PWM: Eating Behaviors of Children (2006)

Mikkila V, Lahti-Koski M, Pietinen P, Virtanen SM, Rimpela M. Associates of obesity and weight dissatisfaction among Finnish adolescents. Publ Health Nutr 2002;6:49-56.
Study Design:
Cross-Sectional Study
D - Click here for explanation of classification scheme.
Quality Rating:
Neutral NEUTRAL: See Quality Criteria Checklist below.
Research Purpose:
To describe the complex relationships between weight, weight perceptions and socio-economic and behavioral factors among Finnish adolescents.
Inclusion Criteria:
Not specified.
Exclusion Criteria:
  • Any students absent from class on day of questionnaire (91% response rate)
  • <14 or >16 years of age (5,663 students)
  • Giving obviously unreliable answers (141 students).
Description of Study Protocol:


  • Every borough in Finland invited to participate, but not all did (boroughs volunteered and therefore it was not a randomly selected sample)
  • All secondary schools in volunteering boroughs included
  • Subjects from the School Health Promotion Study, an annual assessment of the health and health behavior of Finnish schoolchildren.


  • Students completed a one-hour questionnaire on health, health behavior and SES background (1996 or 1997).

Statistical Analysis

  • Logistic regression to examine relationship of obesity and weight satisfaction with other variables (normal weight as reference for obesity comparison with underweight students excluded; those satisfied with weight as reference for weight satisfaction comparison with weight category controlled for)
  • ORs and 95% CIs computed for obesity status and weight dissatisfaction associated with SES and behavioral factors.
Data Collection Summary:
  • Blinding: None.

Independent Variables

  • Fast food intake (tertile of intake of factor characterized by hamburgers, hot dogs, meat pasties, pizza, soft drinks sweetened with sugar, crisps, chips and sweets).

Dependent Variables

  • Relative weight status: Underweight <80%, normal 80-120%, obesity >120% 
  • Relative weight defined as percentage of mean weight for sex and height within the sample (based on self-reported weight and height).

Other Variables

  • SES of family (questions on family structure, educational level of parents, and economic situation of family as perceived by student)
  • School performance (tertile of latest school report card grade relative to mean grades)
  • Exercise frequency (one question)
  • Use of alcohol (three questions)
  • Smoking (two questions)
  • Food behaviors
    • School lunch
    • Evening meal at home
    • 15-item FFQ, which besides fast food factor, also included healthy food factor (fruits, berries, rye bread, fresh vegetables, salad, yogurt) and traditional food factor (coffee, sweet buns, sausages)
  • Weight dissatisfaction (1 question).

Control variables

  • Gender (separate analysis)
  • Educational level of parents
  • Economic status of family
  • School performance
  • Physical exercise
  • Use of alcohol
  • School lunch
  • Evening meals at home.
Description of Actual Data Sample:


  • 60,252 (29,718 males, 30,534 females)
  • 75% of excluded were males.


  • 14-16 years.


  • Not specified.

Other Demographics

  • 77-78% had two-parent families
  • 52-58% had parents without a high school degree
  • 67-77% rated economic status of family good
  • Frequency of other variables measured also reported (see Table Two).


  • Finland.
Summary of Results:

Variables Significantly Associated with Obesity in Girls in Multivariate Model 

  • Low educational level of parents (parents without HS degree > one or more parents with HS degree)
  • Perceived economic problems (some or severe problems > good)
  • Low school performance (lowest tertile > middle and highest tertile)
  • No use of alcohol (non-user > occasional or regular user)
  • No evening meal at home (> evening meal at home daily with or without family)
  • Low fast food use (lowest tertile > middle and highest tertile).

Variables Significantly Associated with Obesity in Boys in Multivariate Model

  • Low educational level of parents
  • Perceived economic problems
  • Low school performance
  • Low physical activity (less than weekly > one to three, four to six or seven times per week
  • No school lunch (> daily school lunch while taking only bread, milk or salad < daily school lunch)
  • Low fast food use
  • Variables significantly associated with weight dissatisfaction
  • Use of fast food (for both girls and boys).
[Note: Others listed in Table Four.]
Author Conclusion:

Having normal weight and being satisfied with that weight are favorable for an adolescent. Obesity and weight dissatisfaction are associated mostly with disadvantageous health behaviors and low SES. Health behavior seems to be associated more with weight satisfaction than with actual weight.

Consistent with other studies, food behavior seemed to have stronger associations with weight satisfaction than with actual body weight. Not having evening meals at home was associated with obesity status in girls and with weight dissatisfaction in both sexes. Obese boys, as well as the girls and boys who were dissatisfied with their weight, reported eating school lunch less frequently than the others. This may suggest that the obese try to lose weight by skipping meals. 

Obese girls and boys reported consuming fast food less frequently than did their slimmer peers. Weight satisfaction was associated with eating fast food among both sexes and, among boys, also with eating health foods. The obese and those wanting to be thinner may, however, more often underreport the use of fast food. The negative labeling of ‘junk food,' thought to be unhealthy and fattening, may lead to both underreporting of its use and avoiding it in rapacity.
Funding Source:
Foundation associated with industry:
Reviewer Comments:


  • Large sample size
  • Multivariate model.


  • No comparison between students included and excluded
  • Convenience sample
  • Self-reported weight and height
  • Use of population-specific, but non-standard obesity definition.
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? N/A
  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? 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
  4.3. Were all enrolled subjects/patients (in the original sample) accounted for? Yes
  4.4. Were reasons for withdrawals similar across groups? No
  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? Yes
  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? No
  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? No
  7.5. Was the measurement of effect at an appropriate level of precision? No
  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? No
  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