The measurement, levels, and correlates of physical activity in a bi-ethnic population of young children

Background: The first five years of life, called the early years is a period of rapid and vital physical, behavioural, emotional and social development. Physical activity (PA) is one of the behaviours which develop during the early years, and high levels of PA during the early years have been shown to be related to multiple health outcomes. The importance of PA of young children (children during the early years) has been highlighted by a number of national governments. In order to better inform future interventions and public health policies, a greater understanding of the correlates and determinants of young children s PA is vital. Previous research has been limited through measurement inconsistencies, and few studies have been conducted within multi-ethnic communities, where many young children in the United Kingdom are born. Thesis Aims: 1) to systematically review published research in order to establish currently known correlates and determinants of PA in the early years and identify gaps within the literature. 2) Calculate an accelerometer wear-time criteria to reliably measure young children s habitual PA. 3) Investigate the validity and test re-test reliability of a new parental proxy reported PA questionnaire. 4) Investigate the levels and correlates of moderate-to-vigorous PA (MVPA) in toddlers (1-3 year olds) from a predominately bi-ethnic and bi-linguistic population. Methods: Aim 1) nine electronic databases were searched to identify previous research which investigated associations between an exposure/variable, and a quantitative measure of PA. Correlates/determinants of total PA (TPA), MVPA and light-intensity PA (LPA) were reported using an ecologic model. Aim 2) to calculate a wear-time criteria for young children a simple stepped process was used whereby statistical tests were run to determine the minimum length of wear for one day, if there were any differences between weekdays and weekend days, and the presence of reactivity. Intra-class correlation models and the Spearman-Brown prophecy formula were used to calculate wear-time reliability. Aim 3) this study was undertaken by 196 parents completing a proxy report questionnaire on their child s PA and sedentary behaviour after seven days of their young child (mean age 3.2 ,SD: 0.8 years) wearing an accelerometer. A total of 156 (79.6%) questionnaires were completed in English and 40 (20.4%) were completed in transliterated Urdu. Of the 196 parents, 109 parents completed the EY-PAQ a second time seven days apart from the first EY-PAQ completion; this was to assess test re-test reliability of MVPA and sedentary time. Validity analysis used all data and data falling with specific proportion boundaries for MVPA (2%-41%) and sedentary time (30%-94%). Reliability was assessed using intra-class correlations (ICC) and validity by Bland Altman plots and rank correlation coefficients. Aim 4) this study was undertaken by conducting a cross-sectional analysis using 24 month olds and their mothers data collected as part of the Born in Bradford (BiB) birth cohort sub-sample study called BiB1000. The outcome variable was daily minutes of MVPA measured by the EY-PAQ. Numerous independent variables covering the layers of an ecological model were selected. Univariate linear regression models accounting for sex, age, language and season were conducted to examine the differences between White British and South Asian children s daily minutes of MVPA and each of the EY-PAQ s domains, and the proportion of time spent in MVPA within each of the EY-PAQ s domains. A series of univariate linear regression analyses were performed to examine and identify correlates of MVPA (for the whole sample, and separately for White British and South Asian children). Significant variables found in univariate analyses were then included in hierarchical multivariable regression models (based upon the ecological model), in order to examine the percentage of variance accounted for in daily minutes of MVPA. Results: Aim 1) The systematic review identified a large volume of published research. All studies took place in high income countries and few studies (6%) were of high quality. A small number of correlates and determinants of TPA were identified. The only correlate of MVPA was sex and no determinants of MVPA or LPA were found. PA correlates/ determinants were relatively consistent between objective and subjective PA measures and few studies investigated correlates of toddlers or between children with White and South Asian ethnicity. Aim 2) No differences in accelerometer-determined time in TPA, MVPA or sedentary time were observed between weekdays and weekend days within this sample of young children. Similarly, there was no evidence of reactivity to accelerometer use. For young children living in Bradford, an accelerometer wear-time of a minimum of six hours on any three days was shown to provide reliable estimates of accelerometer-determined time in TPA, MVPA, and sedentary time. Aim 3) The test re-test reliability of the EY-PAQ was moderate for sedentary time and fair for MVPA. The EY-PAQ had poor agreement with accelerometry with both sedentary time and MVPA before the application of boundaries. Post application of boundaries the EY-PAQ still had poor agreement with accelerometer-determined sedentary time but good agreement for MVPA. Limits of agreement were wide for all variables and language and ethnicity did not confound results. Aim 4) Bradford toddlers were found to be very active and no difference was observed between proxy-reported time spent in MVPA between White British and South Asian children. However, White British toddlers were found to have spent significantly more time in reported MVPA while walking for transport compared to South Asian toddlers; while South Asian toddlers reportedly spent significantly more time of MVPA in the home compared to White British toddlers. Correlate models were only statistically significant when multi-layers of the ecological model were included; and correlates differed for South Asian and White British children. Conclusions: There is a need for more high-quality studies exploring correlates/determinants across all layers of the ecologic model, and research investigating MVPA correlates/determinants of toddlers and between ethnicities is sparse. The work reported within this thesis has produced a reliable wear-time criterion for use to estimate accelerometer-determined PA and sedentary time in young children living in a bi-ethnic community. This criterion can now be used in future accelerometer studies (validation, observational and intervention) and the stepped-process offers researchers a method to derive sample-specific wear time criteria. The EY-PAQ is a promising habitual population-level measure of young children s MVPA from a bi-ethnic community. In situations when objective methods are not possible for measurement of young children s MVPA, the EY-PAQ may be a suitable alternative. Levels of toddlers MVPA did not differ by ethnicity but the contexts and correlates did. Therefore, future interventions should seek to maintain and maximise high levels of toddlers MVPA and tailor interventions by ethnicity. The research conducted within this thesis will inform the development of surveillance systems, interventions and public health polices to improve young children s PA levels, particularly children living in a bi-ethnic community

Reliability and validity of the early years physical activity questionnaire (EY-PAQ)

Measuring physical activity (PA) and sedentary time (ST) in young children (<5 years) is complex. Objective measures have high validity but require specialist expertise, are expensive, and can be burdensome for participants. A proxy-report instrument for young children that accurately measures PA and ST is needed. The aim of this study was to assess the reliability and validity of the Early Years Physical Activity Questionnaire (EY-PAQ). In a setting where English and Urdu are the predominant languages spoken by parents of young children, a sample of 196 parents and their young children (mean age 3.2 ± 0.8 years) from Bradford, UK took part in the study. A total of 156 (79.6%) questionnaires were completed in English and 40 (20.4%) were completed in transliterated Urdu. A total of 109 parents took part in the reliability aspect of the study, which involved completion of the EY-PAQ on two occasions (7.2 days apart; standard deviation (SD) = 1.1). All 196 participants took part in the validity aspect which involved comparison of EY-PAQ scores against accelerometry. Validty anaylsis used all data and data falling with specific MVPA and ST boundaries. Reliability was assessed using intra-class correlations (ICC) and validity by Bland–Altman plots and rank correlation coefficients. The test re-test reliability of the EY-PAQ was moderate for ST (ICC = 0.47) and fair for moderate-to-vigorous physical activity (MVPA)(ICC = 0.35). The EY-PAQ had poor agreement with accelerometer-determined ST (mean difference = −87.5 min·day−1) and good agreement for MVPA (mean difference = 7.1 min·day−1) limits of agreement were wide for all variables. The rank correlation coefficient was non-significant for ST (rho = 0.19) and significant for MVPA (rho = 0.30). The EY-PAQ has comparable validity and reliability to other PA self-report tools and is a promising population-based measure of young children’s habitual MVPA but not ST. In situations when objective methods are not possible for measurement of young children’s MVPA, the EY-PAQ may be a suitable alternative but only if boundaries are applied

ActivPAL-measured sitting levels and patterns in 9-10 year old children from a UK city.

Background: There is insufficient evidence of sitting time in UK children from validated objective measures. This study explored sitting patterns in primary school children from Bradford, UK, using the validated activPAL inclinometer. Methods: Overall, 79 children (9.8 (SD 0.3) years old, 52% boys; 70% South Asian) wore activPALs for 7 days. Total sitting time, sitting time accumulated in different bout lengths, and the proportion of wear time spent in these variables were explored and compared across different periods of the week. Results: Children spent 614 ± 112 (median ± IQR) min/day on school days and 690 ± 150 min/day on weekend days sitting. The proportion of time spent sitting was significantly higher on weekend days compared to school days (mean±SD: 74 ± 10% versus 68 ± 8%,P 30 min sitting bouts (mean±CI: 28 ± 27-33% versus 20 ± 20-22%, P 30 min) sitting bouts (mean±CI: 19 ± 16-22% versus 11 ± 10-14%, P < 0.001). Conclusions: Children spent large proportions of their waking day sitting, often accumulated in prolonged uninterrupted bouts and particularly after school and on weekends. Interventions to reduce sitting time in children are urgently needed

Physical activity, sedentary time, and fatness in a biethnic sample of young children

Purpose: This study aimed to investigate associations of objectively measured physical activity (PA) and sedentary time with adiposity in a predominantly biethnic (South Asian and White British) sample of young children. Methods: The sample included 333 children age 11 months to 5 yr who provided 526 cross-sectional observations for PA and body composition. Total PA volume (vector magnitude counts per minute), daily time at multiple intensity levels (the cumulative time in activity 9500, 91000, 91500, I, 96000 counts per minute), and time spent sedentary (G820 counts per minute), in light PA (820–3907 counts per minute) and in moderate-to-vigorous PA (Q3908 counts per minute) were estimated with triaxial accelerometry. Indicators of adiposity included body mass index, waist circumference, and the sum of subscapular and triceps skinfold thicknesses. Statistical analyses were performed using multilevel regression and isotemporal substitution models adjusted for confounders. Effect modification by ethnicity was examined. Results: There was no evidence for effect modification by ethnicity (P interaction Q 0.13). In the whole sample, the accumulated time spent above 3500 counts per minute (i.e., high light-intensity PA) was inversely associated with the sum of skinfolds (A = j0.60 mm, 95% confidence interval [CI] = j1.19 to j0.021, per 20 minIdj1), and the magnitude of association increased dose dependently with PA intensity (peaking for time spent 96000 counts per minute = j1.57 mm, 95% CI = j3.01 to j0.12, per 20 minIdj1). The substitution of 20 minIdj1 of sedentary time with moderate-to-vigorous PA was associated with a lower sum of skinfolds (j0.77 mm, 95% CI = j1.46 to j0.084). Conclusions: High light-intensity PA appears to be beneficial for body composition in young South Asian and White British children, but higher-intensity PA is more advantageous

Reducing children's classroom sitting time using sit-to-stand desks: findings from pilot studies in UK and Australian primary schools.

BACKGROUND: This research examined the influence of sit-to-stand desks on classroom sitting time in primary school children. METHODS: Pilot controlled trials with similar intervention strategies were conducted in primary schools in Melbourne, Australia, and Bradford, UK. Sit-to-stand desks replaced all standard desks in the Australian intervention classroom. Six sit-to-stand desks replaced a bank of standard desks in the UK intervention classroom. Children were exposed to the sit-to-stand desks for 9-10 weeks. Control classrooms retained their normal seated desks. Classroom sitting time was measured at baseline and follow-up using the activPAL3 inclinometer. RESULTS: Thirty UK and 44 Australian children provided valid activPAL data at baseline and follow-up. The proportion of time spent sitting in class decreased significantly at follow-up in both intervention groups (UK: -9.8 ± 16.5% [-52.4 ± 66.6 min/day]; Australian: -9.4 ± 10% [-43.7 ± 29.9 min/day]). No significant changes in classroom sitting time were observed in the UK control group, while a significant reduction was observed in the Australian control group (-5.9 ± 11.7% [-28.2 ± 28.3 min/day]). CONCLUSIONS: Irrespective of implementation, incorporating sit-to-stand desks into classrooms appears to be an effective way of reducing classroom sitting in this diverse sample of children. Longer term efficacy trials are needed to determine effects on children's health and learning

Socio-demographic and behavioural risk factors associated with the high prevalence of overweight and obesity in Portuguese children

Objectives: Childhood obesity is a public health concern in Portugal. Socio-demographic and behavioral factors are highly associated with obesity but are not clearly understood. This article aims to update the prevalence of overweight and obesity in Portuguese children and to explore the influence and risks of socio-demographic factors and behavioral factors. Methods: A cross-sectional study of Portuguese children aged 3–10 years from all 18 mainland districts took place between March 2009 and January 2010. The sample was composed by 17,136 children, 3–10 years of age (8,455 boys; 8,681 girls). Height, weight, and other anthropometric measurements were obtained by trained technicians. Body mass index (BMI) was calculated along with other anthropometric variables. Data analyses took place between April and September 2012. The overweight/obesity classification was established by age-and sex-specific BMI cut-off points as defined by the International obesity task force (IOTF). Parents completed questionnaires about socio-demographic and behavioral characteristics of the family. Results: Almost 28% of the Portuguese children were overweight or obese (19.7% overweight; 8.2% obese). Prevalence was greater in girls than in boys. Logistic regression models found that the odds of childhood obesity were significantly affected by biological, socio-demographic, and behavioral factors. Conclusions: The protective factors against childhood overweight/obesity in this sample of Portuguese children are: (i) being male; (ii) having been breastfeed; (iii) having been born from mothers who did not smoke during pregnancy; (iv) engaging in little sedentary behaviors (TV, PC, and playing electronic games); (iv) performing at least 1 h of moderate physical activity every day; and (v) having parents with higher educational levels who also have their BMI within the healthy ranges

Inter-rater reliability sensitivity of scoring.

AimAssess whether school-based teacher-led screening is effective at identifying children with motor difficulties.MethodsTeachers tested 217 children aged between 5 and 11 years old, after a one hour training session, using a freely available tool (FUNMOVES). Four classes (n = 91) were scored by both researchers and teachers to evaluate inter-rater reliability. Researchers assessed 22 children using the Movement Assessment Battery for Children (MABC-2; considered to be the ‘gold standard’ in Europe for use as part of the diagnostic process for Developmental Coordination Disorder) to assess concurrent and predictive validity.ResultsInter-rater reliability for all individual activities within FUNMOVES ranged from 0.85–0.97 (unweighted Kappa; with 95%CI ranging from 0.77–1). For total score this was lower (κ = 0.76, 95%CI = 0.68–0.84), however when incorporating linear weighting, this improved (κ = 0.94, 95%CI = 0.89–0.99). When evaluating FUNMOVES total score against the MABC-2 total score, the specificity (1, 95%CI = 0.63–1) and positive predictive value (1; 95%CI = 0.68–1) of FUNMOVES were high, whereas sensitivity (0.57, 95%CI = 0.29–0.82) and negative predictive values (0.57, 95%CI = 0.42–0.71) were moderate. Evaluating only MABC-2 subscales which are directly related to fundamental movement skills (Aiming & Catching, and Balance) improved these values to 0.89 (95%CI = 0.52–1) and 0.93 (95%CI = 0.67–0.99) respectively.InterpretationTeacher-led screening of fundamental movement skills (via FUNMOVES) is an effective method of identifying children with motor difficulties. Such universal screening in schools has the potential to identify movement difficulties and enable earlier intervention than the current norm.</div

Concurrent and predictive validity analyses.

AimAssess whether school-based teacher-led screening is effective at identifying children with motor difficulties.MethodsTeachers tested 217 children aged between 5 and 11 years old, after a one hour training session, using a freely available tool (FUNMOVES). Four classes (n = 91) were scored by both researchers and teachers to evaluate inter-rater reliability. Researchers assessed 22 children using the Movement Assessment Battery for Children (MABC-2; considered to be the ‘gold standard’ in Europe for use as part of the diagnostic process for Developmental Coordination Disorder) to assess concurrent and predictive validity.ResultsInter-rater reliability for all individual activities within FUNMOVES ranged from 0.85–0.97 (unweighted Kappa; with 95%CI ranging from 0.77–1). For total score this was lower (κ = 0.76, 95%CI = 0.68–0.84), however when incorporating linear weighting, this improved (κ = 0.94, 95%CI = 0.89–0.99). When evaluating FUNMOVES total score against the MABC-2 total score, the specificity (1, 95%CI = 0.63–1) and positive predictive value (1; 95%CI = 0.68–1) of FUNMOVES were high, whereas sensitivity (0.57, 95%CI = 0.29–0.82) and negative predictive values (0.57, 95%CI = 0.42–0.71) were moderate. Evaluating only MABC-2 subscales which are directly related to fundamental movement skills (Aiming & Catching, and Balance) improved these values to 0.89 (95%CI = 0.52–1) and 0.93 (95%CI = 0.67–0.99) respectively.InterpretationTeacher-led screening of fundamental movement skills (via FUNMOVES) is an effective method of identifying children with motor difficulties. Such universal screening in schools has the potential to identify movement difficulties and enable earlier intervention than the current norm.</div

True positives, true negatives, false positives and false negatives.

True positives, true negatives, false positives and false negatives.</p

Concurrent and predictive validity for FUNMOVES.

AimAssess whether school-based teacher-led screening is effective at identifying children with motor difficulties.MethodsTeachers tested 217 children aged between 5 and 11 years old, after a one hour training session, using a freely available tool (FUNMOVES). Four classes (n = 91) were scored by both researchers and teachers to evaluate inter-rater reliability. Researchers assessed 22 children using the Movement Assessment Battery for Children (MABC-2; considered to be the ‘gold standard’ in Europe for use as part of the diagnostic process for Developmental Coordination Disorder) to assess concurrent and predictive validity.ResultsInter-rater reliability for all individual activities within FUNMOVES ranged from 0.85–0.97 (unweighted Kappa; with 95%CI ranging from 0.77–1). For total score this was lower (κ = 0.76, 95%CI = 0.68–0.84), however when incorporating linear weighting, this improved (κ = 0.94, 95%CI = 0.89–0.99). When evaluating FUNMOVES total score against the MABC-2 total score, the specificity (1, 95%CI = 0.63–1) and positive predictive value (1; 95%CI = 0.68–1) of FUNMOVES were high, whereas sensitivity (0.57, 95%CI = 0.29–0.82) and negative predictive values (0.57, 95%CI = 0.42–0.71) were moderate. Evaluating only MABC-2 subscales which are directly related to fundamental movement skills (Aiming & Catching, and Balance) improved these values to 0.89 (95%CI = 0.52–1) and 0.93 (95%CI = 0.67–0.99) respectively.InterpretationTeacher-led screening of fundamental movement skills (via FUNMOVES) is an effective method of identifying children with motor difficulties. Such universal screening in schools has the potential to identify movement difficulties and enable earlier intervention than the current norm.</div