Pediatric Weight Management

Pediatrics and Physical Activity


Gray A., & Smith, C. (2003). Fitness, dietary intake, and body mass index in urban native American youth. Journal of American Dietetic Association, 103(9), 1187-1191.

PubMed ID: 12963950
Study Design:
Cross-Sectional Study
D - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:

To investigate correlations among physical fitness, activity levels, dietary intake, and BMI for an urban native American youth population.

Inclusion Criteria:
Exclusion Criteria:
Description of Study Protocol:

Participants reported the frequency of 21 activities which were then categorized into 3 energy expenditure levels (vig, mod, sed). Surveys were self administered for older youth and researcher administered for younger youth

Statistical Analysis

Normally distributed data was analyzed using 1-way ANOVA and pearson correlations while non-normally distributed data was analyzed with the Mann-Whitney or Kurskal-Wallis test and Spearman Correlation.

Data Collection Summary:

Dependent Variables

  • Fitness: Presidential Fitness
  • Flexibility – v-sit
  • Endurance - ¼, ½, 1 mile run
  • Agility - Shuttle run
  • Ab strength – partial curl-ups
  • Upper body strength – push-ups 
  • Balance – one leg stand
  • BMI – ht, wt.
  • Skin folds – 4 site
  • Mid-arm circumference

Independent Variables

  • Age

Control Variables

  • None
Description of Actual Data Sample:

Initial N: 155 urban native American youth age 5-18.

Attrition (final N):

Age: age 5-18

Ethnicity: native American

Other relevant demographics: urban, youth

Anthropometrics (e.g., were groups same or different on important measures)


Summary of Results:


Energy and macronutrient intakes were not correlated to BMI.

Youth may have underreported energy intake because they did not understand portion sizes, could not remember what they ate, or because they were embarrassed to report actual intake.

Soda pop consumption (soda pop not defined) was correlated to higher energy consumption and increased with age, but not with increased BMI (p values not provided).

Physical Activity

Significant correlations were found between BMI and activity level (-.26) and fitness (-.25) for older adolescents p< .05.

TV Watching

Increased tv viewing was associated with an increase in BMI for children age 9-18

Author Conclusion:
  • Activity levels were only associated with a lower BMI in youth age 9-18. Younger children may have difficulty reporting activity levels and “fidgeting” may expend energy but be lost as a recorded activity.
  • Based on the results of this study, the authors suggest that efforts be made to incorporate an exercise component in nutrition education programs designed for youth.
  • Because many urban neighborhoods are unsafe, especially after dark, efforts should be made to incorporate more activities in the school setting.
Funding Source:
Reviewer Comments:

Strengths: Study conducted among urban Native American population.

Limitations: Incomplete results for dietary intake – no statistics reported.

Quality Criteria Checklist: Primary Research
Relevance Questions
  1. Would implementing the studied intervention or procedure (if found successful) result in improved outcomes for the patients/clients/population group? (Not Applicable for some epidemiological studies) N/A
  2. Did the authors study an outcome (dependent variable) or topic that the patients/clients/population group would care about? Yes
  3. Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? Yes
  4. Is the intervention or procedure feasible? (NA for some epidemiological studies) Yes
Validity Questions
1. Was the research question clearly stated? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? Yes
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.3. Were the target population and setting specified? Yes
2. Was the selection of study subjects/patients free from bias? Yes
  2.1. Were inclusion/exclusion criteria specified (e.g., risk, point in disease progression, diagnostic or prognosis criteria), and with sufficient detail and without omitting criteria critical to the study? N/A
  2.2. Were criteria applied equally to all study groups? Yes
  2.3. Were health, demographics, and other characteristics of subjects described? Yes
  2.4. Were the subjects/patients a representative sample of the relevant population? No
3. Were study groups comparable? No
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) No
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? No
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) N/A
  3.4. If cohort study or cross-sectional study, were groups comparable on important confounding factors and/or were preexisting differences accounted for by using appropriate adjustments in statistical analysis? ???
  3.5. If case control study, were potential confounding factors comparable for cases and controls? (If case series or trial with subjects serving as own control, this criterion is not applicable.) ???
  3.6. If diagnostic test, was there an independent blind comparison with an appropriate reference standard (e.g., "gold standard")? N/A
4. Was method of handling withdrawals described? Yes
  4.1. Were follow-up methods described and the same for all groups? N/A
  4.2. Was the number, characteristics of withdrawals (i.e., dropouts, lost to follow up, attrition rate) and/or response rate (cross-sectional studies) described for each group? (Follow up goal for a strong study is 80%.) No
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? Yes
  4.5. If diagnostic test, was decision to perform reference test not dependent on results of test under study? N/A
5. Was blinding used to prevent introduction of bias? N/A
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? N/A
  5.2. Were data collectors blinded for outcomes assessment? (If outcome is measured using an objective test, such as a lab value, this criterion is assumed to be met.) N/A
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? N/A
  5.4. In case control study, was case definition explicit and case ascertainment not influenced by exposure status? N/A
  5.5. In diagnostic study, were test results blinded to patient history and other test results? N/A
6. Were intervention/therapeutic regimens/exposure factor or procedure and any comparison(s) described in detail? Were interveningfactors described? Yes
  6.1. In RCT or other intervention trial, were protocols described for all regimens studied? N/A
  6.2. In observational study, were interventions, study settings, and clinicians/provider described? Yes
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? N/A
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? N/A
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? N/A
  6.6. Were extra or unplanned treatments described? N/A
  6.7. Was the information for 6.4, 6.5, and 6.6 assessed the same way for all groups? N/A
  6.8. In diagnostic study, were details of test administration and replication sufficient? N/A
7. Were outcomes clearly defined and the measurements valid and reliable? Yes
  7.1. Were primary and secondary endpoints described and relevant to the question? Yes
  7.2. Were nutrition measures appropriate to question and outcomes of concern? Yes
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? N/A
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? Yes
  7.5. Was the measurement of effect at an appropriate level of precision? No
  7.6. Were other factors accounted for (measured) that could affect outcomes? Yes
  7.7. Were the measurements conducted consistently across groups? Yes
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? Yes
  8.1. Were statistical analyses adequately described and the results reported appropriately? Yes
  8.2. Were correct statistical tests used and assumptions of test not violated? Yes
  8.3. Were statistics reported with levels of significance and/or confidence intervals? Yes
  8.4. Was "intent to treat" analysis of outcomes done (and as appropriate, was there an analysis of outcomes for those maximally exposed or a dose-response analysis)? N/A
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? N/A
  8.6. Was clinical significance as well as statistical significance reported? No
  8.7. If negative findings, was a power calculation reported to address type 2 error? N/A
9. Are conclusions supported by results with biases and limitations taken into consideration? Yes
  9.1. Is there a discussion of findings? Yes
  9.2. Are biases and study limitations identified and discussed? Yes
10. Is bias due to study's funding or sponsorship unlikely? N/A
  10.1. Were sources of funding and investigators' affiliations described? N/A
  10.2. Was the study free from apparent conflict of interest? N/A