and the latter could be used as the carbon source for the growth of strain MDW-2. But methomyl oxime could not be sequentially degraded by strain MDW-2. However, it could be degraded and used as the carbon source by strain MDW-3.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study presents a bacterial combination of Aminobacter sp. MDW-2 and Afipia sp. MDW-3, which could degrade methomyl completely by biochemical cooperation. This study also proposes the biodegradation pathway of methomyl for the first time and highlights the application potential of a bacterial combination in the remediation of methomyl-contaminated environments.

Abstract P4-01-02: Diagnostic value of breast specific gamma imaging for breast cancer

In this study, 422 female patients who presented with clinical indications and underwent ultrasound (US), mammography (MMG), and breast specific gamma imaging (BSGI) before surgery during the period from July 2013 to June 2015 were retrospectively reviewed. Twenty-two of the patients had no pathological report available and were excluded. These patients who presented with clinical indications underwent both ultrasound and mammographic examinations initially. If both US and MMG were positive, the patient was recommended for a BSGI examination for pre-surgical planning. A BSGI examination was also recommended for patients with negative or indeterminate mammographic findings.

The diagnostic results were compared with histological examination and the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for each modality were determined. Combinations of either two or three of the diagnostic results were also reviewed and the corresponding diagnostic indicators calculated. For these combinations, a positive indication on one of the two (or three) diagnostic tests were interpreted as a positive result. The sensitivity of US, MMG, BSGI, the combination of US and MMG, US and BSGI, MMG and BSGI, and the combination of all three together in the diagnosis of breast carcinoma were determined for the 400 patients included in the study and are listed in Table 1, column 1. The specificity, PPV, and NPV for each of these modalities and combinations of modalities were also determined and are shown Table 1, column 2-4.

Table 1 SensitivitySpecificityPPVNPVUS61.389.289.759.8MMG67.594.394.765.2BSGI83.187.991.477.1US & MMG86.884.789.880.6US & BSGI91.382.889.186.1MMG & BSGI92.283.489.585.6US & MMG & BSGI97.579.087.895.4

The population was comprised of 243 patients with 245 malignant lesions and 157 patients with 189 benign lesions. The malignant lesions were primarily infiltrating ductal carcinoma (76%) and ductal carcinoma in situ (14%), with the remaining lesions (10%) being invasive lobular carcinoma, Paget's disease and mixed carcinomas. The benign lesions were primarily fibroadenoma (39%), adenosis (40%) and papilloma (10%), with the remaining lesions (11%) being duct ectasia, inflammation or phyllodes. There were 79 false negative cases by MMG, however, when ultrasound and BSGI were combined, 73 out of 79 were accurately identified. Additionally, there were nine, seventeen and eighteen Ductal Carcinoma in situ (DCIS) misdiagnosed by BSGI, MMG, and ultrasound respectively, but through joint imaging of BSGI+MMG+US; 33 out of 35 were accurately judged.

BSGI is a useful adjunct modality for the diagnosis of breast carcinoma. It is also extremely useful for diagnosis of non-calcified DCIS, and circumvents limitations of mammography in identifying malignant lesion in dense breast. Moreover, it is helpful for improving the diagnosis accuracy of breast carcinoma when BSGI is combined together with MMG and US.

Citation Format: Mallik DK, Zhang H, Shi H, Tan H, Shen L, Hu G, Hu H, Sejdinaj F, Pang Y, Zhu W, Yang W. Diagnostic value of breast specific gamma imaging for breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-01-02.

Sleep duration and quality, and risk of gestational diabetes mellitus in pregnant Chinese women

AIMS

To examine the association between sleep disturbances during pregnancy and risk of gestational diabetes mellitus.

METHODS

From 2010 to 2012, 12 506 women in Tianjin, China, were screened using a 50-g 1-h glucose challenge test at 24-28 weeks' gestation. Those with glucose challenge test values of ≥ 7.8 mmol/l were invited to further undergo a 75-g 2-h oral glucose tolerance test. Gestational diabetes was determined according to the International Association of Diabetes and Pregnancy Study Group's definition. Self-reported sleep duration and sleep quality during pregnancy was documented using a modified questionnaire. Logistic regression was used to obtain odds ratios and 95% CIs.

RESULTS

A total of 919 women (7.3%) had gestational diabetes. Sleep duration was found to have an approximate J-shaped association with gestational diabetes risk after adjusting for covariates. Compared with a sleep duration of 7-9 h/day (43% of 12 506 women), the adjusted odds ratios for sleep duration of ≥ 9 h/day (55%) and < 7 h/day (2%) for gestational diabetes were 1.21 (95% CI 1.03-1.42) and 1.36 (95% CI 0.87-2.14), respectively. Compared with good sleep quality (37.9% of 12 506 women), the adjusted odds ratios of moderate (59.9%) and poor sleep quality (2.2%) for gestational diabetes were 1.19 (95% CI 1.01-1.41) and 1.61 (95% CI 1.04-2.50), respectively.

CONCLUSION

In pregnant Chinese women, poor sleep quality, and shorter and longer duration of sleep during pregnancy were independently associated with an increased risk of gestational diabetes.

In vivo effects of high dietary copper levels on hepatocellular mitochondrial respiration and electron transport chain enzymes in broilers

The diet of broiler chickens supplemented with increasing concentrations of copper (Cu) was assessed for the effect of Cu on liver mitochondrial function. A total of 160, 1-d-old Cobb 500 broilers (Gallus domesticus) were randomly assigned in equal numbers into 4 groups, which differed in the concentration of copper supplements in the diet; 11 (control), 110, 220 and 330 mg of Cu/kg dry matter. Liver mitochondrial function was recorded at 12, 24, 36, 48 and 60 d of age. Supplementation with 110 mg Cu/kg dry matter enhanced mitochondrial function and activities of complexes I-V, and this was significant at 36 d of age compared with the other diets (P < 0.05). Supplementation with 220 mg Cu/kg dry matter and 330 mg Cu/kg dry matter enhanced mitochondrial function and activities of complexes I-V at 12, 24 and 36 d of age, but displayed reduced function (P < 0.05) at 48 and 60 d of age except in complex IV (P > 0.05). Mitochondrial hydrogen peroxide (H2O2) production was also increased (P < 0.05) with an increase of copper supplementation in the diet. The results indicate that appropriate dietary copper supplements are sufficient for improving mitochondrial function and activities of the respiratory complexes. Higher concentrations of copper, on the other hand, lead to copper toxicity by affecting certain respiratory complexes.

The microRNA-182-PDK4 axis regulates lung tumorigenesis by modulating pyruvate dehydrogenase and lipogenesis

Reprogrammed metabolism is one of the hallmarks of cancer. The dysregulation of glycolysis in cancer has been heavily studied. However, it remains largely unclear how other metabolic processes are regulated in cancer cells. Here we show that microRNA-182 (miR-182) suppresses pyruvate dehydrogenase (PDH) kinase 4 (PDK4) and promotes lung tumorigenesis. miR-182 is dysregulated and inversely correlated with PDK4 in human lung adenocarcinomas. The miR-182-PDK4 axis regulates lung cancer cell growth by modulating the activity of PDH, the gatekeeping enzyme of pyruvate flux into acetyl-CoA, and subsequently de novo lipogenesis of cancer cells. Suppression of lipogenesis by silencing ATP citrate lyase (ACLY) and fatty acid synthase (FASN) or by chemical inhibitors diminishes the effects of miR-182-PDK4 in tumor growth. Alteration of de novo lipogenesis also affects reactive oxygen species (ROS) production and the downstream JNK signaling pathway. Hence, our work suggests that the miR-182-PDK4 axis is a crucial regulator of cancer cell metabolism and a potential target for antitumor therapy.

Dorsal open reduction with pedicle screw rod internal fixation for lower cervical spine dislocation: A retrospective analysis of 12 cases

BACKGROUND

Lower cervical spine dislocation remains a surgical challenge.

METHODS

Twelve patients with lower cervical dislocation due to articular process injury underwent dorsal open reduction and manual pedicle screw rod fixation. Patients with cervical spinal cord injury received simultaneous open door expansive laminoplasty. Neurological function was evaluated using ASIA Impairment Scale 12.

RESULTS

Median time from injury to operation was 10 days (range, 5 to 52 days). Anatomic reduction was achieved in all patients. In nine patients with cervical spinal cord injury, 55.5% (5/9) showed improvement in ASIA grade following surgery. Unilateral numbness of the superior radicular area in one patient resolved 2 weeks post-surgery and two cases (11.1%, 2/9) had postoperative leakage of the cerebrospinal fluid, which resolved in 11 days and 13 days, respectively.

CONCLUSION

Dorsal open reduction and manual pedicle screw rod fixation is safe and effective for lower cervical spine dislocation due to articular process injury.

The role of 18F-FDG PET/CT in the management of patients with secondary haemophagocytic lymphohistiocytosis

AIM

To investigate the ability of combined 2-[¹⁸F]-fluoro-2-deoxy-d-glucose (¹⁸F-FDG) positron-emission tomography (PET)/computed tomography (CT) to determine potential causes of secondary haemophagocytic lymphohistiocytosis (sHLH) and to predict prognosis.

MATERIAL AND METHODS

Forty-three patients (male/female 20/23, median age 48.5 years), who were diagnosed with sHLH and underwent FDG-PET/CT before treatment, were retrospectively reviewed. The clinical characteristics were compared to identify the predictors of high-yield FDG-PET/CT. Univariate and multivariate analyses were conducted to identify factors associated with survival. Statistical analysis was performed using SPSS version 19.0.

RESULTS

PET results were helpful in 65.1% (28/43), whilst non-contributory in 34.9% (15/43) of patients with regard to the final diagnosis. Lymphoma was the most common (25/43) reason for sHLH, and patients with focal FDG uptake were more likely to be diagnosed with underlying diseases. C-reactive protein (CRP) was found to be a good indicator for the usefulness of PET/CT in HLH patients. Multivariate analysis showed that therapy regimen (hazard ratio [HR]=4.99, p=0.026), fibrinogen (FBG) <1.5 g/l (HR=3.87, p=0.049) and spleen:mediastinum ratio (SP/M) (HR=7.44, p=0.006) were independent prognostic factors for survival.

CONCLUSION

FDG-PET/CT could be a useful technique for detecting underlying diseases causing sHLH. CRP was a useful predictor of FDG-PET/CT effectiveness. Therapy regimen, FBG level, and SP/M were independent prognostic factors for HLH survival.

Mechanism underlying the bio-effects of an electromagnetic field based on the Huang-Ferrell model

To understand the beneficial and harmful bio-effects of extremely low frequency electromagnetic fields, we studied the MAPK/ERK signaling pathway based on the Huang-Ferrell model. The sensitivity analysis method was used to study the influence of the model parameters on the activity of ERK, and to further investigate the key biochemical reactions and proteins. The results of the simulation show that an increase in the reaction rate of MAPK/ERK kinase had little effect on ERK activation and the steady-state molecular number. However, a decrease in the reaction rate of MAPK/ERK kinase significantly affected the trigger time of ERK activation and decreased the steady-state molecular number. Together with the biological significance of ERK activity, our findings indicate that the effects of electromagnetic fields are a result of the decrease in the reaction rate of MAPK/ERK kinase, which eventually determines whether these effects cause physical damage or are beneficial in treatment.

Comparison of the heart failure risk stratification performance of the CKD-EPI equation and the MDRD equation for estimated glomerular filtration rate in patients with Type 2 diabetes

AIMS

To investigate the risk prediction and the risk stratification performances of the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation and the Modification of Diet in Renal Disease (MDRD) equation for estimated glomerular filtration rate (eGFRCKD - EPI vs. eGFRMDRD ) on heart failure in patients with Type 2 diabetes.

METHODS

The study cohort included 12 258 White and 16 886 African American low-income patients with Type 2 diabetes who were 30-90 years old at baseline. Heart failure risk according to different eGFRCKD - EPI and eGFRMDRD categories was prospectively assessed.

RESULTS

During a mean follow-up of 6.5 years, 5043 incident heart failure cases were identified. Multivariable-adjusted hazard ratios (HRs) of heart failure associated with the eGFRCKD - EPI categories [≥ 90 (reference group), 75-89, 60-74, 30-59 and < 30 ml/min/1.73 m(2) ] were 1.00, 1.11, 1.31, 1.75 and 2.93 (Ptrend < 0.001) for African American patients, and 1.00, 1.11, 1.08, 1.59 and 2.92 (Ptrend < 0.001) for White patients, respectively. The model with eGFRCKD - EPI and the other risk factors had significantly higher Harrell's C than the model with eGFRMDRD and other risk factors. Patients reclassified downward from eGFRMDRD 60-74 to eGFRCKD - EPI 30-59 and from eGFRMDRD 30-59 to eGFRCKD - EPI < 30 ml/min/1.73 m(2) showed higher heart failure risk than those who were not reclassified.

CONCLUSIONS

Impaired kidney function (i.e. GFR < 60 ml/min/1.73 m(2) ), and even mildly decreased GFR (60-74 ml/min/1.73 m(2) ) estimated by both equations is associated with an increased risk of heart failure. Compared with GFR estimated using the MDRD equation, GFR estimated using the CKD-EPI equation added more predictive power to the model with the other risk factors. Also, eGFRCKD - EPI provided more accurate heart failure risk stratification than eGFRMDRD .

Leptin changes differentiation fate and induces senescence in chondrogenic progenitor cells

Body weight is a component of the mechanical theory of OA (osteoarthritis) pathogenesis. Obesity was also found to be a risk factor for digital OA involving non-weight-bearing joints, which suggested that metabolism influences the occurrence and progression of OA. The metabolic origin of OA has been partially attributed to the involvement of adipokines, such as leptin, the levels of which are significantly and positively correlated with cartilage degeneration in OA patients. However, the mechanisms by which leptin-induced cartilage degeneration occurs are poorly understood. The discovery of chondrogenic progenitor cells (CPCs) opened up new opportunities for investigation. Investigating the effects of leptin on differentiation and proliferation in CPCs would increase our understanding of the roles played by leptin in the aetiology and development of OA. Here, CPCs were harvested using single-cell sorting from rat cartilage tissues to obtain mesenchymal stem-like cells, which possess clonogenicity, proliferation and stemness. High doses of leptin decreased the ability of the CPCs to migrate, inhibited their chondrogenic potential and increased their osteogenic potential, suggesting that leptin changes differentiation fates in CPCs. High doses of leptin induced cell cycle arrest and senescence in CPCs by activating the p53/p21 pathway and inhibiting the Sirt1 pathway. Inhibiting the Sirt1 pathway accelerated cartilage senescence in knockout (KO) mice. Activating the leptin pathway induced higher Ob-Rb expression and was significantly correlated with cartilage degeneration (lower levels of Coll-2) and tissue senescence (higher levels of p53/p21 and lower levels of Sirt1) in OA patients, suggesting that leptin-induced CPCs senescence contributes to the development of OA. Taken together, our results reveal new links between obesity and cartilage damage that are induced by leptin-mediated effects on cell behaviour and senescence.

Influence of Dipole Orientation on Solution Properties of Polyzwitterions

We have studied the influence of segmental dipole orientation on the solution properties of polyzwitterions using dynamic and static light scattering of poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC), n-butyl-substituted choline phosphate polymers (PMBP), and their diblock (PMPC-b-PMBP) copolymers in solutions of different salt concentration. We find that these three structures exhibit dramatically different aggregation behaviors. For the conditions in our study, PMPC is a swollen excluded-volume chain without significant presence of dipolar correlations as evident from the lack of sensitivity to the ionic strength of the solution. In contrast, PMBP self-assembles into finite-sized structures in solution, which are stabilized by electrostatic dipole-dipole interactions. Evidence of these interactions is also present in the diblock polymer, PMPB-b-PMPC, which self-assembles into two distinct, stable aggregates in addition to unaggregated chains. These results contribute to the breadth of understanding of polyzwitterions in solution and provide a platform for future simulation and experimental explorations.

Changes in astrocyte functional markers and β-amyloid metabolism-related proteins in the early stages of hypercholesterolemia

Cholesterol is an essential substance for maintaining normal structure and function of the brain. But unfortunately, a long-term high-cholesterol diet can lead to a variety of pathological changes of the brain such as β-amyloid (Aβ) accumulation, Tau hyperphosphorylation, reactive gliosis, neuroinflammation, neuronal death and synaptic degeneration. These pathological changes have complex internal relations with one other, causing memory impairment and participating in the pathogenesis of Alzheimer's disease (AD). However, early hypercholesterolemia-induced events that lead to brain deterioration are not clear. To address this, 6-month-old female mice were fed a 3% cholesterol diet for 8weeks, followed by behavioral, biochemical and neuropathological analyses. The high-cholesterol-fed mice did not show neuronal and synaptic impairment or cognitive deficits compared with mice given a normal diet, but astrocytes were mildly activated with increased expression of functional markers including apolipoprotein E and aquaporin 4 in the hippocampus. Hippocampal interleukin-1β expression slightly increased, but interleukin-6 (IL-6) and tumor necrosis factor-α did not change significantly compared with those in the control group. Levels of Aβ, and its precursor protein, were unaffected, but levels of presenilin 1 and insulin-degrading enzyme (IDE), that initiate Aβ generation and degradation, respectively, increased in the hippocampus of the model mice. In addition, Tau phosphorylation levels were not different between the control and model groups. These results suggest that changes in astrocyte functional markers and Aβ metabolism proteins, which contribute to maintaining brain cholesterol and Aβ homeostasis, are early events in the process of hypercholesterolemia-related neuropathological changes.

Association between body mass index and body fat in 9-11-year-old children from countries spanning a range of human development

The purpose was to assess associations between body mass index (BMI) and body fat in a multinational sample of 9-11-year-old children. The sample included 7265 children from countries ranging in human development. Total body fat (TBF) and percentage body fat (PBF) were measured with a Tanita SC-240 scale and BMI z-scores (BMIz) and percentiles were computed using reference data from the World Health Organization and the U.S. Centers for Disease Control and Prevention, respectively. Mean PBF at BMIz values of -1, 0 and +1 were estimated using multilevel models. Correlations between BMI and TBF were >0.90 in all countries, and correlations between BMI and PBF ranged from 0.76 to 0.96. Boys from India had higher PBF than boys from several other countries at all levels of BMIz. Kenyan girls had lower levels of PBF than girls from several other countries at all levels of BMIz. Boys and girls from Colombia had higher values of PBF at BMIz=-1, whereas Colombian boys at BMIz 0 and +1 also had higher values of PBF than boys in other countries. Our results show a consistently high correlation between BMI and adiposity in children from countries representing a wide range of human development.

Associations between sleep patterns and lifestyle behaviors in children: an international comparison

OBJECTIVES

Although evidence is accumulating on the importance of a good night's sleep for healthy eating and activity behaviors, existing research has mainly been conducted in high-income, developed countries with limited sociocultural variability. This study is the first to examine the associations between sleep patterns and lifestyle behaviors in children from 12 countries in five major geographic regions of the world.

METHODS

This observational, multinational cross-sectional study included 5777 children aged 9-11 years from sites in Australia, Brazil, Canada, China, Colombia, Finland, India, Kenya, Portugal, South Africa, the United Kingdom and the United States. Nocturnal sleep duration (hours per night), sleep efficiency (%) and bedtime (h:min) were monitored over 7 consecutive days using an accelerometer. Lifestyle behaviors included moderate-to-vigorous physical activity (MVPA), total sedentary time (SED), self-reported screen time (ST) and healthy/unhealthy diet patterns (HDP/UDP). Multilevel modeling analyses were used to account for the hierarchical nature of the data.

RESULTS

Overall, participants averaged 8.8 (s.d. 0.9) hours of sleep with 96.2% (s.d. 1.4) sleep efficiency and a mean bedtime of 2218 hours. After adjustment for age, sex, highest parental education and BMI z-score, results showed that (i) sleep duration was negatively associated with MVPA, SED and UDP score; (ii) sleep efficiency was negatively associated with MVPA and UDP score, and positively associated with SED; and (iii) later bedtime was positively associated with SED, ST and UDP score, and negatively associated with MVPA and HDP score. Results using categories of sleep patterns were consistent with the linear associations. Results also revealed that associations between sleep patterns and MVPA, SED and ST were significantly different between study sites, with stronger associations in high-income countries compared with low/middle-income countries.

CONCLUSIONS

Sleep characteristics are important correlates of lifestyle behaviors in children. Differences between countries suggest that interventions aimed at improving sleep and lifestyle behaviors should be culturally adapted.

Nocturnal sleep-related variables from 24-h free-living waist-worn accelerometry: International Study of Childhood Obesity, Lifestyle and the Environment

OBJECTIVES

We describe the process of identifying and defining nocturnal sleep-related variables (for example, movement/non-movement indicators of sleep efficiency, waking episodes, midpoint and so on) using the unique 24-h waist-worn free-living accelerometer data collected in the International Study of Childhood Obesity, Lifestyle and the Environment (ISCOLE).

METHODS

Seven consecutive days of 24-h waist-worn accelerometer (GT3X+, ActiGraph LLC) data were collected from over 500 children at each site. An expert subgroup of the research team with accelerometry expertize, frontline data collectors and data managers met on several occasions to categorize and operationally define nocturnal accelerometer signal data patterns. The iterative process was informed by the raw data drawn from a sub set of the US data, and culminated in a refined and replicable delineated definition for each identified nocturnal sleep-related variable. Ultimately based on 6318 participants from all 12 ISCOLE sites with valid total sleep episode time (TSET), we report average clock times for nocturnal sleep onset, offset and midpoint in addition to sleep period time, TSET and restful sleep efficiency (among other derived variables).

RESULTS

Nocturnal sleep onset occurred at 2218 hours and nocturnal sleep offset at 0707 hours. The mean midpoint was 0243 hours. The sleep period time of 529.6 min (8.8 h) was typically accumulated in a single episode, making the average TSET very similar in duration (529.0 min). The mean restful sleep efficiency ranged from 86.8% (based on absolute non-movement of 0 counts per minute) to 96.0% (based on relative non-movement of <100 counts per minute).

CONCLUSIONS

These variables extend the potential of field-based 24-h waist-worn accelerometry to distinguish and categorize the underlying robust patterns of movement/non-movement signals conveying magnitude, duration, frequency and periodicity during the nocturnal sleep period.

Associations between breakfast frequency and adiposity indicators in children from 12 countries

OBJECTIVES

Reports of inverse associations between breakfast frequency and indices of obesity are predominantly based on samples of children from high-income countries with limited socioeconomic diversity. Using data from the International Study of Childhood Obesity, Lifestyle and the Environment (ISCOLE), the present study examined associations between breakfast frequency and adiposity in a sample of 9-11-year-old children from 12 countries representing a wide range of geographic and socio-cultural variability.

METHODS

Multilevel statistical models were used to examine associations between breakfast frequency (independent variable) and adiposity indicators (dependent variables: body mass index (BMI) z-score and body fat percentage (BF%)), adjusting for age, sex, and parental education in 6941 children from 12 ISCOLE study sites. Associations were also adjusted for moderate-to-vigorous physical activity, healthy and unhealthy dietary patterns and sleep time in a sub-sample (n=5710). Where interactions with site were significant, results were stratified by site.

RESULTS

Adjusted mean BMI z-score and BF% for frequent breakfast consumers were 0.45 and 20.5%, respectively. Frequent breakfast consumption was associated with lower BMI z-scores compared with occasional (P<0.0001, 95% confidence intervals (CI): 0.10-0.29) and rare (P<0.0001, 95% CI: 0.18-0.46) consumption, as well as lower BF% compared with occasional (P<0.0001, 95% CI: 0.86-1.99) and rare (P<0.0001, 95% CI: 1.07-2.76). Associations with BMI z-score varied by site (breakfast by site interaction; P=0.033): associations were non-significant in three sites (Australia, Finland and Kenya), and occasional (not rare) consumption was associated with higher BMI z-scores compared with frequent consumption in three sites (Canada, Portugal and South Africa). Sub-sample analyses adjusting for additional covariates showed similar associations between breakfast and adiposity indicators, but lacked site interactions.

CONCLUSIONS

In a multinational sample of children, more frequent breakfast consumption was associated with lower BMI z-scores and BF% compared with occasional and rare consumption. Associations were not consistent across all 12 countries. Further research is required to understand global differences in the observed associations.

Active school transport and weekday physical activity in 9-11-year-old children from 12 countries

OBJECTIVES

Active school transport (AST) may increase the time that children spend in physical activity (PA). This study examined relationships between AST and weekday moderate-to-vigorous physical activity (MVPA), light physical activity (LPA), sedentary time (SED) and total activity during naturally organized time periods (daily, before school, during school and after school) in a sample of children from 12 countries.

METHODS

The sample included 6224 children aged 9-11 years. PA and sedentary time were objectively measured using Actigraph accelerometers. AST was self-reported by participants. Multilevel generalized linear and logistic regression statistical models were used to determine associations between PA, SED and AST across and within study sites.

RESULTS

After adjustment for age, highest parental educational attainment, BMI z-score and accelerometer wear time, children who engaged in AST accumulated significantly more weekday MVPA during all studied time periods and significantly less time in LPA before school compared with children who used motorized transport to school. AST was unrelated to time spent in sedentary behaviors. Across all study sites, AST was associated with 6.0 min (95% confidence interval (CI): 4.7-7.3; P<0.0001) more of weekday MVPA; however, there was some evidence that this differed across study sites (P for interaction=0.06). Significant positive associations were identified within 7 of 12 study sites, with differences ranging from 4.6 min (95% CI: 0.3-8.9; P=0.04, in Canada) to 10.2 min (95% CI: 5.9-14.4; P<0.0001, in Brazil) more of daily MVPA among children who engaged in AST compared with motorized transport.

CONCLUSIONS

The present study demonstrated that AST was associated with children spending more time engaged in MVPA throughout the day and less time in LPA before school. AST represents a good behavioral target to increase levels of PA in children.

Relationships between active school transport and adiposity indicators in school-age children from low-, middle- and high-income countries

OBJECTIVES

Within the global context of the nutrition and physical activity transition it is important to determine the relationship between adiposity and active school transport (AST) across different environmental and socio-cultural settings. The present study assessed the association between adiposity (that is, body mass index z-score (BMIz), obesity, percentage body fat (PBF), waist circumference) and AST in 12 country sites, in the International Study of Childhood Obesity, Lifestyle and the Environment (ISCOLE).

METHODS

The analytical sample included 6797 children aged 9-11 years. Adiposity indicators included, BMIz calculated using reference data from the World Health Organization, obesity (BMIz ⩾+2 s.d.), PBF measured using bioelectrical impedance and waist circumference. School travel mode was assessed by questionnaire and categorized as active travel versus motorized travel. Multilevel linear and non-linear models were used to estimate the magnitude of the associations between adiposity indicators and AST by country site and sex.

RESULTS

After adjusting for age, sex, parental education and motorized vehicle availability, children who reported AST were less likely to be obese (odds ratio=0.72, 95% confidence interval (0.60-0.87), P<0.001) and had a lower BMIz (-0.09, s.e.m.=0.04, P=0.013), PBF (least square means (LSM) 20.57 versus 21.23% difference -0.66, s.e.m.=0.22, P=0.002) and waist circumference (LSM 63.73 cm versus 64.63 cm difference -0.90, s.e.m.=0.26, P=0.001) compared with those who reported motorized travel. Overall, associations between obesity and AST did not differ by country (P=0.279) or by sex (P=0.571).

CONCLUSIONS

AST was associated with lower measures of adiposity in this multinational sample of children. Such findings could inform global efforts to prevent obesity among school-age children.

Birth weight and childhood obesity: a 12-country study

OBJECTIVES

Few studies have investigated the association between the full range of birth weight and the risk of childhood obesity in high-, middle- and low-income countries. The aim of the present study is to assess the association between different levels of birth weight and the risk of obesity among children aged 9-11 years in 12 countries.

METHODS

A multinational, cross-sectional study of 5141 children aged 9-11 years was conducted in 12 countries. Height and weight were obtained using standardized methods. Time spent in moderate-to-vigorous physical activity (MVPA), sedentary and sleeping were objectively measured using 24-h, waist-worn accelerometer (Actigraph GT3X+) monitored for 7 days. Birth weight and other factors (regions, parental education, maternal history of gestational diabetes, children age, gender, breast feeding, gestational age, unhealthy diet scores and healthy diet scores) were collected by parental and children's questionnaires. Multilevel modeling was used to account for the nested nature of the data.

RESULTS

The overall prevalence of obesity (BMI z-score>+2 s.d.) was 15.4% for boys and 10.0% for girls. There was a positive association between birth weight and BMI z-scores. The multivariable-adjusted odds ratios (ORs) of childhood obesity were significantly higher among children whose birth weights were 3500-3999 g (OR 1.45; 95% confidence interval (CI): 1.10-1.92), and >4000 g (OR 2.08; 95% CI: 1.47-2.93), compared with the reference group (2500-2999 g). The positive association between birth weight and the odds of childhood obesity was seen in girls, whereas a U-shaped association appeared in boys.

CONCLUSIONS

High levels of birth weight, defined as birth weight ⩾3500 g, were associated with increased odds of obesity among 9-11-year-old children in 12 countries. However, sex differences in the association between birth weight and the risk of obesity need to be considered when planning interventions to reduce childhood obesity.