Pediatric Weight Management

Pediatrics and Physical Activity

Citation:

Salbe, AD., Weyer, C., Harper, I., Lindsay, RS., Ravussin, E., & Tataranni, A. Assessing risk factors for obesity between childhood and adolescence:  II.  Energy metabolism and physical activity.  Pediatrics 2002;110:307-314.

PubMed ID: 12165583
 
Study Design:
Longitudinal
Class:
C - Click here for explanation of classification scheme.
Quality Rating:
Positive POSITIVE: See Quality Criteria Checklist below.
Research Purpose:

The aims of the study were:

  1. to assess total energy expenditure, resting metabolic rate, physical activity level, and the RQ at 5 and 10 years of age;
  2. to examine metabolic predictors of obesity between childhood and the onset of adolescence; and
  3. to determine whether these predictive characteristics track in a longitudinal manner.
Inclusion Criteria:

Children were healthy and of full Indian and at least 75% Pima-Papago heritage.

Exclusion Criteria:
Children were excluded if their mothers were known to have had diabetes before or during the pregnancy of interest.
Description of Study Protocol:

Anthropometric measurements (height and weight) were collected on all children at 5 and 10 years old. Doubly labeled water was given to all 5 year olds and 53 10 year olds (because of a worldwide shortage).  Body water, calculated from O dilution spaces, was used to assess body composition in the 5 year old and 53 of the 10 year olds.  DEXA was used on the remaining 85 10 year olds to assess body composition.  RMR and TEE were measured and AEE and PAL were calculated.  A physical activity questionnaire was completed by the parent.

Statistical Analysis

Linear regression models were used to assess the effects of the baseline variables on the development of obesity.

Data Collection Summary:

Dependent Variables

  • percentage of body fat and body weight at age 5 years
  • percentage of body fat and body weight at age 10 years, AEE, PAL

Independent Variables

  • number of hours of sport activity per week

Control Variables

Description of Actual Data Sample:

Initial N: 176 Pima Indian.

Attrition (final N): Sample size was reduced to 138 (65 boys and 73 girls) because of exclusion criteria.

Age: 5 year olds were studied and followed up again 5 years later

Ethnicity: Pima Indian

Other relevant demographics:

Anthropometrics height and weight at 5 and 10 years old

Location:

Summary of Results:

Cross sectionally, percentage of body fat and body weight at 5 and 10 years of age were negatively correlated with sports participation (r=-0.23,P=0.01; r=-0.26,P=0.004)

Author Conclusion:

This study confirms previous prospective investigations that have shown that low rates of energy expenditure and fat oxidation in early childhood do not predict the development of obesity in children 5 years later. However, the results do indicate that differential changes in physical activity take place in children who are at different risks of developing obesity and that failure to increase physical activity in response to weight gain may promote obesity in preadolescence.

Funding Source:
Reviewer Comments:

At age 5 years, obesity is associated with decreased participation in sports

At age 10 years, obesity is associated with decreased participation in sports

Limitations:

Possible measurement error in the activity questionnaires. Some inconsistencies between some of the activity variables and adiposity and body weight.

Strengths:

Longitudinal

 

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? 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? Yes
  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? Yes
  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? Yes
  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? 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? No
  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? No
  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? 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? Yes
  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? 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)? Yes
  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? Yes
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.2. Was the study free from apparent conflict of interest? Yes