Kathleen B. Watson

Pedometer reliability, validity and daily activity targets among 10- to 15-year-old boys

Abstract The aims of this study were to: (1) determine whether the number of pedometer counts recorded by adolescents differs according to the adiposity of the participant or location on the body; (2) assess the accuracy and reliability of pedometers during field activity; and (3) set adolescent pedometer-based physical activity targets. Seventy-eight 11- to 15-year-old Boy Scouts completed three types of activity: walking, fast walking and running. Each type was performed twice. Participants wore three pedometers and one activity monitor during all activities. Participants were divided into groups of normal weight (BMI < 85th percentile) and at risk of being overweight (BMI ⩾ 85th percentile). Intra-class correlations across the three activities indicated reliability (r = 0.51 – 0.92, P < 0.001). This conclusion was supported by narrow limits of agreement that were within a pre-set range that was practically meaningful. Multivariate analysis of covariance indicated adiposity group differences, but this difference was a function of the increased stature among the larger participants (P < 0.001). Ordinary least-squares regression models and multi-level regression models showed positive associations between the number of pedometer and activity monitor counts recorded by the three groups of participants during all activities (all P < 0.001). The mean number of counts recorded for all participants during the fast walk was 127 counts per minute. In conclusion, the pedometers provided an accurate assessment of adolescent physical activity, and a conservative estimate of 8000 pedometer counts in 60 min is equivalent to 60 min of moderate to vigorous physical activity.

Comparison of a Web-Based versus Traditional Diet Recall among Children

Self-administered instruments offer a low-cost diet assessment method for use in adult and pediatric populations. This study tested whether 8- to 13-year-old children could complete an early version of the Automated Self Administered 24-hour diet recall (ASA24) and how this compared to an interviewer-administered 24-hour diet recall. One-hundred twenty 8- to 13-year-old children were recruited in Houston from June through August 2009 and randomly assigned to complete either the ASA24 or an interviewer-administered 24-hour diet recall, followed by the other recall mode covering the same time interval. Multivariate analysis of variance, testing for differences by age, sex, and ethnic/racial group, were applied to percentages of food matches, intrusions, and omissions between reports on the ASA24 and the interviewer-administered 24-hour diet recall. For the ASA24, qualitative findings were reported regarding ease of use. Overall matches between interviewer-administered and ASA24 self-administered 24-hour diet recall was 47.8%. Matches were significantly lower among younger (8- to 9-year-old) compared with older (10- to 13-year-old) children. Omissions on ASA24 (18.9% overall) were most common among 8-year-olds and intermediate among 9-year-olds. Eight- and 9-year-olds had substantial difficulties and often required aid in completing ASA24. Findings from this study suggest that a simpler version of an Internet-based diet recall program would be easier for children to use.

The Impact of the Texas Public School Nutrition Policy on Student Food Selection and Sales in Texas

OBJECTIVES We assessed the statewide impact of the 2004 Texas Public School Nutrition Policy on foods and beverages served or sold in schools. METHODS We collected lunch food production records from 47 schools in 11 Texas school districts for the school years before (2003-2004) and after (2004-2005) policy implementation. Cafeteria servings of fruit, vegetables (regular and fried), and milk served each day were calculated. Twenty-three schools from 5 districts provided records of à la carte sales of candy, chips, desserts, drinks, ice cream, and water. We examined aggregated school-level differences in total items served or sold per day per student between study years. RESULTS School demographics were similar to state data. Regardless of district and school size, cafeterias served significantly fewer high-fat vegetable items per student postpolicy (P < .001). Postpolicy snack bar sales of large bags of chips were significantly reduced (P = .006), and baked chips sales significantly increased (P = .048). CONCLUSIONS School food policy changes have improved foods served or sold to students. It is not known whether improved lunch choices influence consumption for the whole day.

Children’s accuracy of portion size estimation using digital food images: effects of interface design and size of image on computer screen

OBJECTIVE To test the effect of image size and presence of size cues on the accuracy of portion size estimation by children. DESIGN Children were randomly assigned to seeing images with or without food size cues (utensils and checked tablecloth) and were presented with sixteen food models (foods commonly eaten by children) in varying portion sizes, one at a time. They estimated each food models portion size by selecting a digital food image. The same food images were presented in two ways: (i) as small, graduated portion size images all on one screen or (ii) by scrolling across large, graduated portion size images, one per sequential screen. SETTING Laboratory-based with computer and food models. SUBJECTS Volunteer multi-ethnic sample of 120 children, equally distributed by gender and ages (8 to 13 years) in 2008-2009. RESULTS Average percentage of correctly classified foods was 60·3 %. There were no differences in accuracy by any design factor or demographic characteristic. Multiple small pictures on the screen at once took half the time to estimate portion size compared with scrolling through large pictures. Larger pictures had more overestimation of size. CONCLUSIONS Multiple images of successively larger portion sizes of a food on one computer screen facilitated quicker portion size responses with no decrease in accuracy. This is the method of choice for portion size estimation on a computer.

Development of the Comprehensive General Parenting Questionnaire for caregivers of 5-13 year olds

BackgroundDespite the large number of parenting questionnaires, considerable disagreement exists about how to best assess parenting. Most of the instruments only assess limited aspects of parenting. To overcome this shortcoming, the “Comprehensive General Parenting Questionnaire” (CGPQ) was systematically developed. Such a measure is frequently requested in the area of childhood overweight.MethodsFirst, an item bank of existing parenting measures was created assessing five key parenting constructs that have been identified across multiple theoretical approaches to parenting (Nurturance, Overprotection, Coercive control, Behavioral control, and Structure). Caregivers of 5- to 13-year-olds were asked to complete the online survey in the Netherlands (N = 821), Belgium (N = 435) and the United States (N = 241). In addition, a questionnaire regarding personality characteristics (“Big Five”) of the caregiver was administered and parents were asked to report about their child’s height and weight. Factor analyses and Item-Response Modeling (IRM) techniques were used to assess the underlying parenting constructs and for item reduction. Correlation analyses were performed to assess the relations between general parenting and personality of the caregivers, adjusting for socio-economic status (SES) indicators, to establish criterion validity. Multivariate linear regressions were performed to examine the associations of SES indicators and parenting with child BMI z-scores. Additionally, we assessed whether scores on the parenting constructs and child BMI z-scores differed depending on SES indicators.ResultsThe reduced questionnaire (62 items) revealed acceptable fit of our parenting model and acceptable IRM item fit statistics. Caregiver personality was related as hypothesized with the GCPQ parenting constructs. While correcting for SES, overprotection was positively related to child BMI. The negative relationship between structure and BMI was borderline significant. Parents with a high level of education were less likely to use overly forms of controlling parenting (i.e., coercive control and overprotection) and more likely to have children with lower BMI. Based on several author review meetings and cognitive interviews the questionnaire was further modified to an 85-item questionnaire.ConclusionsThe GCPQ may facilitate research exploring how parenting influences children’s weight-related behaviors. The contextual influence of general parenting is likely to be more profound than its direct relationship with weight status.

6-n-propylthiouracil taster status not related to reported cruciferous vegetable intake among ethnically diverse children.

Sensitivity to the taste of 6-n-propylthiouracil (PROP) (a bitter chemical related to the phenylthiocarbamide found in cruciferous vegetables) has been related to dietary intake or preferences of cruciferous vegetables among adults and young children but not middle-aged children or adolescents. We hypothesized that PROP taste sensitivity is related to lower reported dietary intake of cruciferous vegetables, primarily among younger children (ie, a moderating effect of child age). This study examined the relationship of PROP sensitivity to reported dietary intake across 3 days in 2 age groups of youth (9-10 and 17-18 years) while statistically controlling for physical activity, social desirability, and reporting bias. Cross-sectional design was used with a multiethnic (white, African American, Hispanic, etc) sample of 843 men and women. Children were recruited from and data were collected in local elementary and high schools that had at least 30% ethnic minority enrollment. Children providing nonplausible reports of dietary intake were deleted from the analyses. Body mass index was calculated and expressed in z scores. Energy intake and physical activity were measured by 3 telephone-conducted 24-hour dietary recalls with the Nutrient Data System for Research and 5 days of Actigraph (ActiGraph, Shalimar, Florida) activity monitor. The primary analyses included 347 students. 6-n-Propylthiouracil sensitivity was not related to intake of cruciferous vegetables. Intakes of the cruciferous vegetables were low, which may explain the lack of relationship.

Differences in fruit and vegetable exposure and preferences among adolescents receiving free fruit and vegetable snacks at school.

Low fruit and vegetable (FV) intakes are associated with excess body weight. The United States Department of Agriculture sponsors a Free Fruit and Vegetable Program in schools whereby students receive free FV snacks daily. This study assessed whether the program improved student exposure to and preferences for FV in a Houston high school in 2006-2007. Anonymous, post-intervention only FV exposure and preference surveys were completed by 2000 intervention school students and 1600 students in a comparison school during May, 2007. Differences in FV exposure and preferences were assessed, as well as differences in preferences between those students who tasted the item for the first time at school compared to those who had tasted the item before. The comparison school average scores for prior FV exposure and vegetable preferences were significantly higher than the intervention school scores. Intervention school students who had tasted the item previously reported significantly higher preferences than students who had tasted it for the first time at school. Access to the Free Fruit and Vegetable Program did not appear to improve high school student reported FV exposure and preferences. Future research should investigate the connection between food exposure, preferences and consumption in adolescents.

Field evaluation of energy expenditure from continuous and intermittent walking in women.

RATIONALE Recent physical activity recommendations suggest that comparable amounts of prescribed physical activity, done as a single continuous bout or as a set of intermittent bouts, will produce equal amounts of energy expenditure (EE) during the prescribed activity as well as throughout the day. HYPOTHESES In a field setting, we tested two hypotheses: (1) continuous and intermittent walking conditions will result in significantly greater total daily EE than a control condition, and (2) continuous and intermittent walking conditions will result in similar total daily METHODS Thirty women (mean age [yr] = 43.7+/-5.8; mean body mass index [kg x m(-2)]= 24.7+/-4.0) participated in a repeated-measures design so that each woman participated in three walking conditions on successive days of the week: a single 30-min brisk walk (continuous): three 10-min brisk walks (intermittent); and no activity (control). Throughout the study protocol, women wore a TRITRAC-R3D accelerometer programmed to estimate EE in 2-min intervals. RESULTS Mean total EE estimates (kcal) for the three walking conditions were as follows: continuous: 2181+/-308; intermittent: 2121+/-305; and control: 1948+/-270. A repeated-measures analysis of variance omnibus test indicated that EE differed significantly by experimental condition [F(2,58) = 40.2, P < 0.001). To test the first hypothesis, contrasts were examined revealing that EE in the continuous and intermittent conditions was significantly greater than EE in the control condition [F(1,29) = 58.2, P < 0.001]. To test the second hypothesis, contrasts revealed that EE in the continuous condition was significantly greater than EE in the intermittent condition [F(1,29) = 7.0, P = 0.013]. CONCLUSION For the purposes of total EE, selecting a continuous mode of walking may offer additional benefit over an intermittent mode, given the same total prescribed duration.

Self efficacy for fruit, vegetable and water intakes: Expanded and abbreviated scales from item response modeling analyses.

ObjectiveTo improve an existing measure of fruit and vegetable intake self efficacy by including items that varied on levels of difficulty, and testing a corresponding measure of water intake self efficacy.DesignCross sectional assessment. Items were modified to have easy, moderate and difficult levels of self efficacy. Classical test theory and item response modeling were applied.SettingOne middle school at each of seven participating sites (Houston TX, Irvine CA, Philadelphia PA, Pittsburg PA, Portland OR, rural NC, and San Antonio TX).Subjects714 6th grade students.ResultsAdding items to reflect level (low, medium, high) of self efficacy for fruit and vegetable intake achieved scale reliability and validity comparable to existing scales, but the distribution of items across the latent variable did not improve. Selecting items from among clusters of items at similar levels of difficulty along the latent variable resulted in an abbreviated scale with psychometric characteristics comparable to the full scale, except for reliability.ConclusionsThe abbreviated scale can reduce participant burden. Additional research is necessary to generate items that better distribute across the latent variable. Additional items may need to tap confidence in overcoming more diverse barriers to dietary intake.

The Impact of School Socioeconomic Status on Student Lunch Consumption after Implementation of the Texas Public School Nutrition Policy

BACKGROUND This study compares the impact of the Texas Public School Nutrition Policy on lunch consumption of low- and middle-income students in sixth through eighth grades. METHODS Students in 1 middle socioeconomic status (SES) and 1 low SES school completed lunch food records before (2001/2002) and after (2005/2006) implementation of the Texas policy. Students recorded amount and source of foods/beverages consumed. Two-way analyses of variance with year and school SES as factors were performed to compare consumption by school SES before and after implementation of the Texas policy. RESULTS Regardless of year, the low SES group consumed less fat, sweetened beverages, and candy and more vitamin C and calcium than the middle SES group. There were more significant improvements in dietary patterns for the middle SES school students post-policy, particularly from the National School Lunch Program (NSLP) meal. The middle SES school students reported significantly higher percentages of less healthy items from home post-policy. CONCLUSIONS Overall, low SES school students consumed more healthy lunches at school compared with middle SES school students, and the Texas policy improved middle SES school student dietary intakes. Whether the dietary behaviors in school influence dietary intake for the entire day is unknown.