EAL

PWM: Eating Behaviors of Children (2006)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To examine the effect of SES, age, Weight and gender on the body image and weight control practices of children and adolescents, and to investigate whether health education about weight issues should target low socioeconomic groups.

Inclusion Criteria:

not specified

Exclusion Criteria:

Absent at initial and follow-up visits

Description of Study Protocol:

Recruitment –12 primary and secondary schools (8 public, 2 private, 2 Catholic) randomly selected from a list of all schools in the state and class groups of participants were randomly selected from school class lists.

Design – Students completed a questionnaire during regular class time and had height and weight measured in a private room.

Statistical Analysis –

X² – test differences in categorical variables
Backward elimination used to develop (separate) hierarchical log-linear models of relationship between gender, SES, age group, overwt category and dichotomous variables as follows: 1) body image, 2) lose wt, 3) gain wt, 4) skipping breakfast, 5) advised about good eating habits, 6) advised about bad eating habits, 7) advised about wt control.
MANOVA to evaluate relationship between gender, SES, age group and overwt category and self-esteem scores.
Univariate F-values were tested for significance at adjusted (Bonferroni) a levels to maintain a< 0.05 for each set of analyses.

Data Collection Summary:

(no blinding)

Dependent variables

Overweight based on BMI (measured wt/ht) >85^th percentile (Hammer, 1991)

Independent variables

Breakfast consumption on most days (Y/N)

Other variables modeled (questionnaire)

Body image (too fat, about right, too thin)
Trying to lose wt (Y/N)
Trying to gain wt (Y/N)
Morning tea on most days (Y/N)
Lunch on most days (Y/N
Afternoon tea on most days (Y/N)
Dinner on most days (Y/N)
Supper on most days (Y/N)
Self-esteem (Physical Self-Esteem score from 1-10; Abraham, 1999)
Advice on weight
Advice on eating habits
Sources of advise

Control variables

Gender
Age
SES (not a factor in breakfast skipping models)

Description of Actual Data Sample:

N: 1126 (521 males, 605 females)

Participation rate 88% after several follow-up visits to schools where participants had been absent on the first visit (therefore initial sample ˜1280)

Age: 6-19 y (mean 12.8 y)

Ethnicity: not specified

Other demographics: 26% (n=281) were low SES (from 3 schools in which majority of family incomes <20th percentile of income in the state), 17.2% (n=193) overweight)

Location: New South Wales, Australia

Summary of Results:

Breakfast skipping – 3 way interaction with gender, weight, age

Overweight females most likely to skip breakfast (18%) and normal weight males least likely to skip meals (10%)
Not clear if statistical difference in breakfast skipping between overweight and normal weight females and overweight and normal weight males
Female breakfast skippers: 9% overwt and 8% normal weight 6-12 yo; 26% overweight and 24% normal wt 12-19 yo
Male breakfast skippers: 14% overweight and 9% normal weight 6-12 yo; 20% overweight and 12% normal weight 12-19 yo
Older children of low SES more likely to skip breakfast (31%) than those of middle/high SES (22%)
Older females (25%) more likely than older males (16%) to skip breakfast

See paper for additional details on the following results:

SES

lower SES associated with overweight (˜2 times prevalence than middle/high SES)

Body image

Report being ‘too thin’ - overweight low SES > overwt middle/high
Older females more likely to report being ‘too fat’ and older males more likely to report being ‘too thin’

Weight control

Trying to gain weight - low SES females > middle/upper SES females; older males > older females; overweight males > overweight females
Trying to lose weight - overweight females > overweight males; older overweight > younger overweight

Advice about weight control and eating habits

Advised eating habits good -middle/upper SES > low SES males; young overweight middle/upper SES > young overweight low SES
Advised eating habits bad – young middle/high SES least likely and older middle/high SES most likely; young overweight males < females and normal weight peers
Advised to lose weight – young overweight females most likely and older normal weight males least likely

Physical self-esteem scores

Overwt low SES > overwt middle/high SES
Males > females
Normal weight females > overweight females

Author Conclusion:

Low SES children were more likely to be overweight, to skip breakfast, to perceive themselves as ‘too thin’, to be trying to gain weight and less likely to receive dietary or weight control advice.

Physical self-esteem was lowest among overweight girls of middle/upper SES and greatest among boys of low SES, despite the latter being more likely to be overweight. Being overweight does not appear to adversely affect the physical self-esteem of children of low SES, particularly boys.

Funding Source:

Industry:

Kellogg Australia

Food Company:

University/Hospital:

University of Sydney, University of Wollongong (Australia)

Reviewer Comments:

Strengths: Random sample; multivariate analysis.

Weaknesses:

No comparison of those included vs. not included in the study (due to absence)
subject SES defined on the basis of school rather than personal data which may result in misclassification
abstract says n=1131 which does not agree with text and tables
unknown ethnicity
no inclusion/exclusion criteria
BMI cutoffs not routinely used, limiting comparison with other studies.

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?		No
	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?	No
	2.2.	Were criteria applied equally to all study groups?	N/A
	2.3.	Were health, demographics, and other characteristics of subjects described?	No
	2.4.	Were the subjects/patients a representative sample of the relevant population?	???
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)	Yes
	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?	???
	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.)	No
	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?		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?	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?	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?	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?	No
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