Pediatric Weight Management

Pediatrics and Physical Activity


Storey ML, Forshee RA, Weaver AR, Sansalone WR. Demographic and lifestyle factors associated with body mass index among children and adolescents. Int J Food Sci Nutr 2003; 54: 491-503.

PubMed ID: 14522695
Study Design:
Non-Randomized Cross-Sectional Study
D - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:
To examine the relationship and relative strength of associations of demographic and lifestyle factors in predicting BMI among children and adolescents using multivariate regression models. Key variables in the analyses included race, age, gender, sedentary behavior, and dietary components, including intake of added sugars
Inclusion Criteria:
  • Non-Institutionalized Americans over the age of 2
  • Participant of either the Continuing Survey of Food Intake for Individuas (CSFII) and National Health and Nutrition Examination Survey III (NHANES).
Exclusion Criteria:
  • Not applicable
Description of Study Protocol:

Recruitment: Participant of the National sampling for Continuing Survey of Food Intake for Individuas (CSFII) and National Health and Nutrition Examination Survey III (NHANES).

Design: Non-Randomized Cross-Sectional Study    

Statistical Analysis: Multivariate regression models (to examine the association between demographic and lifestyle variables and the body mass index of children and adolescents).

Data Collection Summary:

Timing of Measurements:

Data from the CSFII and the NHANES included 2 24-hour multi-pass dietary recall instructions administered on two non-consecuitive days. CSFII uses self-reported wt & ht; NHANES uses measured ht & wt.

Dependent Variables

  • BMI (measured ht & wt from NHANES data; self-reported from CSFII data)

Independent Variables

  • Age
  • Race
  • Gender
  • Family income (% poverty line)
  • Hours of television watching (self-reported)
  • Participation in team sports/Organized physical activity (self-reported)
  • Total physical activity (self-reported)
  • Dietary variables grams of protein, fat, alcohol, carbohydrates
  • Less added sugars & added sugars (distinguishes between sugars added to foods during processing & those that occur naturally in foods).

Control Variables: 

  • Total energy
  • Older & Younger Age groups
Description of Actual Data Sample:
N=Initial:  CSFII sample contained a total of 5739 children & 4182 adolescents; NHANES survey was a sample of 4720 children and 2216 adolescents.


  • CSFII sample: 4806 children & 3966 adolescents (88.4% of original sample)
  • NHANES sample: 1808 children & 1665 adolescents (50.1% of original sample).

Attrition: Cases with missing or invalid data for some variable.

Age: Children aged 6-11 y & adolescents aged 12-19 y (CSFII) and aged 12-16 y (NHANES).

Ethnicity: Nationally representative sample.

Location: Nationally representative sample.

Summary of Results:


  • Diet had a weak association with BMI. None of the diet variables for children was statistically significant in either the NHANES or the CSFII model.
  • Dietary fat was not significantly with BMI in CSFII adolescents.
  • There was a statistically significant, negative association between grams of total fat and BMI in the NHANES-adolescent model. A 1-g increase in total fat decreased predicted BMI by 0.007 (P<0.01).
  • Carbohydrates (less added sugars) had a statistically significant inverse relationship to BMI among CSFII adolescents (subjects age 12-19) p<0.01.
  • Added sugars were not associated with BMI among children and adolescents in either of the 2 surveys.


Sedentary behavior & Physical activity:

Television Viewing:

  • In both children and adolescents, television viewing was markedly associated with BMI. Sedentary behavior (as measured by television viewing) and physical activity had relatively strong associates with BMI for both children & adolescents. Controlling for the other variables in the model, the predicted BMI of the CSFII children and the CSFII adolescents increased by 0.172 (p<0.001) and 0.205 (p<0.001), respectively for each additional hour of television viewing.
  • In the NHANES, the predicted BMI of NHANES children increased by 0.25 (P<0.001) for each additional hour of television viewing. The coefficient for television viewing among the NHANES adolescents was positive (0.17), but was not statistically significant.

 Participation in team sports/organized physical activity:

  • Participation in team sports/organized physical activity was associated with a lower BMI (negatively associated with BMI). A NHANES child’s predicted BMI was reduced by 0.29 (P<0.01) for each team/organized physical activity in which he/she participated. Among the NHANES adolescents, the predicted BMI was reduced by 0.47 (P<0.01) for each team/organized physical activity.
  • The exercise variable from this dataset (how many times a week you exercised harder enough to break a sweat) had a counter-intuitive relationship with BMI for the NHANES children. For each additional exercise event per week, a child’s BMI was predicted to increase by 0.13 (P<0.01). The association for adolescents was also positive, but was not statistically significant.
Author Conclusion:
While diet had little or no predictive value for BMI, television viewing habits and physical activity do matter. Children and adolescents who report spending more hours watching television, videos, or using a computer have higher BMI scores.
Funding Source:
Sugar Association Inc
Commodity Group:
University/Hospital: Virginia Polytechnic Institute and State University, Georgetown University Center for Food and Nutrition Policy
Reviewer Comments:
  • CSFII uses average of 2 24-h recalls; NHANES uses measured ht & wt.
  • CSFII uses self-reported ht & wt.
  • Nationally-representative samples.
  • Mean BMI in CSFII sample was slightly higher than that from the NHANES sample.
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) N/A
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? Yes
  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? Yes
3. Were study groups comparable? N/A
  3.1. Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT) N/A
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? N/A
  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? N/A
  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.) N/A
  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%.) Yes
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? N/A
  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? Yes
  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.) Yes
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? Yes
  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? Yes
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? Yes
  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? Yes
  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? No
  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? Yes
  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? N/A
  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)? Yes
  8.6. Was clinical significance as well as statistical significance reported? Yes
  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? Yes
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.2. Was the study free from apparent conflict of interest? Yes