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Background Observational studies have shown that higher cereal fiber intake is associated with reduced type 2 diabetes risk. However, it remains uncertain whether this association is causal. Objective This study evaluated the feasibility of an intervention to increase cereal fiber intake in children using breakfast cereals. Methods The study was a 2-arm parallel group randomized controlled trial in 9–10-y-old children, who received free supplies of high-fiber breakfast cereals (g3.5 g/portion) or low-fiber breakfast cereals (l1.0 g/portion) to eat daily for 1 mo with behavioral support to promote adherence. Children provided baseline and 1-mo fasting blood samples, physical measurements, and 24-h dietary recalls. The primary outcome was the group difference in change in plasma total alkylresorcinol (AR) concentration; secondary outcomes were group differences in nutrient intakes and adiposity indices. Analyses (complete case and multiple imputation) were conducted by regressing the final AR concentration on baseline AR in models adjusted for sex, ethnicity, age, and school (random effect). Results Two-hundred seventy-two children were randomly assigned (137 receiving a low-fiber and 135 a high-fiber diet) and 193 (71%) provided fasting blood samples at baseline and follow-up. Among randomized participants, median (IQR) of baseline AR was 43.1 (24.6–85.5) nmol/L and of cereal fiber intake was 4.5 (2.7–6.4) g; 87% of participants reported consuming the cereal on most or all days. Compared with changes in the low-fiber group, the high-fiber group had greater increases in AR (40.7 nmol/L; 95% CI: 21.7, 59.8 nmol/L, P l 0.0001) and in reported cereal fiber intake (2.9g/d; 95% CI: 2.0, 3.7 g; P l 0.0001). There were no appreciable differences in other secondary outcomes. Conclusions We have developed a simple and acceptable nutritional intervention that increases markers of daily cereal fiber intake in children. This intervention could be used to test whether increases in cereal fiber intake in children might reduce insulin resistance. This trial was registered at www.isrctn.com as ISRCTN33260236.

Accurate assessment of childhood adiposity is important both for individuals and populations. We compared fat mass (FM) predictions from a novel prediction model based on height, weight and demographic factors (height–weight equation) with FM from bioelectrical impedance (BIA) and dual-energy X-ray absorptiometry (DXA), using the deuterium dilution method as a reference standard. FM data from all four methods were available for 174 ALSPAC Study participants, seen 2002–2003, aged 11–12-years. FM predictions from the three approaches were compared to the reference standard using; R2, calibration (slope and intercept) and root mean square error (RMSE). R2 values were high from ‘height–weight equation’ (90%) but lower than from DXA (95%) and BIA (91%). Whilst calibration intercepts from all three approaches were close to the ideal of 0, the calibration slope from the ‘height–weight equation’ (slope = 1.02) was closer to the ideal of 1 than DXA (slope = 0.88) and BIA (slope = 0.87) assessments. The ‘height–weight equation’ provided more accurate individual predictions with a smaller RMSE value (2.6 kg) than BIA (3.1 kg) or DXA (3.4 kg). Predictions from the ‘height–weight equation’ were at least as accurate as DXA and BIA and were based on simpler measurements and open-source equation, emphasising its potential for both individual and population-level FM assessments.

Background Adequate sleep duration in childhood has important implications for social, mental, and physical well-being. Recent evidence has demonstrated declining sleep durations in children; therefore effective interventions to improve sleep measures are needed. Despite some trials suggesting that multi-behavioural interventions promoting bed-time routines may be beneficial, the effectiveness of such interventions has not been adequately quantified. Moreover, specific themes and strategies which increase sleep duration, and by how much, have not been formally quantified. Methods We carried out a systematic review and meta-analysis to quantify the effectiveness of sleep interventions to improve sleep duration in children within community settings (PROSPERO ID CRD42019160089). Studies involving infants under 1 year, those using medications, and targeting children with behavioural problems were excluded. We screened 11621 randomised control trials (RCT), after carrying out a search using combined text words and MeSH criteria in CENTRAL, MEDLINE, EMBASE, PSYCHINFO, Web of science, clinicaltrials.gov, and WHO trials databases. Full text screening of 341 studies identified 39 studies for data extraction. All screening was carried out independently by two reviewers using a web-based platform for systematic reviews. Results Studies were categorised by age as follows: 20% in >1–5 years of age, 25% >5–10 years, 33% >10–15 years, 22% >15 years. The mode of delivery of most interventions was face to face (74%). The intervention setting was most commonly school based (54%), with 21% based at home. Intervention duration was less than one month in 49% of studies. Qualitative data to describe each intervention was collected using a framework based on the TIDieR checklist. We are mapping this onto behavioural frameworks (COM-B, theoretical domains framework), to categorise interventions. Our initial analysis, from 9911 participants (4719, intervention, 5192 control) from 33 studies, suggests that mean differences in interventions increase sleep duration by 11 minutes (95% CI 6, 17 mins). However, caution is needed in interpreting this overall effect size (pooled using random effects) given the considerable heterogeneity across studies (I2 = 91%). The influence of study design characteristics in explaining heterogeneity (including age of participants, duration and type of intervention) will be outlined. Conclusion This review furthers our understanding of the most effective interventions to improve sleep duration in children and provides a platform to develop population level health interventions to improve sleep. Given challenges assimilating data, an overarching aim is to develop approaches that could be used to homogenise reporting in future RCTs in order that evidence can be summarised more easily.

ImportanceAdequate sleep duration is necessary for many aspects of child health, development, and well-being, yet sleep durations for children are declining, and effective strategies to increase sleep in healthy children remain to be elucidated.ObjectiveTo determine whether nonpharmaceutical interventions to improve sleep duration in healthy children are effective and to identify the key components of these interventions.Data SourcesCENTRAL, MEDLINE, Embase, PsycINFO, Web of Science Core collection, ClinicalTrials.gov, and WHO trials databases were searched from inception to November 15, 2021.Study SelectionRandomized clinical trials of interventions to improve sleep duration in healthy children were independently screened by 2 researchers. A total of 28 478 studies were identified.Data Extraction and SynthesisData were processed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) reporting guideline. Random-effects meta-analytic models were used to estimate pooled effect sizes.Main Outcomes and MeasuresDifference in sleep duration, measured in minutes.ResultsA total of 13 539 child participants from 45 randomized clinical trials were included. Of these, 6897 (50.9%) were in the intervention group and 6642 (49.1%) in the control group, and the mean age ranged from 18 months to 19 years. Pooled results indicate that sleep interventions were associated with 10.5 minutes (95% CI, 5.6-15.4) longer nocturnal sleep duration. There was substantial variation between trials. Sources of variation that were not associated with the study effect size included age group, whether the population was identified as having a sleep problem or being at a socioeconomic disadvantage (eg, coming from a low-income family or area), method of assessment of sleep duration (objective vs subjective), location of intervention delivery (home vs school), whether interventions were delivered in person or used parental involvement, whether behavioral theory was used, environmental change, or had greater or lower intensity. Interventions that included earlier bedtimes were associated with a 47-minute sleep extension (95% CI, 18.9-75.0; 3 trials) compared with remaining studies (7.4 minutes; 95% CI, 2.9-11.8; 42 trials) (P = .006 for group difference). Trials of shorter duration (6 months or less) had larger effects.Conclusions and RelevanceInterventions focused on earlier bedtimes may offer a simple, pragmatic, effective way to meaningfully increase sleep duration that could have important benefits for child health.

Peer reviewed: True, Acknowledgements: We thank John Reilly for his advice on data sources and data access; Cara L Eckhardt, Josephine Avila, Igor Y Kon, and Jinzhong Wang from the Eckhardt et al study23; and all staff involved in recruitment and data collection from the included studies. Data gathered from South Africa was supported by South Africa Medical Research Council and National Research Foundation., Objective To evaluate the performance of a UK based prediction model for estimating fat-free mass (and indirectly fat mass) in children and adolescents in non-UK settings. Design Individual participant data meta-analysis. Setting 19 countries. Participants 5693 children and adolescents (49.7% boys) aged 4 to 15 years with complete data on the predictors included in the UK based model (weight, height, age, sex, and ethnicity) and on the independently assessed outcome measure (fat-free mass determined by deuterium dilution assessment). Main outcome measures The outcome of the UK based prediction model was natural log transformed fat-free mass (lnFFM). Predictive performance statistics of R2 , calibration slope, calibration-in-the-large, and root mean square error were assessed in each of the 19 countries and then pooled through random effects meta-analysis. Calibration plots were also derived for each country, including flexible calibration curves. Results The model showed good predictive ability in non-UK populations of children and adolescents, providing R2 values of >75% in all countries and >90% in 11 of the 19 countries, and with good calibration (ie, agreement) of observed and predicted values. Root mean square error values (on fat-free mass scale) were

Key Points Question Is childhood fat mass (FM) more strongly associated with long-term type 2 diabetes (T2D) risk than childhood weight, independent of height? Findings In a population-based cohort study including more than 260 000 schoolchildren in Denmark, there were stronger associations (per kilogram increase) between childhood FM and adult T2D risk, independent of childhood height, than those observed for childhood weight. Meaning Results suggest that weight-based measures, currently used as the basis for childhood obesity assessment in the form of body mass index, were less strongly associated with adult T2D risk than childhood FM., This cohort study uses data from Copenhagen School Health Records Register to investigate the association of childhood fat mass and weight with adult-onset type 2 diabetes., Importance Childhood obesity, defined by cutoffs based on the weight-based marker of body mass index, is associated with adult type 2 diabetes (T2D) risk. Whether childhood fat mass (FM) is the driver of these associations is currently unknown. Objective To quantify and compare height-independent associations between childhood FM and weight with adult T2D risk in a historic Danish cohort. Design, Setting, and Participants This population-based retrospective cohort study included schoolchildren from The Copenhagen School Health Records Register born between January 1930 and December 1985 with follow-up to adulthood through December 31, 2015. Analyses were based on 269 913 schoolchildren aged 10 years with 21 896 established adult T2D cases and 261 192 children aged 13 years with 21 530 established adult T2D cases for whom childhood height and weight measurements, as well as predicted FM, were available. Statistical analyses were performed between April 2019 to August 2020. Exposures Childhood FM and weight at ages 10 and 13 years. Main Outcomes and Measures Diagnoses of T2D were established by linkage to national disease registers for adults aged at least 30 years. Sex-specific Cox regression quantified associations, adjusted for childhood height, which were evaluated within 5 birth-cohort groups. Group-specific results were pooled using random-effects meta-analyses accounting for heterogeneity across group-specific associations. Results This cohort study analyzed data from 269 913 children aged 10 years (135 940 boys [50.4%]) with 21 896 established adult T2D cases and 261 192 children aged 13 years (131 025 boys [50.2%]) with 21 530 established adult T2D cases. After adjusting for childhood height, increases in FM and weight (per kilogram) among boys aged 10 years were associated with elevated T2D risks at age 50 years of 12% (hazard ratio [HR], 1.12; 95% CI, 1.10-1.14) and 7% (HR, 1.07; 95% CI, 1.05-1.09), respectively, and among girls aged 10 years of 15% (HR, 1.15; 95% CI, 1.13-1.17) and 10% (HR, 1.10; 95% CI, 1.08-1.11), respectively. Among children aged 13 years, increases in FM and weight (per kilogram) were associated with increased T2D risks at age 50 years of 10% (HR, 1.10; 95% CI, 1.09-1.10) and 6% (HR, 1.06; 95% CI, 1.05-1.07) for boys, respectively, and of 10% (HR, 1.10; 95% CI, 1.10-1.11) and 7% (HR, 1.07; 95% CI, 1.06-1.08), respectively, for girls. Conclusions and Relevance This cohort study found that a 1-kg increase in childhood FM was more strongly associated with increased adult T2D risk than a 1-kg increase in weight, independent of childhood height. Information on FM, rather than weight-based measures, focuses on a modifiable component of weight that may be associated with adult T2D risk. These findings support the assessment of childhood FM in adiposity surveillance initiatives in an effort to reduce long-term T2D risk.

Background Previous research has reported associations between features of the residential built environment and physical activity but these studies have mainly been cross-sectional, limiting inference. This paper examines whether changes in a range of residential built environment features are associated with changes in measures of physical activity in adults. It also explores whether observed effects are moderated by socio-economic status. Methods Data from the Examining Neighbourhood Activity in Built Living Environments in London (ENABLE London) study were used. A cohort of 1278 adults seeking to move into social, intermediate, and market-rent East Village accommodation was recruited in 2013–2015, and followed up after 2 years. Accelerometer-derived steps (primary outcome), and GIS-derived measures of residential walkability, park proximity and public transport accessibility were obtained both at baseline and follow-up. Daily steps at follow-up were regressed on daily steps at baseline, change in built environment exposures and confounding variables using multilevel linear regression to assess if changes in neighbourhood walkability, park proximity and public transport accessibility were associated with changes in daily steps. We also explored whether observed effects were moderated by housing tenure as a marker of socio-economic status. Results Between baseline and follow-up, participants experienced a 1.4 unit (95%CI 1.2,1.6) increase in neighbourhood walkability; a 270 m (95%CI 232,307) decrease in distance to their nearest park; and a 0.7 point (95% CI 0.6,0.9) increase in accessibility to public transport. A 1 s.d. increase in neighbourhood walkability was associated with an increase of 302 (95%CI 110,494) daily steps. A 1 s.d. increase in accessibility to public transport was not associated with any change in steps overall, but was associated with a decrease in daily steps amongst social housing seekers (− 295 steps (95%CI − 595, 3), and an increase in daily steps for market-rent housing seekers (410 95%CI -191, 1010) (P-value for effect modification = 0.03). Conclusion Targeted changes in the residential built environment may result in increases in physical activity levels. However, the effect of improved accessibility to public transport may not be equitable, showing greater benefit to the more advantaged.

BackgroundNeighbourhood characteristics may affect mental health and well-being, but longitudinal evidence is limited. We examined the effect of relocating to East Village (the former London 2012 Olympic Athletes’ Village), repurposed to encourage healthy active living, on mental health and well-being.Methods1278 adults seeking different housing tenures in East village were recruited and examined during 2013–2015. 877 (69%) were followed-up after 2 years; 50% had moved to East Village. Analysis examined change in objective measures of the built environment, neighbourhood perceptions (scored from low to high; quality −12 to 12, safety −10 to 10 units), self-reported mental health (depression and anxiety) and well-being (life satisfaction, life being worthwhile and happiness) among East Village participants compared with controls who did not move to East Village. Follow-up measures were regressed on baseline for each outcome with group status as a binary variable, adjusted for age, sex, ethnicity, housing tenure and household clustering (random effect).ResultsParticipants who moved to East Village lived closer to their nearest park (528 m, 95% CI 482 to 575 m), in more walkable areas, and had better access to public transport, compared with controls. Living in East Village was associated with marked improvements in neighbourhood perceptions (quality 5.0, 95% CI 4.5 to 5.4 units; safety 3.4, 95% CI 2.9 to 3.9 units), but there was no overall effect on mental health and well-being outcomes.ConclusionDespite large improvements in the built environment, there was no evidence that moving to East Village improved mental health and well-being. Changes in the built environment alone are insufficient to improve mental health and well-being.

Background Interventions to encourage active modes of travel (walking, cycling) may improve physical activity levels, but longitudinal evidence is limited and major change in the built environment / travel infrastructure may be needed. East Village (the former London 2012 Olympic Games Athletes Village) has been repurposed on active design principles with improved walkability, open space and public transport and restrictions on residential car parking. We examined the effect of moving to East Village on adult travel patterns. Methods One thousand two hundred seventy-eight adults (16+ years) seeking to move into social, intermediate, and market-rent East Village accommodation were recruited in 2013–2015, and followed up after 2 years. Individual objective measures of physical activity using accelerometry (ActiGraph GT3X+) and geographic location using GPS travel recorders (QStarz) were time-matched and a validated algorithm assigned four travel modes (walking, cycling, motorised vehicle, train). We examined change in time spent in different travel modes, using multilevel linear regresssion models adjusting for sex, age group, ethnicity, housing group (fixed effects) and household (random effect), comparing those who had moved to East Village at follow-up with those who did not. Results Of 877 adults (69%) followed-up, 578 (66%) provided valid accelerometry and GPS data for at least 1 day (≥540 min) at both time points; half had moved to East Village. Despite no overall effects on physical activity levels, sizeable improvements in walkability and access to public transport in East Village resulted in decreased daily vehicle travel (8.3 mins, 95%CI 2.5,14.0), particularly in the intermediate housing group (9.6 mins, 95%CI 2.2,16.9), and increased underground travel (3.9 mins, 95%CI 1.2,6.5), more so in the market-rent group (11.5 mins, 95%CI 4.4,18.6). However, there were no effects on time spent walking or cycling. Conclusion Designing walkable neighbourhoods near high quality public transport and restrictions on car usage, may offer a community-wide strategy shift to sustainable transport modes by increasing public transport use, and reducing motor vehicle travel.

Summary Background The built environment can affect health behaviours, but longitudinal evidence is limited. We aimed to examine the effect of moving into East Village, the former London 2012 Olympic and Paralympic Games Athletes' Village that was repurposed on active design principles, on adult physical activity and adiposity. Methods In this cohort study, we recruited adults seeking new accommodation in East Village and compared physical activity and built environment measures with these data in control participants who had not moved to East Village. At baseline and after 2 years, we objectively measured physical activity with accelerometry and adiposity with body-mass index and bioimpedance, and we assessed objective measures of and participants' perceptions of change in their built environment. We examined the change in physical activity and adiposity between the East Village and control groups, after adjusting for sex, age group, ethnicity, housing tenure, and household (as a random effect). Findings We recruited participants for baseline assessment between Jan 24, 2013, and Jan 7, 2016, and we followed up the cohort after 2 years, between Feb 24, 2015, and Oct 24, 2017. At baseline, 1819 households (one adult per household) consented to initial contact by the study team. 1278 adults (16 years and older) from 1006 (55%) households participated at baseline; of these participants, 877 (69%) adults from 710 (71%) households were assessed after 2 years, of whom 441 (50%) participants from 343 (48%) households had moved to East Village. We found no effect associated with moving to East Village on daily steps, the time spent doing moderate-to-vigorous physical activity (either in total or in 10-min bouts or more), daily sedentary time, body-mass index, or fat mass percentage between participants who had moved to East Village and those in the control group, despite sizeable improvements in walkability and neighbourhood perceptions of crime and quality among the East Village group relative to their original neighbourhood at baseline. Interpretation Despite large improvements in neighbourhood perceptions and walkability, we found no clear evidence that moving to East Village was associated with increased physical activity. Improving the built environment on its own might be insufficient to increase physical activity. Funding National Institute for Health Research and National Prevention Research Initiative.

Objectives To develop and validate a prediction model for fat mass in children aged 4-15 years using routinely available risk factors of height, weight, and demographic information without the need for more complex forms of assessment. Design Individual participant data meta-analysis. Setting Four population based cross sectional studies and a fifth study for external validation, United Kingdom. Participants A pooled derivation dataset (four studies) of 2375 children and an external validation dataset of 176 children with complete data on anthropometric measurements and deuterium dilution assessments of fat mass. Main outcome measure Multivariable linear regression analysis, using backwards selection for inclusion of predictor variables and allowing non-linear relations, was used to develop a prediction model for fat-free mass (and subsequently fat mass by subtracting resulting estimates from weight) based on the four studies. Internal validation and then internal-external cross validation were used to examine overfitting and generalisability of the model’s predictive performance within the four development studies; external validation followed using the fifth dataset. Results Model derivation was based on a multi-ethnic population of 2375 children (47.8% boys, n=1136) aged 4-15 years. The final model containing predictor variables of height, weight, age, sex, and ethnicity had extremely high predictive ability (optimism adjusted R 2 : 94.8%, 95% confidence interval 94.4% to 95.2%) with excellent calibration of observed and predicted values. The internal validation showed minimal overfitting and good model generalisability, with excellent calibration and predictive performance. External validation in 176 children aged 11-12 years showed promising generalisability of the model (R 2 : 90.0%, 95% confidence interval 87.2% to 92.8%) with good calibration of observed and predicted fat mass (slope: 1.02, 95% confidence interval 0.97 to 1.07). The mean difference between observed and predicted fat mass was −1.29 kg (95% confidence interval −1.62 to −0.96 kg). Conclusion The developed model accurately predicted levels of fat mass in children aged 4-15 years. The prediction model is based on simple anthropometric measures without the need for more complex forms of assessment and could improve the accuracy of assessments for body fatness in children (compared with those provided by body mass index) for effective surveillance, prevention, and management of clinical and public health obesity.

Background: Increases in physical activity through active travel have the potential to have large beneficial effects on populations, through both better health outcomes and reduced motorized traffic. However accurately identifying travel mode in large datasets is problematic. Here we provide an open source tool to quantify time spent stationary and in four travel modes(walking, cycling, train, motorised vehicle) from accelerometer measured physical activity data, combined with GPS and GIS data. Methods: The Examining Neighbourhood Activities in Built Living Environments in London study evaluates the effect of the built environment on health behaviours, including physical activity. Participants wore accelerometers and GPS receivers on the hip for seven days. We time-matched accelerometer and GPS, and then extracted data from the commutes of 326 adult participants, using stated commute times and modes, which were manually checked to confirm stated travel mode. This yielded examples of five travel modes: walking, cycling, motorised vehicle, train and stationary. We used this example data to train a gradient boosted tree, a form of supervised machine learning algorithm, on each data point (131537 points), rather than on journeys. Accuracy during training was assessed using five-fold cross-validation. We also manually identified the travel behaviour of both 21 participants from ENABLE London (402749 points), and 10 participants from a separate study (STAMP-2, 210936 points), who were not included in the training data. We compared our predictions against this manual identification to further test accuracy and test generalisability. Results: Applying the algorithm, we correctly identified travel mode 97.3% of the time in cross-validation (mean sensitivity 96.3%, mean active travel sensitivity 94.6%). We showed 96.0% agreement between manual identification and prediction of 21 individuals’ travel modes (mean sensitivity 92.3%, mean active travel sensitivity 84.9%) and 96.5% agreement between the STAMP-2 study and predictions (mean sensitivity 85.5%, mean active travel sensitivity 78.9%). Conclusion: We present a generalizable tool that identifies time spent stationary and time spent walking with very high precision, time spent in trains or vehicles with good precision, and time spent cycling with moderate precisionIn studies where both accelerometer and GPS data are available this tool complements analyses of physical activity, showing whether differences in PA may be explained by differences in travel mode. All code necessary to replicate, fit and predict to other datasets is provided to facilitate use by other researchers.

Background There has been increasing interest in whether the built environmentinfluences health behaviours, but robust longitudinal evidence is limited. We assessed the effect of moving into East Village (the former London 2012 Olympic Games Athletes Village), a neighbourhood built on active design principles, on levels of physical activity (PA) and adiposity among adults. Methods A cohort of 1278 adults (16+) seeking to move into social, intermediate (a mixture of shared ownership, shared equity, affordable rent), and market-rent East Village accommodation were recruited in 2013–2015, and followed up after two years. Objective measures of PA using accelerometry (ActiGraph GT3X+), body mass index (BMI) and bioelectrical impedance (fat mass %) were made. We examined change in levels of PA and adiposity, using multilevel models adjusting for sex, age group, ethnicity, housing sector (fixed effects) and household (random effect), comparing those who moved to East Village (intervention group) with those who lived outside East Village (control group). Effects by housing sector and weekdays versus weekends for PA were also examined. Results 877 adults (69%) were followed-up, half had moved to East Village. Moving to East Village was associated with a small increase in daily steps (151, 95% CI −233, 534), more so in the intermediate sector (399, 95% CI −211, 1009) than in the social and market-rent sectors, but effects were not statistically significant. There were no differences in time spent in moderate-to-vigorous PA (MVPA) or any appreciable weekday versus weekend effects. There was no evidence of differences in time spent in light PA or sedentary time both overall and by housing sector with the exception of the market-rent group in whom moving to East Village was associated with a decrease in light PA (−13.0 mins, 95% CI −24.7,–1.2 mins). There were no effects of moving to East Village on BMI or fat mass% overall or by housing sector. Conclusion At two-year follow-up, moving to East Village, a neighbourhood designed for healthy active living, did not have beneficial, consistent effects on objectively measured physical activity or adiposity of public health importance.

ObjectivesThe neighbourhood environment is increasingly shown to be an important correlate of health. We assessed associations between housing tenure, neighbourhood perceptions, sociodemographic factors and levels of physical activity (PA) and adiposity among adults seeking housing in East Village (formerly London 2012 Olympic/Paralympic Games Athletes’ Village).SettingCross-sectional analysis of adults seeking social, intermediate and market-rent housing in East Village.Participants1278 participants took part in the study (58% female). Complete data on adiposity (body mass index (BMI) and fat mass %) were available for 1240 participants (97%); of these, a subset of 1107 participants (89%) met the inclusion criteria for analyses of accelerometer-based measurements of PA. We examined associations between housing sector sought, neighbourhood perceptions (covariates) and PA and adiposity (dependent variables) adjusted for household clustering, sex, age group, ethnic group and limiting long-standing illness.ResultsParticipants seeking social housing had the fewest daily steps (8304, 95% CI 7959 to 8648) and highest BMI (26.0 kg/m2, 95% CI 25.5kg/m2to 26.5 kg/m2) compared with those seeking intermediate (daily steps 9417, 95% CI 9106 to 9731; BMI 24.8 kg/m2, 95% CI 24.4 kg/m2to 25.2 kg/m2) or market-rent housing (daily steps 9313, 95% CI 8858 to 9768; BMI 24.6 kg/m2, 95% CI 24.0 kg/m2to 25.2 kg/m2). Those seeking social housing had lower levels of PA (by 19%–42%) at weekends versus weekdays, compared with other housing groups. Positive perceptions of neighbourhood quality were associated with higher steps and lower BMI, with differences between social and intermediate groups reduced by ~10% following adjustment, equivalent to a reduction of 111 for steps and 0.5 kg/m2for BMI.ConclusionsThe social housing group undertook less PA than other housing sectors, with weekend PA offering the greatest scope for increasing PA and tackling adiposity in this group. Perceptions of neighbourhood quality were associated with PA and adiposity and reduced differences in steps and BMI between housing sectors. Interventions to encourage PA at weekends and improve neighbourhood quality, especially among the most disadvantaged, may provide scope to reduce inequalities in health behaviour.

Body mass index (BMI) overweight/obesity thresholds in South Asian (SA) adults, at equivalent type 2 diabetes risk are lower than for white Europeans (WE). We aimed to define adjusted overweight/obesity thresholds for UK SA children based on equivalent insulin resistance (HOMA-IR) to WE children. In 1138 WE and 1292 SA children 9.0-10.9y, multi-level regression models quantified associations between BMI and HOMA-IR, by ethnic group. HOMA-IR levels for WE children were calculated at established overweight/obesity thresholds (9.5y,10.5y), based on UK90 BMI cut-offs. Quantified associations in SA children were then used to estimate adjusted SA weight status thresholds at the calculated HOMA-IR levels. At 9.5y, current WE BMI overweight and obesity thresholds were 19.2kg/m2, 21.3kg/m2 (boys) and 20.0kg/m2, 22.5kg/m2 (girls). At equivalent HOMA-IR, SA overweight and obesity thresholds were lower by 2.9kg/m2 (95%CI: 2.5–3.3kg/m2) and 3.2kg/m2 (95%CI: 2.7–3.6kg/m2) in boys and 3.0kg/m2 (95%CI: 2.6–3.4kg/m2) and 3.3kg/m2 (95%CI: 2.8–3.8kg/m2) in girls respectively. At these lower thresholds, overweight/obesity prevalences in SA children were approximately doubled (boys:61%,girls:56%). Patterns at 10.5y were similar. In conclusion, SA adjusted overweight/obesity thresholds based on equivalent IR, were markedly lower than BMI thresholds for WE children and defined more than half of SA children as overweight/obese.

Background The National Child Measurement Programme (NCMP) assesses patterns of overweight–obesity in English children. It uses body mass index (BMI), which overestimates body fatness in South Asian children and underestimates body fatness in black children of presumed African ethnicity. Using previously derived BMI adjustments, ensuring that adjusted BMI was similarly related to body fatness in South Asian, black, and white children, we reassessed population body fatness, overweight, and obesity patterns in these ethnic groups in the NCMP. Methods Analyses were based on 2012–13 NCMP data in 582 899 children aged 4–5 years and 485 362 children aged 10–11 years. Standard centile-based approaches defined weight status in each age-group before and after applying BMI adjustments, derived previously with the deuterium dilution method, for South Asian and black children. Findings Among white children, overweight–obesity prevalences were 23% (45 508/197 691) for boys and 21% (39 411/188 663) for girls in 4–5 year olds and 33% (52 635/160 278) and 30% (45 978/151 146), respectively, in 10–11 year olds. Before adjustment, South Asian children had lower overweight–obesity prevalences at 4–5 years (19% of boys [4485/23 191], 19% of girls [4176/22 109]; both p Interpretation Adjusted BMI data reveal a substantial excess of overweight–obesity among English South Asian children (at 4–5 years and especially at 10–11 years) and among black girls (aged 10–11 years), with important implications for prevention. These patterns are not apparent with the use of unadjusted BMI data, which systematically underestimated overweight–obesity prevalences in South Asian children and overestimated them in black children. Funding British Heart Foundation, National Institute for Health Research Collaboration for Leadership in Applied Health Research and Care (South London & North Thames).

The Examining Neighbourhood Activities in Built Living Environments in London (ENABLE London) study provides a unique opportunity to examine differences in mental health and well-being amongst adults seeking social, intermediate (affordable rent), and market-rent housing in a purpose built neighbourhood (East Village, the former London 2012 Olympic Athletes’ Village), specifically designed to encourage positive health behaviours. Multi-level logistic regression models examined baseline differences in levels of depression, anxiety and well-being across the housing groups. Compared with the intermediate group, those seeking social housing were more likely to be depressed, anxious and had poorer well-being after adjustment for demographic and health status variables. Further adjustments for neighbourhood perceptions suggest that compared with the intermediate group, perceived neighbourhood characteristics may be an important determinant of depression amongst those seeking social housing, and lower levels of happiness the previous day amongst those seeking market-rent housing. These findings add to the extensive literature on inequalities in health, and provide a strong basis for future longitudinal work that will examine change in depression, anxiety and well-being after moving into East Village, where those seeking social housing potentially have the most to gain., Highlights • A natural experiment examining baseline mental health and well-being in adults seeking three housing tenures in East Village. • Those seeking social housing are more likely to report depressive symptoms and low life satisfaction at baseline. • Differences in well-being outcomes across the housing groups can be partially explained by neighbourhood perceptions. • Those seeking social housing appear to have the most to gain by moving to East Village.

BACKGROUND: Associations between sleep duration and type 2 diabetes (T2D) risk markers in childhood have been little studied. We examined associations between self-reported sleep duration and T2D risk markers in children. METHODS: Cross-sectional study of 4525 multiethnic UK children aged 9 to 10 years. Sleep time was calculated from self-reported usual time of going to bed and getting up on a school day, validated in a subset using accelerometers. Fasting blood samples provided levels of serum lipids and insulin, plasma glucose, and HbA1c. Physical measures included height, weight, bioimpedance, and blood pressure. Multilevel linear regression models of anthropometric, T2D, and cardiovascular risk markers with sleep duration were adjusted for sex, age, month, ethnicity, socioeconomic position, observer (physical measures only), and random effect of school. RESULTS: On average, children slept 10.5 hours per night (95% range 8.0–12.0 hours). There were strong inverse graded relationships between sleep duration, adiposity, and diabetes risk markers. In adjusted models, a 1-hour-longer sleep duration was associated with 0.19 lower BMI (95% confidence interval [CI] 0.09 to 0.28), 0.03 kg/m5 lower fat mass index (95% CI 0.00 to 0.05 kg/m5), 2.9% lower homeostasis model assessment insulin resistance (95% CI 1.2% to 4.4%), and 0.24% lower fasting glucose (95% CI 0.03% to 0.44%); there was no association with HbA1c or cardiovascular risk. Associations with insulin and glucose remained after an additional adjustment for adiposity markers. CONCLUSIONS: The finding of an inverse association between sleep duration and T2D risk markers in childhood is novel. Intervention studies are needed to establish the causality of these associations, which could provide a simple strategy for early T2D prevention.

Background High body fat (BF) levels in UK children are a major problem, with particular concerns about children of South Asian and Black (presumed African) origin. However, available national data are based on body mass index (BMI), which underestimates BF in South Asian children and overestimates BF in Black children. We reassessed childhood BF patterns and time trends between 2007–08 and 2012–13 using ethnicity-specific BMI adjustments to derive adjusted BMI levels (aBMI) that were related to BF in an equivalent way across South Asian, Black and White children. Methods Analyses were based on National Child Measurement Programme (NCMP) data from 2007–08 to 2012–13 in 3,195,323 aged 4–5 years and 2,962,673 children aged 10–11 years. aBMI values were derived for South Asian and Black children in a separate study, using body composition measured by the deuterium dilution method. These aBMI values related to BF similarly in South Asians, Blacks and Whites. To examine time trends in mean aBMI and in overweight-obesity prevalence by ethnicity, multiple linear regression and logistic regression analyses were used respectively. Results In the first year (2007–08), mean aBMIs in 10–11 year-olds (boys, girls) compared with Whites (18.64, 18.98 kg/m 2 ) were higher in South Asians (20.08, 19.94 kg/m 2 ; both p 2 ; both p 2 ) were significantly higher in South Asians (0.16, 0.32 kg/m 2 ; both p 2 ; p=0.01, p=0.41*). Among South Asians, both means and mean changes were greater among Bangladeshis and Pakistanis than Indians. Ethnic differences in mean aBMI levels were similar in younger children, but time trends were not as pronounced. Analyses examining overweight-obesity prevalence showed similar findings to those using mean aBMI. Parallel analyses in unadjusted BMI (the usual NCMP data presentation) showed similar time trends but different mean BMI patterns; Black children had highest mean unadjusted BMI values while White boys and South Asian girls had the lowest. *P-Value for difference from Whites Conclusion These analyses using aBMI data emphasise the particularly high (and rising) burden of BF among UK South Asians, compared with both White and Black children. These patterns are not adequately described by unadjusted BMI data, which tend to overestimate the BF burden in Black children and underestimate that in South Asians.

Background The relationship between physical fitness and risk markers for type 2 diabetes (T2D) in children and the contribution to ethnic differences in these risk markers have been little studied. We examined associations between physical fitness and early risk markers for T2D and cardiovascular disease in 9‐ to 10‐year‐old UK children. Methods Cross‐sectional study of 1445 9‐ to 10‐year‐old UK children of South Asian, black African‐Caribbean and white European origin. A fasting blood sample was used for measurement of insulin, glucose (from which homeostasis model assessment [HOMA]‐insulin resistance [IR] was derived), glycated hemoglobin (HbA1c), urate, C‐reactive protein (CRP), and lipids. Measurements of blood pressure (BP) and fat mass index (FMI) were made; physical activity was measured by accelerometry. Estimated VO2 max was derived from a submaximal fitness step test. Associations were estimated using multilevel linear regression. Results Higher VO2 max was associated with lower FMI, insulin, HOMA‐IR, HbA1c, glucose, urate, CRP, triglycerides, LDL‐cholesterol, BP and higher HDL‐cholesterol. Associations were reduced by adjustment for FMI, but those for insulin, HOMA‐IR, glucose, urate, CRP, triglycerides and BP remained statistically significant. Higher levels of insulin and HOMA‐IR in South Asian children were partially explained by lower levels of VO2max compared to white Europeans, accounting for 11% of the difference. Conclusions Physical fitness is associated with risk markers for T2D and CVD in children, which persist after adjustment for adiposity. Higher levels of IR in South Asians are partially explained by lower physical fitness levels compared to white Europeans. Improving physical fitness may provide scope for reducing risks of T2D.

BACKGROUND/OBJECTIVES: Body mass index (BMI) (weight per height(2)) is the most widely used marker of childhood obesity and total body fatness (BF). However, its validity is limited, especially in children of South Asian and Black African origins. We aimed to quantify BMI adjustments needed for UK children of Black African and South Asian origins so that adjusted BMI related to BF in the same way as for White European children. METHODS: We used data from four recent UK studies that made deuterium dilution BF measurements in UK children of White European, South Asian and Black African origins. A height-standardized fat mass index (FMI) was derived to represent BF. Linear regression models were then fitted, separately for boys and girls, to quantify ethnic differences in BMI-FMI relationships and to provide ethnic-specific BMI adjustments. RESULTS: We restricted analyses to 4-12 year olds, to whom a single consistent FMI (fat mass per height(5)) could be applied. BMI consistently underestimated BF in South Asians, requiring positive BMI adjustments of +1.12 kg m(-)(2) (95% confidence interval (CI): 0.83, 1.41 kg m(-)(2); P

OBJECTIVE Energy intake, energy density, and nutrient intakes are implicated in type 2 diabetes risk in adults, but little is known about their influence on emerging type 2 diabetes risk in childhood. We examined these associations in a multiethnic population of children. RESEARCH DESIGN AND METHODS This was a cross-sectional study of 2,017 children predominantly of white European, South Asian, and black African-Caribbean origin aged 9–10 years who had a detailed 24-h dietary recall and measurements of body composition and provided a fasting blood sample for measurements of plasma glucose, HbA1c, and serum insulin; homeostasis model assessment of insulin resistance was also derived. RESULTS Energy intake was positively associated with insulin resistance. After the removal of 176 participants with implausible energy intakes (unlikely to be representative of habitual intake), energy intake was more strongly associated with insulin resistance and was also associated with glucose and fat mass index. Energy density was also positively associated with insulin resistance and fat mass index. However, in mutually adjusted analyses, the associations for energy intake remained while those for energy density became nonsignificant. Individual nutrient intakes showed no associations with type 2 diabetes risk markers. CONCLUSIONS Higher total energy intake was strongly associated with high levels of insulin resistance and may help to explain emerging type 2 diabetes risk in childhood. Studies are needed to establish whether reducing energy intake produces sustained favorable changes in insulin resistance and circulating glucose levels.

OBJECTIVE Ethnic differences in type 2 diabetes risk between South Asians and white Europeans originate before adult life and are not fully explained by higher adiposity levels in South Asians. Although metabolic sensitivity to adiposity may differ between ethnic groups, this has been little studied in childhood. We have therefore examined the associations among adiposity, insulin resistance, and glycemia markers in children of different ethnic origins. RESEARCH DESIGN AND METHODS Cross-sectional study of 4,633 9- to 10-year-old children (response rate 68%) predominantly of South Asian, black African-Caribbean, and white European origin (n = 1,266, 1,176, and 1,109, respectively) who had homeostasis model assessments of insulin resistance (HOMA-IR), glycemia markers (HbA1c and fasting glucose), and adiposity (BMI, waist circumference, skinfold thicknesses, and bioimpedance [fat mass]). RESULTS All adiposity measures were positively associated with HOMA-IR in all ethnic groups, but associations were stronger among South Asians compared to black African-Caribbeans and white Europeans. For a 1-SD increase in fat mass percentage, percentage differences in HOMA-IR were 37.5% (95% CI 33.3–41.7), 29.7% (25.8–33.8), and 27.0% (22.9–31.2), respectively (P interaction < 0.001). All adiposity markers were positively associated with HbA1c in South Asians and black African-Caribbeans but not in white Europeans; for a 1-SD increase in fat mass percentage, percentage differences in HbA1c were 0.04% (95% CI 0.03–0.06), 0.04% (0.02–0.05), and 0.02% (−0.00 to 0.04), respectively (P interaction < 0.001). Patterns for fasting glucose were less consistent. CONCLUSIONS South Asian children are more metabolically sensitive to adiposity. Early prevention or treatment of childhood obesity may be critical for type 2 diabetes prevention, especially in South Asians.

Background Higher screen time is associated with type 2 diabetes (T2D) risk in adults, but the association with T2D risk markers in children is unclear. We examined associations between self-reported screen time and T2D risk markers in children. Methods Survey of 4495 children aged 9–10 years who had fasting cardiometabolic risk marker assessments, anthropometry measurements and reported daily screen time; objective physical activity was measured in a subset of 2031 children. Results Compared with an hour or less screen time daily, those reporting screen time over 3 hours had higher ponderal index (1.9%, 95% CI 0.5% to 3.4%), skinfold thickness (4.5%, 0.2% to 8.8%), fat mass index (3.3%, 0.0% to 6.7%), leptin (9.2%, 1.1% to 18.0%) and insulin resistance (10.5%, 4.9% to 16.4%); associations with glucose, HbA1c, physical activity and cardiovascular risk markers were weak or absent. Associations with insulin resistance remained after adjustment for adiposity, socioeconomic markers and physical activity. Conclusions Strong graded associations between screen time, adiposity and insulin resistance suggest that reducing screen time could facilitate early T2D prevention. While these observations are of considerable public health interest, evidence from randomised controlled trials is needed to suggest causality.

OBJECTIVE: Little is known about levels of physical fitness in children from different ethnic groups in the UK. We therefore studied physical fitness in UK children (aged 9-10 years) of South Asian, black African-Caribbean and white European origin. DESIGN: Cross-sectional study. SETTING: Primary schools in the UK. PARTICIPANTS: 1625 children (aged 9-10 years) of South Asian, black African-Caribbean and white European origin in the UK studied between 2006 and 2007. OUTCOME MEASURES: A step test assessed submaximal physical fitness from which estimated VO2 max was derived. Ethnic differences in estimated VO2 max were estimated using multilevel linear regression allowing for clustering at school level and adjusting for age, sex and month as fixed effects. RESULTS: The study response rate was 63%. In adjusted analyses, boys had higher levels of estimated VO2 max than girls (mean difference 3.06 mL O2/min/kg, 95% CI 2.66 to 3.47, p

Objective— To examine the association between cardiovascular risk factors and retinal arteriolar tortuosity in a multi-ethnic child population. Methods and Results— Cross sectional study of 986 UK primary school children of South Asian, black African Caribbean, and white European origin aged 10 to 11 years. Anthropometric measurements and retinal imaging were carried out and a fasting blood sample collected. Digital images of retinal arterioles were analyzed using a validated semiautomated measure of tortuosity. Associations between tortuosity and cardiometabolic risk factors were analyzed using multi-level linear regression, adjusted for gender, age, ethnicity, arteriole branch status, month, and school. Levels of arteriolar tortuosity were similar in boys and girls and in different ethnic groups. Retinal arteriolar tortuosity was positively associated with levels of triglyceride, total and LDL cholesterol, and systolic and diastolic blood pressure. One standard deviation increases in these risk factors were associated with 3.7% (95% CI: 1.2%, 6.4%), 3.3% (0.9%, 5.8%), 3.1% (0.6%, 5.6%), 2.0% (−0.3%, 4.2%), and 2.3% (0.1%, 4.6%) increases in tortuosity, respectively. Adiposity, insulin resistance, and blood glucose showed no associations with tortuosity. Conclusion— Established cardiovascular risk factors, strongly linked to coronary heart disease in adulthood, may influence retinal arteriolar tortuosity at the end of the first decade of life.

Aims/hypothesis Physical inactivity is implicated in unfavourable patterns of obesity and cardiometabolic risk in childhood. However, few studies have quantified these associations using objective physical activity measurements in children from different ethnic groups. We examined these associations in UK children of South Asian, black African-Caribbean and white European origin. Methods This was a cross-sectional study of 2,049 primary school children in three UK cities, who had standardised anthropometric measurements, provided fasting blood samples and wore activity monitors for up to 7 days. Data were analysed using multilevel linear regression and allowing for measurement error. Results Overall physical activity levels showed strong inverse graded associations with adiposity markers (particularly sum of skinfold thicknesses), fasting insulin, HOMA insulin resistance, triacylglycerol and C-reactive protein; for an increase of 100 counts of physical activity per min of registered time, levels of these factors were 12.2% (95% CI 10.2–14.1%), 10.2% (95% CI 7.5–12.8%), 10.2% (95% CI 7.5–12.8%), 5.8% (95% CI 4.0–7.5%) and 19.2% (95% CI 13.9–24.2%) lower, respectively. Similar increments in physical activity levels were associated with lower diastolic blood pressure (1.0 mmHg, 95% CI 0.6–1.5 mmHg) and LDL-cholesterol (0.04 mmol/l, 95% CI 0.01–0.07 mmol/l), and higher HDL-cholesterol (0.02 mmol/l, 95% CI 0.01–0.04 mmol/l). Moreover, associations were broadly similar in strength in all ethnic groups. All associations between physical activity and cardiometabolic risk factors were reduced (albeit variably) after adjustment for adiposity. Conclusions/interpretation Objectively measured physical activity correlates at least as well with obesity and cardiometabolic risk factors in South Asian and African-Caribbean children as in white European children, suggesting that efforts to increase activity levels in such groups would have equally beneficial effects.

In the UK, South Asian adults have increased risks of CHD, type 2 diabetes and central obesity. Black African-Caribbeans, in contrast, have increased risks of type 2 diabetes and general obesity but lower CHD risk. There is growing evidence that these risk differences emerge in early life and that nutritional factors may be important. We have therefore examined the variations in nutritional composition of the diets of South Asian, black African-Caribbean and white European children, using 24 h recalls of dietary intake collected during a cross-sectional survey of cardiovascular health in eighty-five primary schools in London, Birmingham and Leicester. In all, 2209 children aged 9–10 years took part, including 558 of South Asian, 560 of black African-Caribbean and 543 of white European ethnicity. Compared with white Europeans, South Asian children reported higher mean total energy intake; their intakes of total fat, polyunsaturated fat and protein (both absolute and as proportions of total energy intake) were higher and their intakes of carbohydrate as a proportion of energy (particularly sugars), vitamin C and D, Ca and haem Fe were lower. These differences were especially marked for Bangladeshi children. Black African-Caribbean children had lower intakes of total and saturated fat (both absolute and as proportions of energy intake), NSP, vitamin D and Ca. The lower total and saturated fat intakes were particularly marked among black African children. Appreciable ethnic differences exist in the nutritional composition of children's diets, which may contribute to future differences in chronic disease risk.

IntroductionHIV remains underdiagnosed. Guidelines recommend routine HIV testing in primary care, but evidence on implementing testing is lacking. In a previous study, the Rapid HIV Assessment 2 (RHIVA2) cluster randomised controlled trial, we showed that providing training and rapid point-of-care HIV testing at general practice registration (RHIVA2 intervention) in Hackney led to cost-effective, increased and earlier diagnosis of HIV. However, interventions effective in a trial context may be less so when implemented in routine practice. We describe the protocol for an MRC phase IV implementation programme, evaluating the impact of rolling out the RHIVA2 intervention in a post-trial setting. We will use a longitudinal study to examine if the post-trial implementation in Hackney practices is effective and cost-effective, and a cross-sectional study to compare Hackney with two adjacent boroughs providing usual primary care (Newham) and an enhanced service promoting HIV testing in primary care (Tower Hamlets).Methods and analysisService evaluation using interrupted time series and cost-effectiveness analyses. We will include all general practices in three contiguous high HIV prevalence East London boroughs. All adults aged 16 and above registered with the practices will be included. The interventions to be examined are: a post-trial RHIVA2 implementation programme (including practice-based education and training, external quality assurance, incentive payments for rapid HIV testing and incorporation of rapid HIV testing in the sexual health Local Enhanced Service) in Hackney; the general practice sexual health Network Improved Service in Tower Hamlets and usual care in Newham. Coprimary outcomes are rates of HIV testing and new HIV diagnoses.Ethics and disseminationThe chair of the Camden and Islington NHS Research Ethics Committee, London, has endorsed this programme as an evaluation of routine care. Study results will be published in peer-reviewed journals and reported to commissioners.

The 2004 UK Quality and Outcomes Framework (QOF) remunerates general practitioners for achieving a target blood pressure (BP) ofor=150/90 mm Hg for patients with ischaemic heart disease, stroke and hypertension. Using the DIN-LINK GP database, we investigated whether introducing the target altered BP recording. We extracted 3 164 189 BP measurements from 236 467 patients, with the above diagnoses from 2000 to 2005. Treatment was assessed by Read codes indicating prescriptions for antihypertensive drugs. Over this period, recorded systolic BP (SBP) fell: 36% had an SBP150 mm Hg in 2000-2001, and only 19% in 2004-2005. However, there was a trend towards recording systolic values just below, rather than just above the 150 cut-off. In 2000-2001, 2.3% of patients had 148-149 recorded and 1.8% had 151-152. In 2004-2005, the figures were 4.2 and 1.3%, respectively. By smoothing the distribution we estimate that the true percentage of patients with SBP150 mm Hg in 2004-2005 was 23%, rather than the 19% recorded. Moreover, patients with a recorded SBP=148-149 were more likely to have a recorded diastolic BPor=90 (93%) than patients with SBP=151-152 (78%). However, patients just below the 150 mm Hg cut-off received more antihypertensive treatment than those just above it (odds ratio=1.20, 95% confidence interval 1.01-1.41). We conclude that blood pressure levels in UK primary care have continued to fall through the introduction of QOF, offering significant public health benefits in the future. This fall has been exaggerated due to values being clustered just below the QOF target, but there is no evidence of adverse effects of this on clinical management.

Aim To examine whether low circulating vitamin C concentrations and low fruit and vegetable intakes were associated with insulin resistance and other Type 2 diabetes risk markers in childhood. Methods We conducted a cross‐sectional, school‐based study in 2025 UK children aged 9–10 years, predominantly of white European, South‐Asian and black African origin. A 24‐h dietary recall was used to assess fruit, vegetable and vitamin C intakes. Height, weight and fat mass were measured and a fasting blood sample collected to measure plasma vitamin C concentrations and Type 2 diabetes risk markers. Results In analyses adjusting for confounding variables (including socio‐economic status), a one interquartile range higher plasma vitamin C concentration (30.9 μmol/l) was associated with a 9.6% (95% CI 6.5, 12.6%) lower homeostatic model assessment of insulin resistance value, 0.8% (95% CI 0.4, 1.2%) lower fasting glucose, 4.5% (95% CI 3.2, 5.9%) lower urate and 2.2% (95% CI 0.9, 3.4%) higher HDL cholesterol. HbA1c concentration was 0.6% (95% CI 0.2, 1.0%) higher. Dietary fruit, vegetable and total vitamin C intakes were not associated with any Type 2 diabetes risk markers. Lower plasma vitamin C concentrations in South‐Asian and black African‐Caribbean children could partly explain their higher insulin resistance. Conclusions Lower plasma vitamin C concentrations are associated with insulin resistance and could partly explain ethnic differences in insulin resistance. Experimental studies are needed to establish whether increasing plasma vitamin C can help prevent Type 2 diabetes at an early stage., What's new? We examined the cross‐sectional associations between intakes of fruit, vegetables and vitamin C, circulating vitamin C concentrations and insulin resistance in UK children.Circulating vitamin C concentration was inversely associated with insulin resistance, while intakes of fruit, vegetable and vitamin C were unrelated to insulin resistance.Low levels of circulating vitamin C concentrations in UK South‐Asian children could contribute to their higher insulin resistance.Further studies (including trials) are needed to examine the association of vitamin C with insulin resistance and its potential implications for Type 2 diabetes prevention.

Using data from the Prevention of Pelvic Infection (POPI) chlamydia screening trial, we compared the characteristics of female students who did or did not get tested for chlamydia outside the trial during 12 months’ follow-up. Of the 2529 women in the trial, we excluded 68 chlamydia positives in the intervention group who were referred for treatment at baseline. Of the remaining 2461 women, 1980 (80%) answered the question about testing during follow-up on their 12 months’ questionnaire and were included in the cohort. Of 1980 respondents, 529 (27%) reported having an independent chlamydia test, including 30 (48%) of 63 women with undiagnosed chlamydia at baseline. Predictors of testing included having undiagnosed chlamydia at baseline (adjusted odds ratio 2.44; 95% confidence interval 1.39–4.28), ≥2 sexual partners in the year prior to baseline (OR 1.99; 95% CI 1.60–2.48), history of sexually transmitted infection (1.63: 1.20–2.22); symptoms of pelvic discomfort, dyspareunia, abnormal vaginal discharge or inter-menstrual bleeding (1.38; 1.09–1.73); and black ethnicity (1.37, 1.06–1.76). Although more women with risk factors got tested, half of women with undiagnosed chlamydia did not get tested. To optimise detection of chlamydia, testing should be offered routinely.

Background Current UK health guidelines suggest a minimum of 150 minutes of moderate intensity physical activity per week to decrease the risk of several non-communicable diseases. Active travel, i.e. travel powered by physical activity such as walking or cycling, represents an opportunity to increase people’s overall level of activity without dramatic changes to other parts of their lifestyle. For measurements of activity to be reliable they must be objective. Physical activity is frequently assessed objectively using accelerometers, with their location determined by GPS devices. However, if travel behaviour is to be properly understood, this accelerometer and GPS data needs to be separated into different travel modes. The ENABLE study (Examining Neighbourhood Activities in Built Living Environments) is a longitudinal natural experiment based in London, UK, which is assessing the effects of moving to a physical activity-supportive environment on participants’ travel behaviour, and which offers an excellent opportunity to develop automated methods to identify and quantify travel behaviour. Methods At baseline, 1089 adults had their physical activity assessed using accelerometers and GPS devices. We present a method for the identification of five travel modes from this baseline data (Walking, Cycling, Vehicles, Trains, Not travelling), using accelerometer counts, GPS-derived speed data and freely available GIS data. We use a supervised-machine learning algorithm based on Bayesian networks. We present the creation of training data from survey questionnaires, data processing, network training and prediction and post-processing of output. In post-processing we also identify points at which underground train journeys may have taken place, removing a potential bias of GPS-based objective measurement of travel behaviour. Results Our trained Bayesian network predicts five travel modes with 88.4% correct prediction across all travel modes (lowest cycling 75.0%, highest walking 94.3%) After application of post-processing rules, this increases to 90.1% overall correct prediction (lowest cycling 77.2%, highest walking 95.0%). Underground train journeys, which give no GPS signal, are identified using simple rules. A total of 3154 potential journeys are identified, of which 2343 were correct after manual validation. Conclusions Our identification method successfully distinguishes between five different travel modes with high accuracy, using easily attainable objective data and is implemented in the free statistical software R. Our method removes the need for the collection of time consuming training data, and allows analysis of differences between active and passive travel methods.

OBJECTIVE Ethnic differences in type 2 diabetes risk between South Asians and white Europeans originate before adult life and are not fully explained by higher adiposity levels in South Asians. Although metabolic sensitivity to adiposity may differ between ethnic groups, this has been little studied in childhood. We have therefore examined the associations among adiposity, insulin resistance, and glycemia markers in children of different ethnic origins. RESEARCH DESIGN AND METHODS Cross-sectional study of 4,633 9- to 10-year-old children (response rate 68%) predominantly of South Asian, black African-Caribbean, and white European origin (n = 1,266, 1,176, and 1,109, respectively) who had homeostasis model assessments of insulin resistance (HOMA-IR), glycemia markers (HbA1c and fasting glucose), and adiposity (BMI, waist circumference, skinfold thicknesses, and bioimpedance [fat mass]). RESULTS All adiposity measures were positively associated with HOMA-IR in all ethnic groups, but associations were stronger among South Asians compared to black African-Caribbeans and white Europeans. For a 1-SD increase in fat mass percentage, percentage differences in HOMA-IR were 37.5% (95% CI 33.3–41.7), 29.7% (25.8–33.8), and 27.0% (22.9–31.2), respectively (P interaction < 0.001). All adiposity markers were positively associated with HbA1c in South Asians and black African-Caribbeans but not in white Europeans; for a 1-SD increase in fat mass percentage, percentage differences in HbA1c were 0.04% (95% CI 0.03–0.06), 0.04% (0.02–0.05), and 0.02% (−0.00 to 0.04), respectively (P interaction < 0.001). Patterns for fasting glucose were less consistent. CONCLUSIONS South Asian children are more metabolically sensitive to adiposity. Early prevention or treatment of childhood obesity may be critical for type 2 diabetes prevention, especially in South Asians.

Background East Village (formerly the 2012 London Olympic Games Athletes' Village) was designed for healthy active living. The Examining Neighbourhood Activities in Built Living Environments in London (ENABLE London) study is a 2 year longitudinal study examining whether health behaviours show sustained change among individuals moving to East Village, compared with a control population living outside. We aimed to report baseline characteristics of participants in this study. Methods All adults seeking social, intermediate, or market-rent accommodation in East Village were recruited. Self-rated health, wellbeing, anxiety, depression, and perceptions of the local built environment were ascertained through questionnaires. Accelerometers were used to assess physical activity. Body-mass index (BMI) was calculated. Findings The baseline cohort, before any move to East Village, comprises 1278 adults. Social housing participants were older (n=520, median age 37 years [IQR 28–45]) than those from intermediate (524, 31 [27–36]) and market-rent sectors (234, 28 [25–33]), were mostly women (n=379, 73% vs 251, 48% vs 103, 44%), and non-white (424, 82% vs 166, 32% vs 71, 30%). Baseline findings show that those in social housing were least likely to agree with enjoying living in their area (n=275, 53%) and walking in their neighbourhood (256, 49%) compared with the intermediate (361, 69% vs 318, 61%) and market-rent sectors (167, 71% vs 142, 61%). A graded increase of very good or good health status was reported across housing sectors (social n=393, 76%; intermediate 463, 88%; market-rent 212, 90%), with a decrease in abnormal levels of anxiety (80, 15%; 57, 11%; 23, 10%) and depression (58, 11%; 21, 4%; 6, 3%). The social sector recorded fewer daily steps (n=509, mean number of steps 7750 [SD 3312]), compared with intermediate (504, 9699 [2916]) and market-rent sectors (221, 9361 [2992]). BMI was higher in social sector participants (n=515, 27·3 kg/m 2 [SD 6·0]) than in those in intermediate (518, 24·8 [4·6]) and market-rent sectors (226, 24·2 [4·0]). To date, 324 (54%) of 605 participants have moved to East Village. Interpretation The ENABLE London study offers a unique opportunity for a natural experiment. These baseline data provide strong evidence of marked differences in perceptions of the built environment, and health behaviours across housing sectors. 2 year follow-up of the cohort will measure change in these health outcomes, associated with moving to the same environment. Funding Medical Research Council National Prevention Research Initiative (grant MR/J000345/1) and National Institute for Health Research (grant 12/211/69).

Background Excess childhood body fatness, overweightness, and obesity are a major public health challenge in the UK. Accurate assessments, usually based on body-mass index (BMI), are crucial. However, recent studies have demonstrated that BMI underestimates body fatness in South Asian children and overestimates it in black African children. These errors are a concern in these ethnic minority populations, particularly UK South Asians, who are at high risk of obesity, type 2 diabetes, and cardiovascular disease. We aimed to develop BMI adjustments for these children to ensure that BMI relates to body fatness in the same way as for white European children. Methods Four recent UK population-based studies, which used deuterium dilution assessments of fat mass as a reference method, were pooled to include 1725 children (52% girls) aged 4–12 years (mean 9·3, SD 1·6) of white European, South Asian, and black African origins. A height-standardised fat-mass index (FMI) was derived to represent body fatness. Linear regression models were fitted, separately by sex, to quantify ethnic differences in BMI–FMI associations and to provide ethnic-specific BMI adjustments. Findings The FMI derived for this study population and used in analyses was fat mass/height 5 , which was independent of height for the 4–12-year age-group. BMI consistently underestimated body fatness in South Asians, requiring a BMI adjustment of +1·12 kg/m 2 (95% CI 0·83–1·41) for boys and +1·07 (0·74–1·39) for girls, irrespective of age and FMI. BMI overestimated body fatness in black Africans. However, adjustments for black African children were more complex, with statistically significant interactions between black African ethnicity and FMI (p=0·004 boys, p=0·003 girls) and between FMI and age-group (p 2 for boys and between −0·22 and −2·86 kg/m 2 for girls for unadjusted BMI values of 13 kg/m 2 in 10–12 year-olds and 25 kg/m 2 in 4–6 year-olds, respectively. Interpretation BMI underestimated body fatness in South Asians and overestimated it in black Africans. Ethnic-specific adjustments—increasing BMI in South Asians and reducing BMI in black Africans—can improve the accuracy of body fatness assessment in these children. Funding This work was supported by the British Heart Foundation (grant ref PG/15/19/31336) and National Institute for Health Research Collaboration for Leadership in Applied Health Research and Care (South London) (grant ref CLAHRC-2013-10022). Primary data collection was funded by the British Heart Foundation (PG/11/42/28895), BUPA Foundation (TBF-S09-019), Child Growth Foundation (GR 10/03), and Wellcome Trust (WT094129MA). MF is supported by Great Ormond Street Hospital Childrens' Charity.

Purpose: The Examining Neighbourhood Activities in Built Living Environments in London (ENABLE London) project is a natural experiment which aims to establish whether physical activity and other health behaviours show sustained changes among individuals and families relocating to East Village (formerly the London 2012 Olympics Athletes’ Village), when compared with a control population living outside East Village throughout.Participants: Between January 2013 and December 2015, 1497 individuals from 1006 households were recruited and assessed (at baseline) (including 392 households seeking social housing, 421 seeking intermediate and 193 seeking market rent homes). The 2-year follow-up rate is 62% of households to date, of which 57% have moved to East Village. Findings to date: Assessments of physical activity (measured objectively using accelerometers) combined with Global Positioning System technology and Geographic Information System mapping of the local area are being used to characterise physical activity patterns and location among study participants and assess the attributes of the environments to which they are exposed. Assessments of body composition, based on weight, height and bioelectrical impedance, have been made and detailed participant questionnaires provide information on socioeconomic position, general health/health status, well-being, anxiety, depression, attitudes to leisure time activities and other personal, social and environmental influences on physical activity, including the use of recreational space and facilities in their residential neighbourhood.Future plans: The main analyses will examine the changes in physical activity, health and well-being observed in the East Village group compared withcontrols and the influence of specific elements of the built environment on observed changes. The ENABLE London project exploits a unique opportunity toevaluate a ‘natural experiment’, provided by the building and rapid occupation of East Village. Findings from the study will be generalisable to other urban residential housing developments, and will help inform future evidence-based urban planning.

Objective— Short leukocyte telomere length (LTL) is associated with cardiovascular (CV) disease in adulthood. However, the biological basis of this association remains unclear. We sought to define early determinants of the association between CV disease and LTL in an adolescent population. Methods and Results— One thousand eighty adolescents, aged 13 to 16 years and participating in the Ten Towns Heart Health Study, provided blood samples for DNA extraction and measurement of a range of CV risk factors. LTL was measured by real-time polymerase chain reaction. LTL was inversely associated with age ( P =0.04), longer in females than in males ( P =0.03), and longer in South Asians than in white Europeans ( P =0.01). No associations were found between LTL and traditional CV risk factors. There was a significant and inverse association between LTL and inflammatory markers, including C-reactive protein ( P P =0.001). The associations between LTL and inflammatory markers were not affected by multiple adjustments for behavioral and metabolic factors. Conclusion— High levels of inflammation are associated with shorter LTL from early adolescence; traditional CV risk factors have little association with LTL in adolescence. Inflammation in early life may play a causal role in the adult association between short LTL and CV disease.

Background and Purpose— UK black African-Caribbean adults have higher risks of stroke than white Europeans and have been shown to have increased carotid intima-media thickness (cIMT). We examined whether corresponding ethnic differences in cIMT were apparent in childhood and, if so, whether these could be explained by ethnic differences in cardiovascular risk markers. Methods— We conducted a 2-stage survey of 939 children (208 white European, 240 black African-Caribbean, 258 South Asian, 63 other Asian, 170 other ethnicity), who had a cardiovascular risk assessment and measurements of cIMT at mean ages of 9.8 and 10.8 years, respectively. Results— Black African-Caribbean children had a higher cIMT than white Europeans (mean difference, 0.014 mm; 95% CI, 0.008–0.021 mm; P Conclusions— UK black African-Caribbean children have higher cIMT levels in childhood; the difference is not explained by conventional cardiovascular risk markers. There may be important opportunities for early cardiovascular prevention, particularly in black African-Caribbean children.

CYP2A6 influences smoking uptake in adolescence. Genetic variation in the CHRNA5–CHRNA3 region influences smoking behaviour in adults. However, their combined effects on smoking in adolescence have not been tested to date. We present data on 1450 adolescents from the Ten Towns Heart Health Study (TTHHS) extensively phenotyped for smoking-related traits during adolescence. Single nucleotide polymorphisms from CHRNA5 and CHRNA3 (previously associated with smoking), were typed in our study population, previously genotyped for CYP2A6. Association analyses between each genotype and both smoking status and behavioural markers of smoking were performed. rs16969968 in CHRNA5 was associated both at 13–15 years and 18 years with current smoking amongst adolescents who had tried smoking (OR = 1.82, CI = 1.10–3.01, p = 0.02 at age 13–15; OR = 2.39, CI = 1.37–4.17, p = 0.002 at age 18). No association was found for rs578776 in CHRNA3. The effects of CHRNA5 and CYP2A6 genotypes in TTHHS appeared to be independent, with each approximately doubling the odds of being a regular smoker by age 18 years. CYP2A6 genotype insufficiency increases adolescent likelihood of being a regular smoker but increases later life quitting likelihood and reduces average consumption. In contrast, CHRNA5 genotype, acting recessively, affects smoking similarly in adolescents and older adults. These contrasting actions, in digenic combination, illustrate behavioural genetic complexity.