Pediatrics and Physical Activity

Study Design:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:

The purpose of this case-control study was to identify predictors of obesity among Puerto Rican children from Hartford, CT.

Specifically, among Puerto Rican children living in the mainland U.S.:

  1. Do the diets of obese children diets differ from those of nonobese children in terms of energy, macronutrients and food group intake?
  2. Do obese children have different TV viewing and activity and inactivity patterns from those of nonobese children?
  3. Is maternal obesity associated with the child’s obesity?
  4. Do obese children have different birthweights and infant feeding profiles compared with their nonobese counterparts?
  5. Does socioeconomic status influence the likelihood of childhood obesity?
  6. Is obesity associated with negative health consequences during childhood?
Inclusion Criteria:

To be included in the study, children had to meet the following criteria:

  1. Be of Puerto Rican ethnicity
  2. Be between the ages of seven and 11 years
  3. Be free from diagnosed endocrine conditions that could lead to obesity.
Exclusion Criteria:
  • Wasted
  • Menarche
  • Endocrine problems.
Description of Study Protocol:


Children caretakers were recruited from:

  • The participants list of a previous nutrition knowledge survey (N=17)
  • Street outreach through a recruitment flier (N=12)
  • One school clinic (N=17)
  • Referrals by HHC employees (N=7).

Group Membership

  • Children were classified as obese [N=29, body mass index (BMI)>85th percentile] or controls (N=24, BMI<85th percentile).

Statistical analyses

  • Bivariate analysis between groups
  • Multivariate analysis modeling for those variables with p<0.20 in bivariate analysis
  • Final model: Maternal BMI, TV, fruit juice intake, dairy intake, marital status.
Data Collection Summary:

Data Gathered, Dietary Intake

Gathered via Food Frequency Questionnaire administered to the caretaker directly with the active participation of the child,

Data gathered in stages:

  1. First stage: A complete list of all foods and beverages consumed during the preceding day was obtained.
  2. Second stage: Detailed description of all of the beverages consumed, including cooking methods and brand names were recorded, together with the time and place of consumption.
  3. Third stage: Estimates of the amounts of all foods and beverages consumed were obtained. Paper models were used (National Dairy Council, Teacher’s guide) to assist respondents with the portion size estimations.
  4. Fourth stage: The food recall was reviewed to ensure that all items had been recorded correctly.

Physical Activity

  • Children’s physical activity and inactivity were assessed through a 13-item physical activity questionnaire developed from the Harvard Medical School’s survey "Growing Up in the 90’s."


  • Weight, height, triceps skinfold and waist and hip circumferences were measured in children and their mothers by a single researcher following standard procedures. Measurements were recorded twice, and the average of the two measurements was used in the analysis.

Food Insecurity

  • The 10-item Radimer/Cornell hunger scale was used to assess food insecurity patterns.


Overweight (measured BMI=85th percentile)
[Note: Called “obesity” in paper.]

Independent: Food insecurity in past month (10-item Radimer/Cornell hunger scale)

  • None = Food secure
  • Mild = Household level
  • Moderate = Caregiver level
  • Severe = Child level.

Control Variables: No multivariate analysis for food insecurity (did not make it into final model).

Description of Actual Data Sample:

N: 53 male and female

  • 19 obese, 12 control girls
  • 10 obese, 12 control boys

Age: 7-11 y


Ethnicity: Puerto Rican

Location: Hartford, CT.

Summary of Results:

Food Insecurity

Question or factor Obese (%) Control (non-obese) (%) Significance
Caretakers answered positively to “I can’t afford to eat properly” 10.7 39.1 p=0.02
Caretakers food insecure 0 36.4 p=0.01
Household food secure 28.6 17.4 p=0.35
Household food insecure 46.4 39.1 p=0.60
Caretaker insecure 25.0 34.8 p=0.45
Child hunger 0 8.7 p=0.11

Prevalences of food insecurity in overweight vs. control children was not significantly different.

Dietary Intake Differences Between Obese and Normal Weight Children

Boys and Girls
In this study, the only food that showed a statistically significant (p<0.05) difference in intake between obese and normal weight youth was fruit juice (2.38±1.42 servings for obese children, 1.41±1.15 servings for normal weight children, p=0.01.)

Girls Only
Obese girls tended to consume more legumes (p=0.07) and dairy products (2.62±1.05 servings for obese, 4.01±2.14 for normal weight, p=0.054) than normal weight children. This represented a significant negative correlation between the intake of dairy products and BMI (r=-0.38, p=0.03). This resulted in a significantly lower intake of calcium and vitamin D in obese girls compared with nonobese girls.

Boys Only
Fruit juice consumption was significantly higher in obese than in nonobese boys (2.20±1.23 servings for obese, 0.99±0.81 servings for normal weight, p=0.01). The correlation between fruit juice consumption and BMI was statistically significant (r=0.49, p=0.02).

The difference in the percentage of energy from saturated fat was marginally higher in boys (15.5% vs. 13.0%, p=0.08).

Physical Activity Differences Between Obese and Normal Weight Children

Boys and Girls
Obese children performed lower levels of physical activity in the cold season compared with controls (p=0.01), and marginally lower levels in the warm season (p=0.07).

Girls Only
Normal weight girls were significantly (p=0.04) more active in the warm season than obese girls.

Boys Only
Normal weight boys were significantly (p=0.04) more active in the cold season than obese boys.

Author Conclusion:
  • In this study, the data did not support the hypothesis that obese children live in more food-insecure households and for this reason may consume a diet high in energy and low in nutrient-dense foods such as fresh fruits and vegetables.
Funding Source:
Government: USDA
Reviewer Comments:
  • Sample size calculations done based on dietary fat; power not achieved for girls (met 70% of target n)
  • Limited generalizability (convenience sample)
  • Did not assess fluctuations in food availability.
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? 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? 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? No
  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%.) N/A
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? N/A
  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? 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? 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? 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? No
  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? 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)? 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? Yes
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