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

Violin plots and boxplots showing the estimation bias of model 4 across the whole test group (top left), by sex (top right), by age tertiles (bottom left) and BMI categories (bottom right).

<p>Violin plots and boxplots showing the estimation bias of model 4 across the whole test group (top left), by sex (top right), by age tertiles (bottom left) and BMI categories (bottom right).</p

Performance of the four models of wrist acceleration.

<p>Explained variance shown is between-individual explained variance from ANOVA repeated measures.</p

Summary statistics of the cohort, provided separately for the training and test datasets, by sex.

<p>Summary statistics of the cohort, provided separately for the training and test datasets, by sex.</p

Example of simultaneous PAEE and wrist acceleration signal over 5 days.

<p>Example of simultaneous PAEE and wrist acceleration signal over 5 days.</p

Forest plot showing the beta point estimates and their respective confidence intervals of the effect size of PAEE on BMI.

<p>Forest plot showing the beta point estimates and their respective confidence intervals of the effect size of PAEE on BMI.</p

Additional file 1 of Prospective associations between changes in physical activity and sedentary time and subsequent lean muscle mass in older English adults: the EPIC-Norfolk cohort study

Additional file 1: Table S1. Participant characteristics for those included versus excluded

Additional file 1: of Development and feasibility of a wearable infant wrist band for the objective measurement of physical activity using accelerometery

Acceptability Questionnaire. (PDF 67 kb

Characteristics of the study sample of 1727 participants from the MRC National Survey of Health and Development at age 60–64.

<p>Data are means (SD) and <i>n</i> (%).</p><p>^aGrip strength: men = 793, women = 819; chair rise speed: men = 785, women = 832; standing balance time: men = 803, women = 848; TUG time: men = 765, women = 824;</p><p>^bHeight: n = 834 for men; weight: n = 835 for men and n = 889 for women;</p><p>^cMen = 792 and women = 845;</p><p>^dMen = 833 and women = 886;</p><p>^eMen = 761 and women = 817;</p><p>^fMen = 835 and women = 888.</p><p>Note: Sedentary time was defined as a MET value of <1.5 in accordance with current convention [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0126465#pone.0126465.ref030" target="_blank">30</a>] and MVPA as ≥3.0 METs using an individualised estimate of RMR to define one MET [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0126465#pone.0126465.ref031" target="_blank">31</a>].</p><p>Characteristics of the study sample of 1727 participants from the MRC National Survey of Health and Development at age 60–64.</p

The percentage (%) of participants, (n^§ = 2188) reporting sport and exercise activities on a regular basis^‡, by gender.

<p>^§ Percentages reported are based on available n for each specific activity; ^‡‘report of weekly participation in ‘x’ activity of minimum duration, 30 minutes per episode’. ^*p<0.05; ^‡p<0.10: test of gender difference. <i>Note</i>: No difference by gender existed for exercises with weights and conditioning exercises either in the last year or report of regular participation; N's were not robust to examine football, horse-riding, cricket, ice-skating, martial arts, and netball by gender due to low number of participants reporting these activities. Activity order was determined by the most frequent activity in both genders combined. Top ten most frequently reported activities by gender (where ‘1’ indicates most frequently reported activity): <i>Men</i>: 1) walking for pleasure, 2) golfing, 3) floor exercises, 4) backpacking/hill-walking, 5) conditioning exercises, 6) cycling, 7) swimming, 8) exercises with weights, 9) fishing and 10) snooker. <i>Women</i>: 1) walking for pleasure, 2) floor exercises, 3) swimming, 4) conditioning exercises, 5) aerobics, 6) dancing, 7) backpacking/hill-walking, 8) exercises with weights, 9) golfing and 10) cycling.</p