Pediatric Weight Management

PWM: Physical Activity and Inactivity of Youth (2006)

Citation:

Brewis A. Biocultural aspects of obesity in young Mexican schoolchildren. Am J Hum Biol. 2003 May-Jun;15(3):446-60.

PubMed ID: 12704721
 
Study Design:
Descriptive Study
Class:
C - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:
  1. To report a study of biocultural aspects of obesity in a sample of 6 to 12 year old middle-class Mexican children,
  2. To identify general socio-economic features that may explain the particularly high rates of middle childhood obesity in a Mexican population characterized by relatively high SES,
  3. To investigate how individual socioeconomic variation (such as differences in exercise, diet, family, household, parental, and demographic factors) help explain within-population variations in risk of obesity in middle childhood in Mexico, and
  4. To consider how secular trends associated with such broad scale social change changes at a more proximate level.
Inclusion Criteria:
  • 6 to 12 year old children attending a single state elementary school in Jalapa (represents approximately half of the total study body).
  • Obese: BMI at or above the 95th percentile
Exclusion Criteria:
Not stated
Description of Study Protocol:

Design

Data sets were collected for each participating child. Interviews took place in a private room at school and were conducted by student teachers. Observational studies were made in school settings and in homes. Investigators observed foods being consumed during recess (n=1095 observations, in which 435 instances of food consumption were recorded). To make these observations, each child in the sample was located on 5 different occasions during recess, and whatever they were eating or drinking when first observed was recorded. Parent & child reports of number of soda drinks consumed in the preceding 7 days were also provided.

Statistical Analysis

T-tests (identify significant gender variations in mean anthropometric values), binary logistic regression (describing and testing hypothesis between obese and not obese groups and multiple continuous or categorical predictor variables).
Data Collection Summary:

Dependent Variables

  • Body mass index

  • Body fat (skinfold thickness and upper arm circumference)

Independent Variables

  • Demographic variables including gender, birth weight, infant
  • child feeding practices (age at weaning, soda consumption, sweet snack consumption),
  • parental factors (mother’s and father’s age at birth, mother’s and father’s education level, mother working or at home),
  • biobehavioral factors (hours of television viewing, computer use, reading, vigorous exercise),
  • family and household variables (size, membership, birth order, SES).

Family functioning is not analyzed separately by gender and strictness is rated by parent’s score on a 0-10 point disciplinary attitudes scale

Health variables including parent, teacher and child’s self reporting of anxiety, depression and self esteem, parent reports of child suffering from allergies or asthma, absence from school, visits to doctor, and parent, teacher, and classmate reports of popularity among peers and happiness

Control Variables

Not specified.

Description of Actual Data Sample:

Initial N: 219 (110 girls, 109 boys)

Attrition (final N): 219 (110 girls, 109 boys)

Age: 6 to 12 years

Ethnicity: Mexican

SES: Middle-class

Anthropometrics: 24.2% of all children in this sample were obese at baseline (29.4% boys and 19.1% girls).

Location: Jalapa, Mexico

Summary of Results:

Parents of these obese children classified them as having a weight problem only 58.9% of the time (63.6% boys, 52.9% girls). Just under 18% of all parents classified their children as having a weight problem.

Snacking frequency observations: Fruit is not described, but vegetables are called “vegetable snacks” and included jicama with chili powder, which was the most popular (n=11); “cookies and cakes” snacks (n=26); the most common candy items is lollipops (n=48 out of 92 candy observations); other snacks observed include bagged fried snacks are popcorn, Cheetos, and potato chips (n=51); savory snacks are high fat and include enchiladas, tamales, gorditas, hamburgers, hot dogs, and chicharrones (n=81).

Children spent an estimated average of 11.48 hour per week watching television, 2.76 hours on computers outside of school, 2.52 hours reading for pleasure, and 5.88 hours spent at vigorous exercise.

The majority of children were breastfed (84.6%). Mean age at weaning was 7.74 months.

Logistic regression model included three predictors explaining children’s classification as obese or non-obese:

  1. gender
  2. number of other children in the household
  3. parental strictness in disciplinary strategy

The log odds of a child being obese is negatively related to more children in the household (p<0.05), negatively related to gender--i.e., boys more likely than girls to be obese (p<0.05), and negatively related to the degree of strictness in the parental disciplinary strategy (p<0.05). The odds of a boy being obese are 2.33 times greater than the odds of a girl being obese.

Obese children showed no differences in social, mental, or physical aspects of well-being than their non-obese peers.

Author Conclusion:
The findings of this study allow some recognition of how large-scale secular trends in body size are mediated at the individual level. The finding that there are crucial microniche dynamics underlying gender differences in obesity risk indicated the importance of including a focus on gender as a socioeconomic construct in human biological studies of child growth, development and nutrition.
Funding Source:
University/Hospital: University of Georgia
Reviewer Comments:

Limitations:

Control variables not clearly indicated.

Rate of obesity is higher than other populations/regions. May not be generalizable to other regions, countries, or races.

Other Comments:

Cultural attitude: “chubby children are healthy children.”

Highest BMI was 31.45; only 1.5% had BMI > 30; no extreme degrees of obesity.

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
  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
  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
  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
  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. Was the research question clearly stated? Yes
  1.1. Was (were) the specific intervention(s) or procedure(s) [independent variable(s)] identified? 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
  1.2. Was (were) the outcome(s) [dependent variable(s)] clearly indicated? Yes
  1.3. Were the target population and setting specified? Yes
  1.3. Were the target population and setting specified? Yes
  2. Was the selection of study subjects/patients free from bias? 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
  2.1. 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
  2.2. Were criteria applied equally to all study groups? Yes
  2.3. Were health, demographics, and other characteristics of subjects described? 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? ???
  2.4. Were the subjects/patients a representative sample of the relevant population? ???
  3. Were study groups comparable? 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
  3.1. 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? Yes
  3.2. Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline? Yes
  3.3. Were concurrent controls or comparisons used? (Concurrent preferred over historical control or comparison groups.) 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
  3.4. 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
  3.5. 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
  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. Was method of handling withdrawals described? No
  4.1. Were follow-up methods described and the same for all groups? N/A
  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
  4.2. 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
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? N/A
  4.4. 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
  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? ???
5. Was blinding used to prevent introduction of bias? ???
  5.1. In intervention study, were subjects, clinicians/practitioners, and investigators blinded to treatment group, as appropriate? 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.) ???
  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.) ???
  5.3. In cohort study or cross-sectional study, were measurements of outcomes and risk factors blinded? 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
  5.4. 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
  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. 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
  6.1. 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
  6.2. 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
  6.3. 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? 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
  6.5. Were co-interventions (e.g., ancillary treatments, other therapies) described? N/A
  6.6. Were extra or unplanned treatments 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
  6.7. 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
  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? ???
7. Were outcomes clearly defined and the measurements valid and reliable? ???
  7.1. Were primary and secondary endpoints described and relevant to the question? 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? ???
  7.2. Were nutrition measures appropriate to question and outcomes of concern? ???
  7.3. Was the period of follow-up long enough for important outcome(s) to occur? N/A
  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? ???
  7.4. Were the observations and measurements based on standard, valid, and reliable data collection instruments/tests/procedures? ???
  7.5. Was the measurement of effect at an appropriate level of precision? 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
  7.6. Were other factors accounted for (measured) that could affect outcomes? Yes
  7.7. Were the measurements conducted consistently across groups? 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? ???
8. Was the statistical analysis appropriate for the study design and type of outcome indicators? ???
  8.1. Were statistical analyses adequately described and the results reported appropriately? 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
  8.2. 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
  8.3. 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
  8.4. 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)? No
  8.5. Were adequate adjustments made for effects of confounding factors that might have affected the outcomes (e.g., multivariate analyses)? No
  8.6. Was clinical significance as well as statistical significance reported? 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
  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? ???
9. Are conclusions supported by results with biases and limitations taken into consideration? ???
  9.1. Is there a discussion of findings? Yes
  9.1. Is there a discussion of findings? Yes
  9.2. Are biases and study limitations identified and discussed? No
  9.2. Are biases and study limitations identified and discussed? No
  10. Is bias due to study's funding or sponsorship unlikely? Yes
10. Is bias due to study's funding or sponsorship unlikely? Yes
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.1. Were sources of funding and investigators' affiliations described? Yes
  10.2. Was the study free from apparent conflict of interest? Yes
  10.2. Was the study free from apparent conflict of interest? Yes