Pediatric Weight Management

PWM: Physical Activity and Inactivity of Youth (2006)


Guillaume M, Lapidus L, Bjorntorp P, Lambert A. Physical activity, obesity and cardiovascular risk factors in children. The Belgian Luxembourg child study II. Obesity Research 1997; 5: 549-556.

PubMed ID: 9449139
Study Design:
Cross-Sectional Study
D - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:

The purpose of this study was to describe the physical activity and inactivity of Belgian children.

Inclusion Criteria:

Only children of Belgian nationality with at least on parent of Belgian origin were included.

Exclusion Criteria:
Not specified.
Description of Study Protocol:

The examination included responding to standardized questionnaires on psychosocial and economic variables as well as a 3-day nutritional log.


Measurements of height, weight, waist and hip circumference and triceps and subscapular skin folds were taken. BMI and hip to waist ratios were calculated.  All procedures were conducted in a fasting condition.

TV viewing was reported by both parents and children.

Statistical Analyses:

Chi-square ANOVA of categorical data using likelihood ratio tests was performed to analyze the association between categorical data and homogeneity of the frequencies.

A univariate multiple regression model was fitted with CV risk factors or anthropometric variables as response variables.  Age sport activity and the number of days per week watching TV were considered to be predictor variables.

Data Collection Summary:

Dependent Variables

  • BMI
  • Bodyweight
  • Skin fold (triceps)
  • Hip to waist ratio

Independent Variables

  • Age group (6-8, 8-10, 10-12)
  • Gender
  • Number of days/week watching TV -  # of hours of TV watched per day (<3, 3-5, 6-7, and no response)
  • Duration of sport activities –hours per week (<.5, .5 to <1.5, 1.5 to <2.5, >2.5, and no response)


  • Nationality (Belgian)
  • Age (sample groups)
  • Gender
Description of Actual Data Sample:

1028 children from school classes in Province de Luxembourg. Participation rate was about 70% of those selected and there were no anthropometric differences between those that participated and those that did not.

Summary of Results:

TV watching showed a relationship with CV risk factors, adjusted for age. Body weight was significantly related to days per week or TV in both boys (p = .012) and girls (p = .027).  In boys a significant relation was observed with BMI (p = .039) and marginally with triceps skin fold (p = .065) but when TV watching was considered independent of the influence of age and sports activities, a significant relationship was remaining for BMI for boys (p = .04).

For boys, sport activity showed an independent relationship to subscapular skin fold (p = .04) and borderline effect for triceps skin fold ( p = .09).

Days of TV watching recorded by parents and child were significantly correlated.

Hours of TV watching were significantly larger from child report than from parent report.

Author Conclusion:

Bodyweight was significantly correlated with number of days watching TV in boys but not girls. BMI showed similar associations.


Taken together, both TV watching (positively) and sports activity (negatively) showed independent determination of body fat mass in boys but not girls.

Overall conclusion:

TV watching (positively) and sports activities (negatively) are associated with bodyweight and, in boys, with measurements of body fat.

Funding Source:
University/Hospital: National Center for Research in Nutrition and Health (Belgium), University of Goteborg Sahlgren's Hospital (Sweden), Catholic University of Louvain (Belgium)
Reviewer Comments:


  • 84-93% of sample reported watching TV 6-7 days a week.
  • The frequency of TV viewing was used as the predominant IV because similar reports fro parents and child but this variable is not very discriminative.
  • Effect was possibly confounded by SES.  Boys of higher SES reported more activity while girls of higher SES watched more TV.
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? N/A
  3. Is the focus of the intervention or procedure (independent variable) or topic of study a common issue of concern to dieteticspractice? N/A
  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? N/A
  2.3. Were health, demographics, and other characteristics of subjects described? N/A
  2.4. Were the subjects/patients a representative sample of the relevant population? N/A
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? 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? No
  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? N/A
  6.3. Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect? No
  6.4. Was the amount of exposure and, if relevant, subject/patient compliance measured? No
  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? Yes
  7.6. Were other factors accounted for (measured) that could affect outcomes? Yes
  7.7. Were the measurements conducted consistently across groups? N/A
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? N/A
  8.2. Were correct statistical tests used and assumptions of test not violated? N/A
  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)? N/A
  8.6. Was clinical significance as well as statistical significance reported? N/A
  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? N/A
  9.2. Are biases and study limitations identified and discussed? N/A
10. Is bias due to study's funding or sponsorship unlikely? Yes
  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