Showing papers by "John J. Reilly published in 2015"

Objectively measured physical activity and sedentary time in youth: the International children's accelerometry database (ICAD).

Abstract: Physical activity and sedentary behaviour in youth have been reported to vary by sex, age, weight status and country. However, supporting data are often self-reported and/or do not encompass a wide range of ages or geographical locations. This study aimed to describe objectively-measured physical activity and sedentary time patterns in youth. The International Children’s Accelerometry Database (ICAD) consists of ActiGraph accelerometer data from 20 studies in ten countries, processed using common data reduction procedures. Analyses were conducted on 27,637 participants (2.8–18.4 years) who provided at least three days of valid accelerometer data. Linear regression was used to examine associations between age, sex, weight status, country and physical activity outcomes. Boys were less sedentary and more active than girls at all ages. After 5 years of age there was an average cross-sectional decrease of 4.2 % in total physical activity with each additional year of age, due mainly to lower levels of light-intensity physical activity and greater time spent sedentary. Physical activity did not differ by weight status in the youngest children, but from age seven onwards, overweight/obese participants were less active than their normal weight counterparts. Physical activity varied between samples from different countries, with a 15–20 % difference between the highest and lowest countries at age 9–10 and a 26–28 % difference at age 12–13. Physical activity differed between samples from different countries, but the associations between demographic characteristics and physical activity were consistently observed. Further research is needed to explore environmental and sociocultural explanations for these differences.

Impact of eating and drinking on body composition measurements by bioelectrical impedance.

Abstract: Background Bioelectrical impedance analysis would be a more practical tool to measure body composition in clinical settings, dietetic practice and epidemiological studies if patients/subjects did not have to fast before measurements. The present study assessed whether the ingestion of food or drink had any biologically significant effect on bioimpedance measurements and body composition by the foot-to-foot method. Methods Fifty-five healthy adults [30 males and 25 females; mean (SD) age 27.7 (7.1) years; mean (SD)body mass index 24 (3.8) kg m−2] were randomly assigned to a 2-day food trial (high-fat meal or high-carbohydrate meal) or a 2-day drink trial (water or high electrolyte drink). Body composition measurements were carried out in the fasting state, immediately after meal consumption and every 30 min for 2 h by the foot-to-foot single frequency bioimpedance technique. Results Bioimpedance increased significantly after the ingestion of food and fluid, although the changes were small. The electrolyte drink, high-fat and high-carbohydrate meals significantly increased the percentage body fat and fat mass. In all cases, the median percentage changes from baseline were approximately 1% in body fat percentage units. Conclusions Although there were statistically significant changes in body composition estimates after food or drink consumption, these were small and within the imprecision of the impedance technique, and so are unlikely to be of clinical significance. The present study suggests that impedance measures of body fatness in clinical settings do not require strict adherence to fasting, and this should increase the opportunities for clinical application.

Objective measurement of sedentary behavior: impact of non-wear time rules on changes in sedentary time

Abstract: Background: Accelerometry non-wear time rules might affect sedentary time, and the associations with health outcomes such as adiposity. However, the exact effect of different non-wear time rules on sedentary time and reported changes in sedentary time is unknown. This study evaluated the effect of different accelerometry non-wear time rules on sedentary time and changes in sedentary time from age 9–12 years. Methods: Accelerometry data were collected as part of the Gateshead Millennium Birth Cohort study. Participants were 9.3 (±0.4) years at baseline (n= 517) and 12.5 (±0.3) years at follow-up (n= 440). Sedentary time was defined using an accelerometry cut-point of 25 counts per 15 s. Non-wear time was defined using manual data reduction (the reference method) and 10 min, 20 min and 60 min consecutive zeros. Differences between methods were analyzed using repeated measures ANOVA with Bonferroni post-hoc analyses. Results: Mean daily sedentary time at age 9 ranged from 364 min per day to 426 min using the 10 min and 60 min rule, respectively (p< 0.05). At 12 years, mean daily sedentary times ranged from 424 min to 518 min (p< 0.05). Mean changes in daily sedentary time over the three years ranged from 60 min to 93 min using the 10 min and 60 min rule, respectively (p< 0.05). When adjusting for wear time, differences in average sedentary time between methods decreased from 62 min to 27 min (age 9), 95 min to 32 min (age 12) and 33 min to 10 min (changes between 9 to 12 years). Conclusions: Using different non-wear time rules results in significant differences in daily sedentary time and changes in sedentary time. Correcting for wear time appears to be a reasonable approach to limiting these differences and may improve comparability between future studies. Using the 20 min rule, while correcting for wear time, provided the most accurate estimates of sedentary time and changes in sedentary time, compared to the manual reference in 9–12 year-olds.

Evaluation of Actical equations and thresholds to predict physical activity intensity in young children

Abstract: This study examined the validity of current Actical activity energy expenditure (AEE) equations and intensity cut-points in preschoolers using AEE and direct observation as criterion measures. Forty 4–6-year-olds (5.3 ± 1.0 years) completed a ~150-min room calorimeter protocol involving age-appropriate sedentary behaviours (SBs), light intensity physical activities (LPAs) and moderate-to-vigorous intensity physical activities (MVPAs). AEE and/or physical activity intensity were calculated using Actical equations and cut-points by Adolph, Evenson, Pfeiffer and Puyau. Predictive validity was examined using paired sample t-tests. Classification accuracy was evaluated using weighted kappas, sensitivity, specificity and area under the receiver operating characteristic curve. The Pfeiffer equation significantly overestimated AEE during SB and underestimated AEE during LPA (P < 0.0125 for both). There was no significant difference between measured and predicted AEEs during MVPA. The Adolph cut-point show...

Determinants of changes in sedentary time and breaks in sedentary time among 9 and 12 year old children

Abstract: The current study aimed to identify the determinants of objectively measured changes in sedentary time and sedentary fragmentation from age 9- to age 12 years. Data were collected as part of the Gateshead Millennium Birth Cohort study from September 2008 to August 2009 and from January 2012 to November 2012. Participants were 9.3 (± 0.4) years at baseline (n = 508) and 12.5 (± 0.3) years at follow-up (n = 427). Sedentary behaviour was measured using an ActiGraph GT1M accelerometer. Twenty potential determinants were measured, within a socio-ecological model, and tested for their association with changes in sedentary time and the extent to which sedentary behaviour is prolonged or interrupted (fragmentation index). Univariate and multivariate linear regression analyses were conducted. Measurements taken during winter and a greater decrease in moderate-to-vigorous intensity physical activity (MVPA) over time were associated with larger increases in sedentary time (seasonality β: − 3.03; 95% CI: − 4.52, − 1.54; and change in MVPA β: − 1.68; 95% CI: − 1.94, − 1.41). Attendance at sport clubs was associated with smaller increases in sedentary time (− 1.99; − 3.44, − 0.54). Girls showed larger decreases in fragmentation index (− 0.52; − 1.01, − 0.02). Interventions aimed at decreasing the decline in MVPA and increasing/maintaining sport club attendance may prevent the rise in sedentary time as children grow older. In addition, winter could be targeted to prevent an increase in sedentary time and reduction in sedentary fragmentation during this season.

Physical Activity Report Cards: Active Healthy Kids Global Alliance and the Lancet Physical Activity Observatory

Abstract: Tremblay (mtremblay@cheo.on.ca) is with the Healthy Active Living and Obesity Research Group, Children’s Hospital of Eastern Ontario Research Institute, Ottawa, Ontario, Canada. Gonzalez is with the Dept of Public Health, School of Medicine, Universidad de los Andes, Bogota, Colombia. Katzmarzyk is with the Pennington Biomedical Research Center, Baton Rouge, LA. Onywera is with the Dept of Recreation Management and Exercise Science, Kenyatta University, Nairobi, Kenya. Reilly is with the Physical Activity for Health Group, School of Psychological Sciences and Health, University of Strathclyde, Glasgow, Scotland. Tomkinson is with the Alliance for Research in Exercise, Nutrition, and Activity, Sansom Institute for Health Research, University of South Australia, Adelaide, South Australia, Australia. Physical Activity Report Cards: Active Healthy Kids Global Alliance and the Lancet Physical Activity Observatory

Influence of adiposity on health-related quality of life in the Gateshead Millennium Study cohort: longitudinal study at 12 years

Abstract: Objective To examine whether adiposity is associated with an impaired quality of life (an individual9s perception of their life) in general population samples in early adolescence. Design and methods Relationships between a direct measure of adiposity (fat mass index from bioimpedance) and a proxy measure (waist circumference), and a generic (KIDSCREEN-27) and a weight-specific measure of health-related quality of life (HRQoL, Impact of Weight on Quality of Life-Kids (IWQOL-Kids)) were examined in a longitudinal population-based cohort of young adolescents aged 12 years (n=519). The effects of change in adiposity over time (from 7 years and 9 years) were also examined (n=331–445 in longitudinal analyses). Results Impairment in HRQoL was associated with current adiposity but it was not predicted by earlier adiposity. At 12 years, higher adiposity was associated with lower Physical Well-Being on KIDSCREEN-27, and with lower Total Scores on the weight-specific IWQOL-Kids instrument, the latter particularly in girls. Conclusions Health and education professionals need to be aware in their clinical practice that higher adiposity impairs HRQoL in general populations of young adolescents. Further research would be useful to determine whether or not children of primary school age self-reporting lower HRQoL are more likely to develop higher adiposity later in adolescence or early adulthood.

The pandemic of low physical activity in children and adolescents

Abstract: Modern children are fatter, less physically fit (including aerobic fitness) and less physically active than in the recent past. These secular trends have occurred in many countries, but have been described most clearly in Canada

The association between obesity and cognitive function in healthy premenopausal women

Abstract: This poster session discusses the association between obesity and cognitive function in healthy premenopausal women.