The impact of COVID-19 on surgical training: a systematic review.

BACKGROUND: Coronavirus disease (COVID-19) has caused global disruption to health care. Non-urgent elective surgical cases have been cancelled, outpatient clinics have reduced and there has been a reduction in the number of patients presenting as an emergency. These factors will drastically affect the training opportunities of surgical trainees. The aim of this systematic review is to describe the impact of COVID-19 on surgical training globally. METHODS: The review was performed in line with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and registered with the Open Science Framework (OSF). Medline, EMBASE, PubMed and the Cochrane Central Register of Controlled Trials were searched. RESULTS: The searches identified 499 articles, 29 of which were included in the review. This contained data from more than 20 countries with 5260 trainees and 339 programme directors. Redeployment to non-surgical roles varied across studies from 6% to 35.1%. According to all of the studies, operative experience has been reduced. Knowledge learning had been switched to online platforms across 17 of the studies and 7 reported trainees had increased time to devote to educational/academic activities. All of the studies reporting on mental health report negative associations with increased stress, ranging from 54.9% to 91.6% of trainees. CONCLUSIONS: The impact of COVID-19 on surgical trainees has been experienced globally and across all specialities. Negative effects are not limited to operative and clinical experience, but also the mental health and wellbeing of trainees. Delivery of surgical training will need to move away from traditional models of learning to ensure trainees are competent and well supported.

Mothers' perceptions of child weight status and the subsequent weight gain of their children: a population-based longitudinal study.

BACKGROUND: There is a plethora of cross-sectional work on maternal perceptions of child weight status showing that mothers typically do not classify their overweight child as being overweight according to commonly used clinical criteria. Awareness of overweight in their child is regarded as an important prerequisite for mothers to initiate appropriate action. The gap in the literature is determining whether, if mothers do classify their overweight child's weight status correctly, this is associated with a positive outcome for the child's body mass index (BMI) at a later stage. OBJECTIVE: To explore longitudinal perceptions of child weight status from mothers of a contemporary population-based birth cohort (Gateshead Millennium Study) and relationships of these perceptions with future child weight gain. METHODS: Data collected in the same cohort at 7, 12 and 15 years of age: mothers' responses to two items concerning their child's body size; child's and mother's BMI; pubertal maturation; demographic information. RESULTS: Mothers' perceptions of whether their child was overweight did not change markedly over time. Child BMI was the only significant predictor of mothers' classification of overweight status, and it was only at the extreme end of the overweight range and in the obese range that mothers reliably described their child as overweight. Even when mothers did appropriately classify their child as overweight at an earlier stage, this was not related to relatively lower child BMI a few years later. CONCLUSIONS: Mothers tend to classify their child as overweight in only more extreme cases. It is an important finding that no beneficial impact was shown on later child BMI in overweight children whose mothers classified their child's weight status as overweight at an earlier stage.

Longitudinal study of the associations between change in sedentary behavior and change in adiposity during childhood and adolescence: Gateshead Millennium Study.

BACKGROUND: Sedentary time (ST) has been reported to have a range of negative health effects in adults, however, the evidence for such effects among children and adolescents is sparse. The primary aim of the study was to examine associations between changes in sedentary behavior (time and fragmentation) and changes in adiposity across childhood and adolescence. METHODS: Participants were recruited as part of the Gateshead Millennium Study. Measures were taken at age 7 (n=502), 9 (n=506), 12 (n=420) and 15 years (n=306). Participants wore an ActiGraph GT1M and accelerometer epochs were 'sedentary' when recorded counts were ⩽25 counts per 15 s. ST was calculated and fragmentation (SF) was assessed by calculating the number of sedentary bouts per sedentary hour. Associations of changes in ST and SF with changes in adiposity (body mass index (BMI), and fat mass index (FMI)) were examined using bivariate linear spline models. RESULTS: Increasing ST by 1% per year was associated with an increase in BMI of 0.08 kg m-2 per year (95% CI: 0.06-0.10; P<0.001) and FMI of 0.15 kg m-2 per year (0.11-0.19; P<0.001). Change in SF was associated with BMI and FMI (P<0.001). An increase of 1 bout per sedentary hour per year (that is, sedentary time becoming more fragmented) was associated with an increase in BMI of 0.07 kg m-2 per year (0.06-0.09; P<0.001) and an increase in FMI of 0.14 kg m-2 per year (0.10-0.18; P<0.001) over the 8 years period. However, an increase in SF between 9-12 years was associated with a 0.09 kg m-2 per year decrease in BMI (-0.18-0.00; P=0.046) and 0.11 kg m-2 per year decrease in FMI (-0.22-0.00; P=0.049). CONCLUSIONS: Increased ST and increased SF from 7-15 years were associated with increased adiposity. This is the first study to show age-specific associations between change in objectively measured sedentary behavior and adiposity after adjustment of moderate-to-vigorous-intensity physical activity in children and adolescents. The study suggests that, targeting sedentary behavior for obesity prevention may be most effective during periods in which we see large increases in ST.

Risk factors for overweight and overfatness in rural South African children and adolescents.

BACKGROUND: To determine risk factors for overweight/overfatness in children and adolescents from rural KwaZulu-Natal, South Africa. METHODS: Anthropometric data were collected from a cross-sectional sample (n = 1519, ages 7, 11 and 15 years) and linked to demographic information (n = 1310 and n = 1317 in overweight and overfat analyses, respectively). Candidate risk factors for overweight/overfatness were identified and tested for associations with overweight (BMI-for-age >+1SD, WHO reference) and overfatness (>85th centile body fatness, McCarthy reference) as outcomes. Associations were examined using simple tests of proportions (χ(2)/Mann-Whitney U tests) and multivariable logistic regression. RESULTS: Sex was a consistent variable across both analyses; girls at significantly increased risk of overweight and overfatness (overweight: n = 180, 73.9 and 26.1% females and males, respectively (P < 0.0001); overfat: n = 187, 72.7 and 27.3% females and males, respectively (P < 0.0001)). In regression analyses, sex and age (defined by school grade) were consistent variables, with boys at lower risk of overweight (adjusted odds ratio (AOR) 0.40 (confidence interval (CI) -0.28-0.57)) and risk of overweight increasing with age (AOR 0.65 (CI- 0.44-0.96), 0.50 (CI-0.33-0.75) and 1.00 for school grades 1, 5 and 9, respectively). Results were similar for overfatness. CONCLUSIONS: This study suggests that pre-adolescent/adolescent females may be the most appropriate targets of future interventions aimed at preventing obesity in rural South Africa.

Impact of eating and drinking on body composition measurements by bioelectrical impedance.

BACKGROUND: Bioelectrical impedance analysis would be a more practical tool to measure body composition in clinical settings, dietetic practice and epidemiological studies if patients/subjects did not have to fast before measurements. The present study assessed whether the ingestion of food or drink had any biologically significant effect on bioimpedance measurements and body composition by the foot-to-foot method. METHODS: Fifty-five healthy adults [30 males and 25 females; mean (SD) age 27.7 (7.1) years; mean (SD)body mass index 24 (3.8) kg m(-2)] were randomly assigned to a 2-day food trial (high-fat meal or high-carbohydrate meal) or a 2-day drink trial (water or high electrolyte drink). Body composition measurements were carried out in the fasting state, immediately after meal consumption and every 30 min for 2 h by the foot-to-foot single frequency bioimpedance technique. RESULTS: Bioimpedance increased significantly after the ingestion of food and fluid, although the changes were small. The electrolyte drink, high-fat and high-carbohydrate meals significantly increased the percentage body fat and fat mass. In all cases, the median percentage changes from baseline were approximately 1% in body fat percentage units. CONCLUSIONS: Although there were statistically significant changes in body composition estimates after food or drink consumption, these were small and within the imprecision of the impedance technique, and so are unlikely to be of clinical significance. The present study suggests that impedance measures of body fatness in clinical settings do not require strict adherence to fasting, and this should increase the opportunities for clinical application.

Obesity impairs academic attainment in adolescence: findings from ALSPAC, a UK cohort.

OBJECTIVE: While being overweight or obese in adolescence may have detrimental effects on academic attainment, the evidence base is limited by reliance on cross-sectional studies with small sample sizes, failure to take account of confounders and lack of consideration of potential mediators. The present study aimed to address these limitations and examine longitudinal associations between obesity in adolescence and academic attainment. DESIGN: Associations between weight status at 11 years old and academic attainment assessed by national tests at 11, 13 and 16 years were examined in the Avon Longitudinal Study of Parents and Children. Healthy weight was defined as body mass index (BMI) Z-score <1.04; overweight as BMI Z-score 1.04-1.63; obesity as BMI Z-score ⩾1.64. PARTICIPANTS: Data from 5966 participants with objectively measured weight status were examined: 71.4% were healthy weight (1935 males; 2325 females), 13.3% overweight (372 males; 420 females) and 15.3% obese (448 males; 466 females). RESULTS: Girls obese at 11 years had lower academic attainment at 11, 13 and 16 years compared with those of a healthy weight, even after controlling for a wide range of confounders. Associations between obesity and academic attainment were less clear in boys. The potential mediating effects of depressive symptoms, intelligence quotient (IQ) and age of menarche in girls were explored, but when confounders were included, there was no strong evidence for mediation. CONCLUSIONS: For girls, obesity in adolescence has a detrimental impact on academic attainment 5 years later. Mental health, IQ and age of menarche did not mediate this relationship, suggesting that further work is required to understand the underlying mechanisms. Parents, education and public health policy makers should consider the wide reaching detrimental impact of obesity on educational outcomes in this age group.

Prevalence of being underweight and overweight and obesity at diagnosis in UK patients with childhood acute lymphoblastic leukaemia 1985-2002.

BACKGROUND: Being underweight or overweight and obesity at diagnosis may all worsen prognosis in childhood acute lymphoblastic leukaemia (ALL), although no studies have estimated the prevalence of an unhealthy weight status at diagnosis in large representative samples using contemporary definitions of weight status based on body mass index (BMI) for age. METHODS: The present study comprised a retrospective study that aimed to estimate prevalence of being underweight and overweight and obesity at diagnosis for patients with childhood ALL on three successive UK treatment trials: UKALL X (1985-1990; n = 1033), UKALL XI (1990-1997; n = 2031), UKALL 97/99 (1997-2002; n = 898).The BMI for age was used to define weight status with both UK 1990 BMI for age reference data and the Cole-International Obesity Task Force (IOTF) definitions. RESULTS: The prevalence of being underweight was 6% in the most recent trial for which data were available. The prevalence of being overweight and obesity was 35% in the most recent trial when expressed using Cole-IOTF definitions and 41% when expressed relative to UK 1990 reference data. CONCLUSIONS: Even with highly conservative estimates, >40% of all UK patients with ALL were underweight, overweight or obese at diagnosis in the most recent trial for which UK data are available (UKALL 97/99, 1997-2002).

Associations between objectively measured physical activity and academic attainment in adolescents from a UK cohort.

BACKGROUND: To test for cross-sectional (at age 11) and longitudinal associations between objectively measured free-living physical activity (PA) and academic attainment in adolescents.Method Data from 4755 participants (45% male) with valid measurement of PA (total volume and intensity) by accelerometry at age 11 from the Avon Longitudinal Study of Parents and Children (ALSPAC) was examined. Data linkage was performed with nationally administered school assessments in English, Maths and Science at ages 11, 13 and 16. RESULTS: In unadjusted models, total volume of PA predicted decreased academic attainment. After controlling for total volume of PA, percentage of time spent in moderate-vigorous intensity PA (MVPA) predicted increased performance in English assessments in both sexes, taking into account confounding variables. In Maths at 16 years, percentage of time in MVPA predicted increased performance for males (standardised ß=0.11, 95% CI 0.00 to 0.22) and females (ß=0.08, 95% CI 0.00 to 0.16). For females the percentage of time spent in MVPA at 11 years predicted increased Science scores at 11 and 16 years (ß=0.14 (95% CI 0.03 to 0.25) and 0.14 (0.07 to 0.21), respectively). The correction for regression dilution approximately doubled the standardised ß coefficients. CONCLUSIONS: Findings suggest a long-term positive impact of MVPA on academic attainment in adolescence.

Validation of anthropometry and foot-to-foot bioelectrical resistance against a three-component model to assess total body fat in children: the IDEFICS study.

OBJECTIVE: To compare different field methods for estimating body fat mass with a reference value derived by a three-component (3C) model in pre-school and school children across Europe. DESIGN: Multicentre validation study. SUBJECTS: Seventy-eight preschool/school children aged 4-10 years from four different European countries. METHODS: A standard measurement protocol was carried out in all children by trained field workers. A 3C model was used as the reference method. The field methods included height and weight measurement, circumferences measured at four sites, skinfold measured at two-six sites and foot-to-foot bioelectrical resistance (BIA) via TANITA scales. RESULTS: With the exception of height and neck circumference, all single measurements were able to explain at least 74% of the fat-mass variance in the sample. In combination, circumference models were superior to skinfold models and height-weight models. The best predictions were given by trunk models (combining skinfold and circumference measurements) that explained 91% of the observed fat-mass variance. The optimal data-driven model for our sample includes hip circumference, triceps skinfold and total body mass minus resistance index, and explains 94% of the fat-mass variance with 2.44 kg fat mass limits of agreement. In all investigated models, prediction errors were associated with fat mass, although to a lesser degree in the investigated skinfold models, arm models and the data-driven models. CONCLUSION: When studying total body fat in childhood populations, anthropometric measurements will give biased estimations as compared to gold standard measurements. Nevertheless, our study shows that when combining circumference and skinfold measurements, estimations of fat mass can be obtained with a limit of agreement of 1.91 kg in normal weight children and of 2.94 kg in overweight or obese children.

Considerations for numerical modeling of the pulmonary circulation--a review with a focus on pulmonary hypertension.

Both in academic research and in clinical settings, virtual simulation of the cardiovascular system can be used to rapidly assess complex multivariable interactions between blood vessels, blood flow, and the heart. Moreover, metrics that can only be predicted with computational simulations (e.g., mechanical wall stress, oscillatory shear index, etc.) can be used to assess disease progression, for presurgical planning, and for interventional outcomes. Because the pulmonary vasculature is susceptible to a wide range of pathologies that directly impact and are affected by the hemodynamics (e.g., pulmonary hypertension), the ability to develop numerical models of pulmonary blood flow can be invaluable to the clinical scientist. Pulmonary hypertension is a devastating disease that can directly benefit from computational hemodynamics when used for diagnosis and basic research. In the present work, we provide a clinical overview of pulmonary hypertension with a focus on the hemodynamics, current treatments, and their limitations. Even with a rich history in computational modeling of the human circulation, hemodynamics in the pulmonary vasculature remains largely unexplored. Thus, we review the tasks involved in developing a computational model of pulmonary blood flow, namely vasculature reconstruction, meshing, and boundary conditions. We also address how inconsistencies between models can result in drastically different flow solutions and suggest avenues for future research opportunities. In its current state, the interpretation of this modeling technology can be subjective in a research environment and impractical for clinical practice. Therefore, considerations must be taken into account to make modeling reliable and reproducible in a laboratory setting and amenable to the vascular clinic. Finally, we discuss relevant existing models and how they have been used to gain insight into cardiopulmonary physiology and pathology.

Can we modulate physical activity in children?

There is concern that interventions that use physical activity to prevent obesity in children might be undermined by an 'Activitystat', which exerts an effect to maintain a low set point for physical activity. The present critique summarises evidence from systematic reviews of interventions, from empirical tests of the Activitystat hypothesis, from studies on the heritability of physical activity in childhood and the physical activity of children of and adolescents across a wide range of physical and cultural environments. This body of evidence is inconsistent with the Activitystat hypothesis in its current form, and suggests that the emphasis on physical activity in obesity prevention interventions in children should be increased, not reduced.

Long-term impact of overweight and obesity in childhood and adolescence on morbidity and premature mortality in adulthood: systematic review.

BACKGROUND AND OBJECTIVE: The last systematic review on the health consequences of child and adolescent obesity found little evidence on consequences for adult health. The present study aimed to summarize evidence on the long-term impact of child and adolescent obesity for premature mortality and physical morbidity in adulthood. METHODS: Systematic review with evidence searched from January 2002 to June 2010. Studies were included if they contained a measure of overweight and/or obesity between birth and 18 years (exposure measure) and premature mortality and physical morbidity (outcome) in adulthood. RESULTS: Five eligible studies examined associations between overweight and/or obesity, and premature mortality: 4/5 found significantly increased risk of premature mortality with child and adolescent overweight or obesity. All 11 studies with cardiometabolic morbidity as outcomes reported that overweight and obesity were associated with significantly increased risk of later cardiometabolic morbidity (diabetes, hypertension, ischaemic heart disease, and stroke) in adult life, with hazard ratios ranging from 1.1-5.1. Nine studies examined associations of child or adolescent overweight and obesity with other adult morbidity: studies of cancer morbidity were inconsistent; child and adolescent overweight and obesity were associated with significantly increased risk of later disability pension, asthma, and polycystic ovary syndrome symptoms. CONCLUSIONS: A relatively large and fairly consistent body of evidence now demonstrates that overweight and obesity in childhood and adolescence have adverse consequences on premature mortality and physical morbidity in adulthood.

Impact of methodological decisions on accelerometer outcome variables in young children.

BACKGROUND: The impact of accelerometer-related methodological decisions relating to the assessment of physical activity and sedentary time has not been conclusively determined in young children. OBJECTIVES: To determine the effects of epoch and cutoff points on the assessment of physical activity and sedentary time and to determine the accelerometer wear time required to achieve reliable accelerometer data in children. DESIGN: Children were recruited from centres at Ghent, Glasgow, Gothenburg and Zaragoza. METHODS: Physical activity was assessed for 1 week in 86 children (41 girls, 45 boys; mean age 7±2 years) by uniaxial accelerometry. The epoch was set at 15 s and reintegrated to 30 and 60 s. Time spent sedentary and in moderate and vigorous physical activity (MVPA) was assessed using a range of cutoff points. Number of days required to achieve 80% reliability was predicted using the Spearman-Brown Prophecy formula. RESULTS: The Reilly cutoff points (<1100 counts per min (CPM)) indicated less sedentary time per day when comparing 15 vs 30 s and 15 vs 60 s epochs: 570±91 vs 579±93 min and 570±91 vs 579±94 min, respectively; P<0.05. Pate cutoff points (>420 counts per 15 s) reported more MVPA time per day compared with Sirard (890 counts per 15 s) and Puyau cutoff points (>3200 counts per min) using 15 s epoch: 78 (4-197) min (median (range) vs 18 (1-80) min and 24 (1-100) min, respectively; P<0.001. Compliance with guidelines of at least 60 min MVPA was 84, 78 and 73% for Pate cutoff points using 15, 30 and 60 s epochs, respectively, but 0% for Sirard and Puyau cutoff points across epochs. The number of days required to achieve 80% reliability for CPM, sedentary and MVPA time was 7.4-8.5 days. CONCLUSION: Choice of epoch and cutoff point significantly influenced the classification of sedentary and MVPA time and observed compliance to the MVPA guidelines.

The IDEFICS validation study on field methods for assessing physical activity and body composition in children: design and data collection.

OBJECTIVE: To describe the design, measurements and fieldwork of the IDEFICS (Identification and prevention of dietary- and lifestyle-induced health effects in children and infants) physical activity and body composition validation study, and to determine the potential and limitations of the data obtained. DESIGN: Multicentre validation study. SUBJECTS: A total of 98 children from four different European countries (age: 4-10 years). METHODS: An 8-day measurement protocol was carried out in all children using a collaborative protocol. Reference methods were the doubly labelled water method for physical activity, and a three- and a four-compartment model for body composition. Investigated field methods were accelerometers, a physical activity questionnaire and various anthropometric measurements. RESULTS: For the validation of physical activity field methods, it was possible to gather data from 83 to 89 children, laying the basis for age- and sex-specific results. The validation of body composition field methods is possible in 64-80 children and allows sex-specific analyses but has only limited statistical power in the youngest age group (<6 years). The amount of activity energy expenditure (AEE) varied between centres, sexes and age groups, with boys and older children having higher estimates of AEE. After normalisation of AEE by body weight, most group-specific differences diminished, except for country-specific differences. CONCLUSION: The IDEFICS validation study will allow age- and sex-specific investigation of questions pertaining to the validity of several field methods of body composition and physical activity, using established reference methods in four different European countries. From the participant analyses it can be concluded that the compliance for the investigated field methods was higher than that for the reference methods used in this validation study.

Assessment of obesity in children and adolescents: synthesis of recent systematic reviews and clinical guidelines.

This review summarises recent systematic reviews and evidence-based guidelines that deal with the issue of how best to diagnose or define obesity in children and adolescents. A recent systematic review showed that parents typically fail to recognise obesity in their children and adolescents, and a good deal of other evidence suggests that health professionals under-diagnose obesity in children and adolescents when using informal methods based on observation. There is therefore a need for practical, objective, methods that both identify the fattest children and adolescents adequately, and identify those who are at greatest risk of the 'co-morbidities' of obesity. A large body of consistent evidence shows that a high body mass index (BMI) for age and sex identifies the fattest children adequately, with low-moderate false negative rate and a low false positive rate. Furthermore, children and adolescents at high BMI for age are at much greater risk of the co-morbidities of obesity. A recent systematic review found that the use of BMI for age with national reference data and cut-off points (such as the 95th percentile to define obesity) was superior to the Cole-International Obesity Task Force international approach for defining obesity based on BMI for age. The same systematic review also found no evidence that use of waist circumference for age improved the diagnosis of obesity, or the cardio-metabolic co-morbidities of obesity, in children and adolescents. Recent systematic reviews are therefore supportive of current guidelines that recommend percentile-based cut-offs relative to national reference data to (e.g. BMI at or above the 95th or 98th percentile in the UK) to define obesity for clinical applications in children and adolescents.

Association of duration of television viewing in early childhood with the subsequent development of asthma.

OBJECTIVE: To investigate whether duration of television (TV) viewing in young children is associated with subsequent development of asthma. METHODS: Children taking part in the Avon Longitudinal Study of Parents and Children (ALSPAC) with no wheeze up to the age of 3.5 years and follow-up data at 11.5 years of age took part in a prospective longitudinal cohort study. The main outcome measure was asthma, defined as doctor-diagnosed asthma by 7.5 years of age with symptoms and/or treatment in the previous 12 months at 11.5 years of age. Parental report of hours of TV viewing per day by the children was ascertained at 39 months. RESULTS: In children with no symptoms of wheeze at 3.5 years of age and follow-up data at 11.5 years of age, the prevalence of asthma was 6% (185/3065). Increased TV viewing at 3.5 years was associated with increased prevalence of asthma at 11.5 years of age (p for linear trend = 0.0003). Children who watched television for >2 h/day were almost twice as likely to develop asthma by 11.5 years of age as those watching TV for 1-2 h/day (adjusted odds ratio 1.8 (95% CI 1.2 to 2.6)). CONCLUSION: Longer duration of TV viewing in children with no symptoms of wheeze at 3.5 years of age was associated with the development of asthma in later childhood.

High prevalence of obesity in ambulatory children and adolescents with intellectual disability.

BACKGROUND: Obesity prevalence is unusually high among adults with intellectual disability (ID). There is limited and conflicting evidence on obesity prevalence among ambulatory children and adolescents with ID. The present study aimed to estimate obesity prevalence in this group and to compare with population prevalence. METHODS: Survey of nine schools (n = 206, 150 boys) for ambulatory children and adolescents with mild-moderate ID in Scotland in 2007. Obesity was defined as measured body mass index (BMI) at or above the 95th percentile relative to UK 1990 reference data, and using the international definition based on BMI. Obesity prevalence observed was compared against Scottish population data on obesity prevalence from the most recent nationally representative survey. RESULTS: Obesity prevalence (at or above 95th percentile for BMI) was 36%, and was significantly higher among those attending secondary schools compared with primary schools (P < 0.01). Prevalence of obesity was significantly higher than in the general paediatric population in both boys and girls (P < 0.01). CONCLUSIONS: The present study suggests that that obesity may be very prevalent among ambulatory children and adolescents with ID, and that increased obesity risk may begin in childhood.

Objectively measured habitual physical activity in a highly obesogenic environment.

BACKGROUND: While the prevalence of overweight and obesity among children continues to grow nationally, prevalence in the North-East of England is among the highest in the UK. The objective of this study was to investigate the habitual physical activity levels in a particularly obesogenic environment in the North-East of England. METHODS: Eight primary schools were selected using a stratified random sampling frame ranking average deprivation levels. Participating children (n = 246, mean age 10 years) wore an accelerometer (Actigraph, GT-256) over five consecutive days (weekend plus three weekdays). Total daily moderate-to-vigorous intensity physical activity was calculated using thresholds by Puyau and colleagues. RESULTS: Only 7% (17/246) of children were sufficiently active. Boys were more physically active than girls (766 +/- 268 vs. 641 +/- 202 counts/min, 95% CI for the difference 63-186 cpm.). Total physical activity was not influenced significantly by deprivation levels or weight status, and there were no significant differences in physical activity between school or weekend days. CONCLUSIONS: The North-East of England is a recognized 'hot spot' for paediatric obesity and the present study shows that low levels of habitual physical activity are typical. Choice of accelerometry threshold affects both the apparent amount of physical activity and the ability to detect groups with particularly low levels of physical activity.