Prevalence, trajectories, and determinants of television viewing time in an ethnically diverse sample of young children from the UK

BACKGROUND: Excessive screen viewing in early childhood is associated with poor physical and psycho-social health and poor cognitive development. This study aimed to understand the prevalence, trajectory and determinants of television viewing time in early childhood to inform intervention development. METHODS: In this prospective longitudinal study, mothers of 1558 children (589 white British, 757 Pakistani heritage, 212 other ethnicities) completed questionnaires when their children were approximately 6, 12, 18, 24 and 36 months old. Mothers answered questions about their own and their child's TV-time. TV-time trajectories were estimated by linear longitudinal multilevel modeling, potential determinants were considered in models. RESULTS: The modelled trajectory estimated that 75% of children aged 12 months exceeded guidelines of zero screen-time. At 12 months of age an accelerated increase in TV-time was observed (2 h/day by 30 months old). For every hour of mothers' TV-time and every hour the TV was on in the home, children's TV-time was 8 min and 1 min higher respectively at 6 months old (P < 0.05), and 15 min and 3 min higher respectively at 36 months old (P < 0.05). Children whose mothers did not agree that it was important their child did not watch too much TV, had 17 min more TV-time than their counterparts (P < 0.05). Children of first time mothers had 6 min more TV-time (P < 0.05). At 12 months of age, children of mothers experiencing stress watched 8 min more TV (P < 0.05). By 36 months, children of Pakistani heritage mothers had 22 min more TV-time than those of white British mothers (P < 0.05), and an additional 35 min of TV-time if their mother was not born in the UK (P < 0.05). CONCLUSIONS: High levels of TV-time were prevalent. Intervention developers should consider targeting interventions before 12 months of age. Modifiable determinants included mothers' own TV-time, the time the television is on in the home and mothers' attitude towards child TV-time. These behaviours may be key components to address in interventions for parents. Mothers experiencing stress, first time mothers, and Pakistani heritage mothers (particularly those born outside of the UK), may be priority groups for intervention

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

Magnitude and determinants of change in objectively-measured physical activity, sedentary time and sleep duration from ages 15 to 17.5y in UK adolescents: the ROOTS study.

BACKGROUND: Self-reported physical activity (PA) and sleep duration (SLP) change markedly throughout adolescence. We sought to quantify changes in objectively-measured PA, sedentary time (ST) and SLP through adolescence, and to investigate baseline body composition and baseline activity levels as determinants of change. METHODS: Individually calibrated combined heart rate and movement sensing was used to estimate PA energy expenditure (PAEE), SLP, daily ST and time in light (LPA), moderate (MPA), vigorous (VPA), and moderate-to-vigorous physical activity (MVPA) in 144 adolescents (50% boys) of mean age 15.1(±0.3)y at baseline and 17.5(±0.3)y at follow-up. Changes in PA (ΔPA), ST (ΔST) and SLP (ΔSLP) were calculated as follow-up minus baseline values. Waist circumference (WC) was measured at baseline and follow-up, as was fat mass index (FMI) and fat-free mass index (FFMI) by a pooled estimation method including bio-impedance. Comparison of baseline and follow-up activity was made by mixed-model ANOVA. Linear regression adjusted for baseline demographics, total and weekend hours of monitor wear time and the seasons of activity measurements, was used to investigate baseline body composition as determinants of ΔPA, ΔST and ΔSLP. A further model adjusted for baseline of the outcome assessed baseline activity as a predictor of behaviour change, and investigated associations for baseline body composition independent of the baseline level of the outcome. RESULTS: From baseline to follow-up levels of MPA and VPA declined (p ≤ 0.039). The annual decline in MVPA was equivalent to -4.5 and -3.0 min/d in boys and girls, respectively. Baseline FMI, FFMI and WC were positively associated with ΔLPA and negatively associated with ΔST in boys when adjusted for baseline of the outcome (p ≤ 0.037 for all). SLP increased from baseline to follow-up (p = 0.004) but ΔSLP was not associated with baseline body composition (p ≥ 0.13). For all variables, higher baseline levels were associated with greater declines over time (p ≤ 0.003). CONCLUSIONS: Levels of higher-intensity PA decline from mid-to-late adolescence, whereas the duration of sleep increases. Changes in LPA and ST may be associated with baseline body composition, but the baseline level of the outcome is consistently the strongest predictor of changes in adolescent activity.This work was supported by the Medical Research Council [Unit Programme grant numbers MC_U106179476 and MC_UU_12015/3], the Wellcome Trust [grant 074296/ Z/04/Z] and the British Heart Foundation [grant FS/12/58/29709 to KWi].This is the final version. It was first published by Springer at http://link.springer.com/article/10.1186%2Fs12966-015-0222-4

Prospective associations between sedentary time, sleep duration and adiposity in adolescents.

OBJECTIVE: The objective of this study was to investigate whether objectively measured sedentary time and sleep duration are associated with changes in adiposity from mid- to late adolescence. METHODS: Students (n = 504, 42% boys) were recruited from schools in Cambridgeshire, UK. At baseline (mean age 15.0 ± 0.3 years), sedentary time was objectively measured by ≥3 days of combined heart rate and movement sensing. Concurrently, sleep duration was measured by combined sensing in conjunction with self-reported bed times. Fat mass index (FMI; kg/m(2)) was estimated at baseline and follow-up (17.5 ± 0.3 years) by anthropometry and bioelectrical impedance. FMI change (ΔFMI) was calculated by subtracting the baseline from follow-up values. Linear regression models adjusted for basic demographics, moderate-to-vigorous physical activity (MVPA), and depressive symptoms were used to investigate associations of sedentary time and sleep duration (mutually adjusted for one another) with ΔFMI. RESULTS: FMI increased by 0.5 and 0.6 kg/m(2) in boys and girls, respectively, but there was no association between sedentary time and ΔFMI in either gender (p ≥ 0.087), and no association between sleep duration and ΔFMI in girls (p ≥ 0.61). In boys, each additional hour of baseline sleep significantly reduced the ΔFMI by 0.13 kg/m(2) (p = 0.049), but there was little evidence for this association after adjusting for MVPA and depressive symptoms (p = 0.15). CONCLUSIONS: Sedentary time may not determine changes in adiposity from mid- to late adolescence, nor may sleep duration in girls. However, sleep length may be inversely associated with adiposity gain in boys, depending on whether the relationship is confounded or mediated by MVPA and depression.This work was supported by the Medical Research Council (Unit Programme number MC_UU_12015/3), the Wellcome Trust (grant 074296/Z/04/Z) and the British Heart Foundation (grant FS/12/58/29709 to KW).This is the final version of the article. It first appeared from Elsevier via http://dx.doi.org/10.1016/j.sleep.2015.02.53

Is small size at birth associated with early childhood morbidity in white British and Pakistani origin UK children aged 0-3? Findings from the born in Bradford cohort study

Abstract Background Low birthweight is associated with increased infant morbidity, poorer developmental outcomes and risk of adult disease and its prevention remains a public health priority. South Asian children are more likely to be born small and there is some debate around whether this is a normal phenomenon within this population or whether they have a greater risk of morbidity. We examined the association between small size at birth and morbidity in White British and Pakistani origin children aged 0–3 participating in the Born in Bradford cohort study. Methods We included 4119 White British and 4731 Pakistani origin children and examined health service use (General Practitioner (GP) consultations, the most common prescribing categories (analgesics, antibiotics, bronchodilators), emergency and elective hospital episodes) as markers of morbidity, in children born small defined as: (i) low birthweight (< 2500 g) (ii) small for gestational age (SGA) using customised birth charts. We used negative binomial regression models to predict the adjusted incidence of morbidity markers. Results 8.7% of Pakistani and 5% of White British children were born with a low birthweight (< 2500 g). Using customised charts, these proportions were 15.3 and 6.2% respectively. Children born small in both groups irrespective of the criteria used, generally had a higher rate of episodes for morbidity markers compared to normal weight children. Incidence of GP consultations (IRR 1.48 (95% CI 1.27, 1.73) to 1.55 (95% CI 1.36, 1.76) depending on birthweight category), analgesic (IRR 1.76 (95% CI 1.37, 2.25) to 2.31 (95% CI 2.19, 2.45) and antibiotic prescriptions (IRR 1.13 (95% CI 0.08, 1.46) to 1.38 (95% CI 1.30, 1.48) and emergency hospital episodes (IRR 1.20 (95% CI 1.06, 1.36) to 1.46 (95% CI 0.92, 2.32), was higher in Pakistani origin children with either a low or normal birthweight. Conclusion Being born small is associated with greater morbidity estimated by use of health services, in both White British and Pakistani origin children underlining the importance of public health policy to reduce low birthweight. Pakistani origin children access health services more frequently than White British children irrespective of birthweight and this has implications for health service planning in areas with South Asian populations

Static disorder in a perovskite mixed-valence metal–organic framework

ariable-temperature and variable-pressure single-crystal diffraction studies are carried out on a mixed-valence perovskite dimethylammonium (DMA) iron formate compound, with the formula [(DMA3)(H2O)][FeII3FeIII(HCOO)12], in order to investigate potential electric ordering of the DMA cation from its fourfold type of dynamic disorder at ambient conditions. Mössbauer spectroscopy is additionally carried out at ambient conditions to confirm the presence and ratio of Fe2+ and Fe3+ cations. Below 200 K, a dynamic to static disorder of the DMA cation is observed, while the crystal symmetry and iron formate framework structure remain the same. Upon application of pressure, however, a phase transition occurs that lowers the symmetry above 3.3 GPa. This work highlights the further chemical modifications that are possible within the dimethylammonium metal formates family, i.e. doping upon the A-site with neutral molecules, leading to additional opportunities to tune their physical properties

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

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

Enhancing the chemical flexibility of hybrid perovskites by introducing divalent ligands

Herein we report the synthesis and structures of [(CH$_3$)$_2$NH$_2$]Er(HCO$_2$)$_2$(C$_2$O$_4$) and [(NH$_2$)$_3$C]Er(HCO$_2$)$_2$(C$_2$O$_4$), in which the inclusion of divalent oxalate ligands allows for the exclusive incorporation of A$^+$ and B$^{3+}$ cations in an ABX$_3$ hybrid perovskite structure for the first time. We rationalise the observed thermal expansion of these materials, including negative thermal expansion, and find evidence for weak antiferromagnetic coupling in [(CH$_3$)$_2$NH$_2$]Er(HCO$_2$)$_2$(C$_2$O$_4$)

Alginate inhibits iron absorption from ferrous gluconate in a randomized controlled trial and reduces iron uptake into Caco-2 cells

Previous in vitro results indicated that alginate beads might be a useful vehicle for food iron fortification. A human study was undertaken to test the hypothesis that alginate enhances iron absorption. A randomised, single blinded, cross-over trial was carried out in which iron absorption was measured from serum iron appearance after a test meal. Overnight-fasted volunteers (n=15) were given a test meal of 200g cola-flavoured jelly plus 21 mg iron as ferrous gluconate, either in alginate beads mixed into the jelly or in a capsule. Iron absorption was lower from the alginate beads than from ferrous gluconate (8.5% and 12.6% respectively, p=0.003). Sub-group B (n=9) consumed the test meals together with 600 mg calcium to determine whether alginate modified the inhibitory effect of calcium. Calcium reduced iron absorption from ferrous gluconate by 51%, from 11.5% to 5.6% (p=0.014), and from alginate beads by 37%, from 8.3% to 5.2% (p=0.009). In vitro studies using Caco-2 cells were designed to explore the reasons for the difference between the previous in vitro findings and the human study; confirmed the inhibitory effect of alginate. Beads similar to those used in the human study were subjected to simulated gastrointestinal digestion, with and without cola jelly, and the digestate applied to Caco-2 cells. Both alginate and cola jelly significantly reduced iron uptake into the cells, by 34% (p=0.009) and 35% (p=0.003) respectively. The combination of cola jelly and calcium produced a very low ferritin response, 16.5% (p<0.001) of that observed with ferrous gluconate alone. The results of these studies demonstrate that alginate beads are not a useful delivery system for soluble salts of iron for the purpose of food fortification