Showing papers by "Gregory J. Welk published in 2009"

Fiabilidad y validez del cuestionario de actividad física paq-a en adolescentes españoles

Abstract: Reliability and Validity of the PAQ-A Questionnaire to Assess Physical Activity in Spanish Adolescents Background: Questionnaires are feasible instruments to assess physical activity (PA) in large samples. The aim of the current study was to evaluate the reliability and validity of the PAQ-A questionnaire in Spanish adolescents using the measurement of PA by accelerometer as criterion. Methods: In a sample of 82 adolescents, aged 12 to 17 years, 1week PAQ-A test-retest was administered. Reliability was analyzed by the Intraclass Correlation Coefficient (ICC) and the internal consistency by the Cronbach’s α Coefficient. Two hundred thirty-two adolescents, aged 13-17 years, completed the PAQ-A and wore the ActiGraph GT1M accelerometer during 7-days. The PAQ-A was compared against total PA and moderate to vigorous PA (MVPA) obtained by the accelerometer. Results: Test-retest reliability showed ICC = 0.71 for the final score of PAQ-A. Internal consistency was α = 0.65 in the first selfreport, α = 0.67 in the retest in 82 adolescents sample, and α = 0.74 in the 232 adolescents sample. The PAQ-A was moderately correlated with total PA (rho = 0.39) and MVPA (rho= 0.34) assessed by the accelerometer. The PAQ-A obtained significantly moderate correlations in boys but not in girls against the accelerometer. Conclusions: The PAQ-A questionnaire shows an adequate reliability and a reasonable validity for assessing PA in Spanish adolescents.

Development and preliminary validation of a Family Nutrition and Physical Activity (FNPA) screening tool

Abstract: Parents directly influence children's physical activity and nutrition behaviors and also dictate the physical and social environments that are available to their children. This paper summarizes the development of an easy to use screening tool (The Family Nutrition and Physical Activity (FNPA) Screening Tool) designed to assess family environmental and behavioral factors that may predispose a child to becoming overweight. The FNPA instrument was developed using constructs identified in a comprehensive evidence analysis conducted in collaboration with the American Dietetics Association. Two or three items were created for each of the ten constructs with evidence grades of II or higher. Parents of first grade students from a large urban school district (39 schools) were recruited to complete the FNPA screening tool and provide permission to link results to BMI data obtained from trained nurses in each school. A total of 1085 surveys were completed out of the available sample of 2189 children in the district. Factor analysis was conducted to examine the factor structure of the scale. Mixed model analyses were conducted on the composite FNPA score to determine if patterns in home environments and behaviors matched some of the expected socio-economic (SES) and ethnic patterns in BMI. Correlations among FNPA constructs and other main variables were computed to examine possible associations among the various factors. Finally, logistic regression was used to evaluate the construct validity of the FNPA scale. Factor analyses revealed the presence of a single factor and this unidimensional structure was supported by the correlation analyses. The correlations among constructs were consistently positive but the total score had higher correlations with child BMI than the other individual constructs. The FNPA scores followed expected demographic patterns with low income families reporting lower (less favorable) scores than moderate or high income families. Children with a total score in the lowest tertile (high risk family environment and behaviors) had an odds ratio (OR) of 1.7 (95% CI = 1.07 – 2.80) compared to children with a total score in the highest tertile (more favorable family environment and behaviors) but this effect was reduced when parent BMI was included as a covariate. The results support the contention that the FNPA tool captures important elements of the family environment and behaviors that relate to risk for child overweight.

Associations between sedentary behavior and blood pressure in young children.

Abstract: Objective To examine the effect of sedentary behavior on blood pressure (BP) in young children using different indicators of sedentariness. Design Cross-sectional study. Setting A rural Midwestern US community. Participants Children aged 3 to 8 years (N = 111). Intervention Adiposity was assessed using dual energy x-ray absorptiometry. Objective measurements of sedentary activity were obtained from the accelerometers that participants wore continuously for 7 days. Measurements of television (TV) viewing, computer, and screen time (TV + computer) were obtained via parent report. Main Outcome Measures Systolic and diastolic BP. Results The sample spent a mean of 5 hours per day in sedentary activities, of which 1.5 hours were screen time. Accelerometer-determined sedentary activity was not significantly related to systolic BP or diastolic BP after controlling for age, sex, height, and percentage of body fat. However, TV viewing and screen time, but not computer use, were positively associated with both systolic BP and diastolic BP after adjusting for potential confounders. Participants in the lowest tertile of TV and screen time had significantly lower levels of systolic and diastolic BP than participants in the upper tertile. Conclusions Sedentary behaviors, particularly TV viewing and screen time, were associated with BP in children, independent of body composition. Other factors that occur during excessive screen time (eg, food consumption) should also be considered in the context of sedentary behavior and BP development in children.

Validation of the SenseWear Pro Armband algorithms in children.

Abstract: Introduction: The SenseWear Pro Armband (SWA) has been shown to be a valid and practical tool to assess energy expenditure (EE) in adults. However, recent studies have reported significant errors in EE estimates when the algorithms are applied to children. The purpose of this study was to assess the validity of recently developed algorithms developed to take into account children's unique movement patterns. Methods: Twenty-one healthy children (14 boys and 7girls), averaging 9.4 (1.3) yr of age, participated in a range of activities while being monitored with the SWA and a metabolic analyzer. The activity protocol lasted 41 min and included resting, coloring, playing computer games, walking on a treadmill (2, 2.5, and 3 mph), and stationary bicycling. Results: The original algorithms overestimated EE by 32%, but average error with the newly developed algorithm was only 1.7%. There were no significant differences in overall estimates of EE across the 41-min trial (P > 0.05), but there was some variability in agreement for specific activities (average absolute difference in EE estimates was 13%). The average errors in EE estimates with the new algorithms were -20.7%, -4.0%, -4.9%, -0.9%, 0.6%, 3.5%, and -25.1% for resting, coloring, computer games, walking on a treadmill (2, 2.5, and 3 mph), and biking, respectively. Biking was the only activity with significant differences in EE estimations (P < 0.001). Average minute-by-minute correlations across individuals was r = 0.71 +/- 1.3 indicating that the relationships were consistent across individuals. Conclusions: The newly developed algorithms demonstrate improved accuracy for assessing EE for typical activities in children-including accurate estimation of light activities.

Preliminary evidence of physical activity levels measured by accelerometer in Spanish adolescents: the AFINOS Study.

Abstract: Background: It is necessary to know the levels of physical activity (PA) for a better understanding of the development of chronic diseases in youth. The aim of this study was to assess levels of total PA and time spent in different PA intensities in Spanish adolescents by accelerometer. Methods: A sub-sample of 214 healthy Spanish adolescents (107 females), aged 13-16 years, enrolled in the AFINOS Study was selected for this study. Participants wore the ActiGraph GT1M accelerometer for 7 consecutive days. Total PA and time spent in sedentary, light, moderate, vigorous, and moderate to vigorous physical activity (MVPA) was estimated using the accelerometer. Adiposity was measured in the sample using sum of 6 skinfold thickness, waist circumference and BMI. Results: Adolescent boys were engaged in higher levels of total PA, moderate PA, vigorous PA and MVPA than adolescent girls, whereas girls were engaged in higher levels of light PA. Differences between age groups showed that the 15-16 years group did more total PA (P = 0.008) than the 13-14 years group. Adolescents with highest levels of body fat were less active and spent less time in vigorous PA and MVPA than adolescents with less body fat. Among the current sample, 71.1% of the adolescents (82.2% adolescent boys and 60.7% adolescent girls) reached the recommendation of  60 min in MVPA. Conclusions: Although these findings suggest that Spanish adolescents have similar PA levels than other European adolescents, further cross-sectional and longitudinal studies must assess PA levels in free-living conditions in Spanish children and adolescents using objective methods such as accelerometers, heart rate monitors and pedometers. (Nutr Hosp. 2009;24:226-232)

Prediction of BMI change in young children with the family nutrition and physical activity (FNPA) screening tool.

Abstract: Youth obesity prevention practices would be enhanced if modifiable risk factors can be identified before children become overweight. This study evaluated the predictive validity of the Family Nutrition and Physical Activity (FNPA) screening tool, a behaviorally based screening tool designed to assess family environments and behaviors that may predispose youth to becoming overweight. Parents from a large urban school district completed the FNPA screening when children were in first grade. One-year change in measured body mass index (BMI) was used as the primary outcome, and this was computed using the relative change in distance from the BMI value at the 50th percentile. Descriptive, correlation, and mixed modeling analyses were used for survey validation. Over half of the participants exhibited an increase in BMI percentile over the 1-year follow-up with an average change of 0.51 ± 11.5% which is indicative of trends to overweight. Although baseline BMI predicted BMI at follow-up, the FNPA total score explained unique variance in child BMI at follow-up after accounting for baseline BMI, parent BMI, and other demographic variables (p = 0.049). This study demonstrates the potential validity of a simple, easy-to-use screening tool for identifying children that may be at risk for becoming overweight.

Evaluation of a walking school bus for promoting physical activity in youth

Abstract: BACKGROUND: Walking to and from school has potential to increase daily physical activity among children METHODS: A Walking School Bus (WSB) intervention was implemented for 2 years in 2 schools with a third school as a control The primary aim evaluated school-wide prevalence of walking to school by self-report 6 times (fall, winter, spring) The secondary aims compared objective physical activity levels among a subsample of research participants (intervention INT = 201, control CON = 123) and between frequency of walking to school groups INT and CON participants wore an accelerometer during 4 time periods to assess daily physical activity and were measured for body mass index (BMI) and body fat each fall and spring RESULTS: School-wide prevalence of walking to school frequently (> 50% of the time each week) was 27% higher in the WSB schools than in the control school INT obtained significantly more daily physical activity than CON (780 389 vs 606 277 min/d, P Language: en

Maturity-related variation in moderate-to-vigorous physical activity among 9-14 year olds.

Abstract: Background: This study compared physical activity levels among early, average, and late maturing boys and girls. Methods: Physical activity was assessed with an Actigraph accelerometer in 161 (76 boys, 85 girls) 9 to 14 year olds over 7 consecutive days. Anthropometric variables were measured and the maturity offset (ie, years from peak height velocity) was predicted. Biological maturity groups (early, average, and late) were created based on the mean estimated age at peak height velocity for boys and girls separately. Results: Levels of moderate-to-vigorous physical activity (MVPA) were similar between early, average, and late maturing boys and girls after adjusting for differences in chronological age. Levels of MVPA progressively declined across chronological age in boys and girls (P < .001) and gender differences existed at 10-, 12-, and 13-years, with boys having higher levels than girls (P < .05). When aligned according to biological age, gender-related differences in MVPA did not exist. Conclusions...

Validation of a Computerized 24-Hour Physical Activity Recall (24PAR) Instrument With Pattern-Recognition Activity Monitors

Abstract: Purpose: The purpose of this study was to examine the validity of a computerized 24-hour physical activity recall instrument (24PAR). Methods: Participants (n = 20) wore 2 pattern-recognition activity monitors (an IDEEA and a SenseWear Pro Armband) for a 24-hour period and then completed the 24PAR the following morning. Participants completed 2 trials, 1 while maintaining a prospective diary of their activities and 1 without a diary. The trials were counterbalanced and completed within a week from each other. Estimates of energy expenditure (EE) and minutes of moderate-to-vigorous physical activity (MVPA) were compared with the criterion measures using 3-way (method by gender by trial) mixed-model ANOVA analyses. Results: For EE, pairwise correlations were high (r > .88), and there were no differences in estimates across methods. Estimates of MVPA were more variable, but correlations were still in the moderate to high range (r > .57). Average activity levels were significantly higher on the logging trial,...

Comparison of the ActiGraph acceloremeter and Bouchard diary to estimate energy expenditure in Spanish adolescents

Abstract: Introduction: The aim of this study was to evaluate the agreement between the ActiGraph accelerometer and the Bouchard diary to estimate energy expenditure (EE) in a Spanish adolescent population. Methods: Sixty-one Spanish adolescents, aged 12-16 years, were recruited for this study. The Bouchard diary and the ActiGraph were administered for 3 consecutive days. EE estimated by the Bouchard diary was calculated using 2 different MET category values (BD-Bouchard and BD-Bratteby). EE estimated by the ActiGraph was calcu- lated using 3 predictive equations (AC-Trost, AC-Freedson, and AC-Ekelund). Participants with complete 24 h data were also analyzed to control the possible loss of accuracy. Agreement was examined by Pearson and concordance cor- relations, paired t-test, and Bland-Altman method. Results: Thirty-seven adolescents were included in the analyses with complete 72 h. Relationships between EE calcu- lated by the Bouchard diary and the ActiGraph were high (ranged: r = 0.61-0.78). Concordance correlations were mod- erate (r c = 0.60) by BD-Bratteby and AC-Trost, and low using BD-Bratteby and AC-Ekelund (r c = 0.15). EE estimated by BD-Bratteby and AC-Trost also showed no significant differ- ences (P > 0.05) and absolutely agree 0.0 ± 5.0 MJ/d (95% con- fidence interval: ± 0.90 MJ/d), but with wide limits of agree- ment (± 9.80 MJ/d). Relationships were higher and differences were smaller in the 72 h sample than in the 24 h sample. Conclusions: The Bouchard diary and the ActiGraph showed high relationships, moderate concordance, and large differences to estimate EE in Spanish adolescents. Advantages, disadvantages, and agreements between both instruments must be taking into consideration for health- related research. (Nutr Hosp. 2009;24:701-710) DOI:10.3305/nh.2009.24.6.4555

Assessing the Built Environment using GPS, Physical Activity Monitors and Geospatial Surveys

Abstract: Understanding what aspects of the built environment contribute to health concerns such as obesity is not an easy task, due to the scale of the built environment and inconsistencies in community design, climate and culture. It is therefore necessary to look at the detailed layers of the built environment to better understand what components may have the largest impact. This can be a daunting task. Through the use of participatory research methods, geospatial tools and physical activity recording devices, it is possible to create models of how people interact with their environment. This paper discusses how geospatial technologies along with physical activity monitors have been used to determine if the urban forest, a component of the built environment, influences an individual’s decision to use a particular walking/running route in Ames, Iowa, USA.