Factors in youth physical activity participation : from psychological aspects to environmental correlates

Understanding influences on children\u27s physical activity and how these vary by activity and subgroup, such as age and sex of the child, is important for informing the development of effective and targeted interventions. Two cohort studies were conducted across socioeconomic areas of Melbourne, Australia, between 2001 and 2008 among a combined sample of more than 2,700 children aged 5-6 years and 10-12 years at baseline. Data were collected via surveys, and children wore the Actigraph accelerometer for 8 days. Five individual, 10 social, and 17 physical environmental factors were significantly associated with children\u27s physical activity. Patterns of association varied according to the age and sex of the child and also according to the type of activity. These studies provide some insights into the various levels of influence on children\u27s physical activity. More longitudinal and intervention research is needed to better understand the mechanisms of change in children\u27s physical activity behaviour. <br /

Early decrements in bone density after completion of neoadjuvant chemotherapy in pediatric bone sarcoma patients

<p>Abstract</p> <p>Background</p> <p>Bone mineral density (BMD) accrual during childhood and adolescence is important for attaining peak bone mass. BMD decrements have been reported in survivors of childhood bone sarcomas. However, little is known about the onset and development of bone loss during cancer treatment. The objective of this cross-sectional study was to evaluate BMD in newly diagnosed Ewing's and osteosarcoma patients by means of dual-energy x-ray absorptiometry (DXA) after completion of neoadjuvant chemotherapy.</p> <p>Methods</p> <p>DXA measurements of the lumbar spine (L2-4), both femora and calcanei were performed perioperatively in 46 children and adolescents (mean age: 14.3 years, range: 8.6-21.5 years). Mean <it>Z</it>-scores, areal BMD (g/cm²), calculated volumetric BMD (g/cm³) and bone mineral content (BMC, g) were determined.</p> <p>Results</p> <p>Lumbar spine mean Z-score was -0.14 (95% CI: -0.46 to 0.18), areal BMD was 1.016 g/cm²(95% CI: 0.950 to 1.082) and volumetric BMD was 0.330 g/cm³(95% CI: 0.314 to 0.347) which is comparable to healthy peers. For patients with a lower extremity tumor (n = 36), the difference between the affected and non-affected femoral neck was 12.1% (95% CI: -16.3 to -7.9) in areal BMD. The reduction of BMD was more pronounced in the calcaneus with a difference between the affected and contralateral side of 21.7% (95% CI: -29.3 to -14.0) for areal BMD. Furthermore, significant correlations for femoral and calcaneal DXA measurements were found with Spearman-rho coefficients ranging from ρ = 0.55 to ρ = 0.80.</p> <p>Conclusions</p> <p>The tumor disease located in the lower extremity in combination with offloading recommendations induced diminished BMD values, indicating local osteopenia conditions. However, the results revealed no significant decrements of lumbar spine BMD in pediatric sarcoma patients after completion of neoadjuvant chemotherapy. Nevertheless, it has to be taken into account that bone tumor patients may experience BMD decrements or secondary osteoporosis in later life. Furthermore, the peripheral assessment of BMD in the calcaneus via DXA is a feasible approach to quantify bone loss in the lower extremity in bone sarcoma patients and may serve as an alternative procedure, when the established assessment of femoral BMD is not practicable due to endoprosthetic replacements.</p

Time-course of exercise and its association with 12-month bone changes

<p>Abstract</p> <p>Background</p> <p>Exercise has been shown to have positive effects on bone density and strength. However, knowledge of the time-course of exercise and bone changes is scarce due to lack of methods to quantify and qualify daily physical activity in long-term. The aim was to evaluate the association between exercise intensity at 3, 6 and 12 month intervals and 12-month changes in upper femur areal bone mineral density (aBMD) and mid-femur geometry in healthy premenopausal women.</p> <p>Methods</p> <p>Physical activity was continuously assessed with a waist-worn accelerometer in 35 healthy women (35-40 years) participating in progressive high-impact training. To describe exercise intensity, individual average daily numbers of impacts were calculated at five acceleration levels (range 0.3-9.2 <it>g</it>) during time intervals of 0-3, 0-6, and 0-12 months. Proximal femur aBMD was measured with dual x-ray absorptiometry and mid-femur geometry was evaluated with quantitative computed tomography at the baseline and after 12 months. Physical activity data were correlated with yearly changes in bone density and geometry, and adjusted for confounding factors and impacts at later months of the trial using multivariate analysis.</p> <p>Results</p> <p>Femoral neck aBMD changes were significantly correlated with 6 and 12 months' impact activity at high intensity levels (> 3.9 <it>g</it>, <it>r </it>being up to 0.42). Trochanteric aBMD changes were associated even with first three months of exercise exceeding 1.1 <it>g </it>(<it>r </it>= 0.39-0.59, <it>p </it>< 0.05). Similarly, mid-femoral cortical bone geometry changes were related to even first three months' activity (<it>r </it>= 0.38-0.52, <it>p </it>< 0.05). In multivariate analysis, 0-3 months' activity did not correlate with bone change at any site after adjusting for impacts at later months. Instead, 0-6 months' impacts were significant correlates of 12-month changes in femoral neck and trochanter aBMD, mid-femur bone circumference and cortical bone attenuation even after adjustment. No significant correlations were found at the proximal or distal tibia.</p> <p>Conclusion</p> <p>The number of high acceleration impacts during 6 months of training was positively associated with 12-month bone changes at the femoral neck, trochanter and mid-femur. These results can be utilized when designing feasible training programs to prevent bone loss in premenopausal women.</p> <p>Trial registration</p> <p>Clinical trials.gov NCT00697957</p

Parental education and perception of outdoor playing time for preschoolers

Abstract Aim: The objective of this study was to analyze whether or not socioeconomic positions influence outdoor playtime during the week (WK) and on the weekends (WEND). Methods: The sample consisted of 485 (girls; n=223) healthy preschoolers, aged from 3 to 6 years, enrolled in kindergartens from the metropolitan area of Porto, Portugal. Physical Activity (PA) was assessed for 7 consecutive days with an accelerometer. The time playing outdoors during the WK or the WEND was reported by parents. Anthropometric data (weight and height) was collected following standardized protocols. Socioeconomic position was assessed by Parental Education (PE), according to the Portuguese education system. Results: We found differences in time spent playing outdoors either for the WK or WEND, but not for Total PA (TPA), in both sexes. However, regression analysis showed that after age adjustment, BMI and TPA for both sexes, we only found significant associations between low PE (LPE) and high PE (HPE) groups on WK or WEND. However, we found no statistically significant association for boys on the WK (p=0.06). Conclusion: Our findings suggest that socioeconomic position can influence the children’s time spent in outdoor activities, especially on the weekends. This may have implications for future interventions with this age group

Development and testing of the BONES physical activity survey for young children

<p>Abstract</p> <p>Background</p> <p>Weight-bearing and high intensity physical activities are particularly beneficial for stimulating bone growth in children given that bone responds favorably to mechanical load. While it is important to assess the contribution and impact of weight-bearing physical activity on health outcomes, measurement tools that quantify and provide information on these activities separately from overall physical activity are limited. This study describes the development and evaluation of a pictorial physical activity survey (PAS) that measures children's participation and knowledge of high-intensity, weight-bearing ("bone smart") physical activity.</p> <p>Methods</p> <p>To test reliability, two identical sets of the PAS were administered on the same day to 41 children (mean age 7.1 ± 0.8 years; 63% female) and compared. To test validity, accelerometry data from 40 children (mean age 7.7 ± 0.8 years; 50% female) were compared to data provided by the PAS. Agreements between categorical and ordinal items were assessed with Kappa statistics; agreements between continuous indices were assessed with Spearman's correlation tests.</p> <p>Results</p> <p>The subjects produced reliable results in all 10 physical activity participation items (κ range: 0.36-0.73, all p < 0.05), but less reliable in answering if the physical activities were "bone smart" (κ range: -0.04-0.66). Physical activity indices, including metabolic equivalent time and weight-bearing factors, were significant in test-retest analyses (Spearman's <it>r </it>range: 0.57-0.74, all p < 0.001). Minutes of very vigorous activity from the accelerometer were associated with the self-reported weight-bearing activity, moderate-high, and high activity scores from the PAS (Spearman's <it>r </it>range: 0.47-0.48, all p < 0.01). However, accelerometer counts, counts per minute, and minutes of moderate-vigorous and vigorous activity were not associated with the PAS scores.</p> <p>Conclusions</p> <p>Together, the results of these studies suggest that the PAS has acceptable test-retest reliability, but limited validity for early elementary school children. This survey demonstrates a first step towards developing a questionnaire that measures high intensity, weight-bearing activity in schoolchildren.</p

Eating patterns and overweight in 9- to 10-year-old children in Telemark County, Norway: a cross-sectional study

Background/Objectives: Increasing prevalence of overweight in children is a growing health problem. The aim of this study was to describe the eating patterns of 9-to 10-year-old schoolchildren, and to investigate the relationship between overweight and eating patterns. Subjects/Methods: We recruited 1045 children for a cross-sectional study in Telemark County, Norway. The children&apos;s food, snacking and meal frequencies were reported by their parents using a retrospective food frequency questionnaire. Height and weight were measured by health professionals, and body mass index categories were calculated using international standard cutoff points (International Obesity Task Force values). Complete data were obtained for 924 children. Four distinct eating patterns were identified using principal component analysis. We used multiple logistic regression and calculated odds ratios (ORs) with 95% confidence intervals (CIs) for being overweight, and adjusted for parental characteristics and physical activity levels of the children (aORs). Results: Parental characteristics and physical activity were associated with both obesity and eating patterns. Children adhering to a &apos;junk/convenient&apos; eating pattern had a significantly lower likelihood of being overweight (aOR: 0.6; 95% CI: 0.4, 0.9), whereas children adhering to a &apos;varied Norwegian&apos; or a &apos;dieting&apos; eating pattern had a significantly higher likelihood of being overweight (respective values: aOR: 2.1; 95% CI: 1.3, 3.2; aOR: 2.2; 95% CI: 1.4, 3.4). No association with overweight was seen for a &apos;snacking pattern&apos;. Conclusions: The main finding was that, although family characteristics influenced both the prevalence of overweight and overall dietary behaviour, independent associations were evident between eating patterns and overweight, indicating parental modification of the diets of overweight children

Monitoring activities of teenagers to comprehend their habits: study protocol for a mixed-methods cohort study

Abstract: Background: Efforts to increase physical activity in youth need to consider which activities are most likely to be sustained over time in order to promote lifelong participation in physical activity. The Monitoring Activities of Teenagers to Comprehend their Habits (MATCH) study is a prospective cohort study that uses quantitative and qualitative methods to develop new knowledge on the sustainability of specific physical activities. Methods/design: Eight hundred and forty-three grade 5 and 6 students recruited from 17 elementary schools in New Brunswick, Canada, are followed-up three times per year. At each survey cycle, participants complete self-report questionnaires in their classroom under the supervision of trained data collectors. A sub-sample of 24 physically active students is interviewed annually using a semi-structured interview protocol. Parents (or guardians) complete telephone administered questionnaires every two years, and a health and wellness school audit is completed for each school. Discussion: MATCH will provide a description of the patterns of participation in specific physical activities in youth, and enable identification of the determinants of maintenance, decline, and uptake of participation in each activity. These data will inform the development of interventions that take into account which activities are the most likely to be maintained and why activities are maintained or dropped