Associations of extracurricular physical activity patterns and body composition components in a multi-ethnic population of UK children (the Size and Lung Function in Children study): a multilevel modelling analysis.

BACKGROUND: Body Mass Index (BMI) is a common outcome when assessing associations between childhood overweight and obesity and physical activity patterns. However, the fat and fat-free components of BMI, measured by the Fat Mass Index (FMI) and Fat-Free Mass Index (FFMI), may show contrasting associations with physical activity, while ethnic groups may vary in both physical activity patterns and body composition. Body composition must therefore be evaluated when assessing the associations between childhood overweight and obesity and physical activity in multi-ethnic populations. METHODS: This cross-sectional study investigated associations of BMI, FMI and FFMI z-scores with extracurricular physical activity for 2171 London primary schoolchildren (aged 5-11 years) of black, South Asian and white/other ethnicity. Multilevel mixed-effects ordered logistic modelling was used, adjusting for age, sex and family and neighbourhood socioeconomic status as potential confounders. RESULTS: Controlling for ethnicity and individual, family and neighbourhood socioeconomic confounders, actively commuting children had significantly lower Odds Ratios for being in high BMI (Odds Ratio (OR) = 0.678; 95 % Confidence Interval (CI) = 0.531 - 0.865; p - value = 0.002) and FMI z-score groups (OR = 0.679; 95 % CI = 0.499 - 0.922; p = 0.013), but not FFMI z-score groups, than passive commuters. Children doing sports less than once a week had lower Odds Ratios for being in high BMI (OR = 0.435; 95 % CI = 0.236 - 0.802; p = 0.008) and FFMI (OR = 0.455; 95 % CI = 0.214 - 0.969; p = .041) z-score categories compared to daily active children. Differences in FMI between groups did not reach the significance threshold. A trend towards statistical significance was obtained whereby children's complete inactivity was associated with higher odds for being in higher BMI (OR = 2.222 : 95 % CI = 0.977 - 5.052; p = .057) and FMI z-score groups (OR = 2.485 : 95 % CI = 0.961 - 6.429; p = .060). FFMI z-scores did not show a similar trend with complete inactivity. CONCLUSIONS: Active commuting was objectively associated with lower adiposity, while more frequent extracurricular sports participation was correlated with greater fat-free mass accretion. These relationships were independent of ethnicity and individual, family or neighbourhood socioeconomic confounding factors.Wellcome Trust (WT094129MA) Gonville and Caius College, University of Cambridge (Gonville Scholarship

Associations of the objective built environment along the route to school with children's modes of commuting: A multilevel modelling analysis (the SLIC study).

As active commuting levels continue to decline among primary schoolchildren, evidence about which built environmental characteristics influence walking or cycling to school remains inconclusive and is strongly context-dependent. This study aimed to identify the objective built environmental drivers of, and barriers to, active commuting to school for a multi-ethnic sample of 1,889 healthy primary schoolchildren (aged 5-11) in London, UK. Using cross-sectional multilevel ordered logistic regression modelling, supported by the spatial exploration of built environmental characteristics through cartography, the objective built environment was shown to be strongly implicated in children's commuting behaviour. In line with earlier research, proximity to school emerged as the prime variable associated with the choice for active commuting. However, other elements of the urban form were also significantly associated with children's use of active or passive modes of transport. High levels of accidents, crime and air pollution along the route to school were independently correlated with a lower likelihood of children walking or cycling to school. Higher average and minimum walkability and higher average densities of convenience stores along the way were independently linked to higher odds of active commuting. The significance of the relations for crime, air pollution and walkability disappeared in the fully-adjusted model including all built environmental variables. In contrast, relationships with proximity, traffic danger and the food environment were maintained in this comprehensive model. Black children, pupils with obesity, younger participants and those from high socioeconomic families were less likely to actively commute to school. There is thus a particular need to ensure that roads with high volumes of actively commuting children are kept safe and clean, and children's exposure to unhealthy food options along the way is limited. Moreover, as short commuting distances are strongly correlated with walking or cycling, providing high-quality education near residential areas might incite active transport to school

Development and validation of a prediction model for fat mass in children and adolescents: Meta-analysis using individual participant data

© Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to. 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\u27s 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

Body-mass index adjustments to increase the validity of body fatness assessment in UK black African and South Asian children: a cross-sectional calibration study

BackgroundExcess 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.MethodsFour 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.FindingsThe FMI derived for this study population and used in analyses was fat mass/height5, 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/m2 (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\u3c0·0001 boys and girls). BMI adjustments therefore varied by age-group and FMI level, between −0·24 and −2·84 kg/m2 for boys and between −0·22 and −2·86 kg/m2 for girls for unadjusted BMI values of 13 kg/m2 in 10–12 year-olds and 25 kg/m2 in 4–6 year-olds, respectively.InterpretationBMI 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.FundingThis 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\u27 Charity

Impact of Ethnicity and Extreme Prematurity on Infant Pulmonary Function

Summary. The impact of birth before 27 completed weeks of gestation on infant pulmonary function (PF) was explored in a multi-ethnic population in comparison to more mature preterm controls (PTC) and healthy fullterm infants. Plethysmographic lung volume (FRC pleth ) and forced expired volume (FEV 0.5 .44] z-scores, P < 0.001), as was forced vital capacity (FVC) but there were no significant differences in FRC pleth or FEV 0.5 /FVC ratio. FEV 0.5 , FVC, and FEV 0.5 /FVC were significantly lower in both preterm groups when compared with fullterm controls. On multivariable analyses of the combined preterm dataset: FEV 0.5 at $1 year was 0.11 [0.05; 0.17] z-scores higher/week GA, and 1.28 (0.49; 2.08) z-scores lower in EP infants with prior BPD. Among nonwhite preterm infants, FEV 0.5 was 0.70 (0.17; 1.24) z-scores lower, with similar reductions in FVC, such that there were no ethnic differences in FEV 0.5 /FVC. Similar ethnic differences were observed among fullterm infants. These results confirm the negative impact of preterm birth on subsequent lung development, especially following a diagnosis of BPD, and emphasize the importance of taking ethnic background into account when interpreting results during infancy as in older subjects

Pulmonary function deficits in newborn screened infants with cystic fibrosis managed with standard UK care are mild and transient

With the advent of novel designer molecules for cystic fibrosis (CF) treatment, there is huge need for early-life clinical trial outcomes, such as infant lung function (ILF). We investigated the degree and tracking of ILF abnormality during the first 2 years of life in CF newborn screened infants. Forced expiratory volume in 0.5 s (FEV₀.₅), lung clearance index (LCI) and plethysmographic functional residual capacity were measured at ∼3 months, 1 year and 2 years in 62 infants with CF and 34 controls. By 2 years there was no significant difference in FEV₀.₅ z-score between CF and controls, whereas mean LCI z-score was 0.81 (95% CI 0.45–1.17) higher in CF. However, there was no significant association between LCI z-score at 2 years with either 3-month or 1-year results. Despite minimal average group changes in any ILF outcome during the second year of life, marked within-subject changes occurred. No child had abnormal LCI or FEV₀.₅ on all test occasions, precluding the ability to identify “high-risk” infants in early life. In conclusion, changes in lung function are mild and transient during the first 2 years of life in newborn screened infants with CF when managed according to a standardised UK treatment protocol. Their potential role in tracking disease to later childhood will be ascertained by ongoing follow-up

OBILJEŽJA POČINITELJA NASILNIČKIH DELIKATA NA PODRUČJU PRIMORSKO-GORANSKE ŽUPANIJE OBZIROM NA POVRAT

Availability of sophisticated statistical modelling for developing robust reference equations has improved interpretation of lung function results. In 2012, the Global Lung function Initiative(GLI) published the first global all-age, multi-ethnic reference equations for spirometry but these lacked equations for those originating from the Indian subcontinent (South-Asians). The aims of this study were to assess the extent to which existing GLI-ethnic adjustments might fit South-Asian paediatric spirometry data, assess any similarities and discrepancies between South-Asian datasets and explore the feasibility of deriving a suitable South-Asian GLI-adjustment. Methods: Spirometry datasets from South-Asian children were collated from four centres in India and five within the UK. Records with transcription errors, missing values for height or spirometry, and implausible values were excluded(n=110). Results: Following exclusions, cross-sectional data were available from 8,124 children (56.3% male; 5-17 years). When compared with GLI-predicted values from White Europeans, forced expired volume in 1s (FEV1) and forced vital capacity (FVC) in South-Asian children were on average 15% lower, ranging from 4-19% between centres. By contrast, proportional reductions in FEV1 and FVC within all but two datasets meant that the FEV1/FVC ratio remained independent of ethnicity. The ‘GLI-Other’ equation fitted data from North India reasonably well while ‘GLI-Black’ equations provided a better approximation for South-Asian data than the ‘GLI-White’ equation. However, marked discrepancies in the mean lung function z-scores between centres especially when examined according to socio-economic conditions precluded derivation of a single South-Asian GLI-adjustment. Conclusion: Until improved and more robust prediction equations can be derived, we recommend the use of ‘GLI-Black’ equations for interpreting most South-Asian data, although ‘GLI-Other’ may be more appropriate for North Indian data. Prospective data collection using standardised protocols to explore potential sources of variation due to socio-economic circumstances, secular changes in growth/predictors of lung function and ethnicities within the South-Asian classification are urgently required