PWM: Eating Behaviors of Children (2006)

Citation:
 
Study Design:
Class:
- Click here for explanation of classification scheme.
Quality Rating:
Research Purpose:
To assess the relationship between feeding pattern and body mass index in free-living humans.
Inclusion Criteria:
Not reported.
Exclusion Criteria:
Not reported.
Description of Study Protocol:

Dietary Intake

  • Assessed by 220 weighed seven-day food records. Daily energy intakes were divided into a maximum of six feeding periods: Breakfast, mid-morning snacks, lunch, mid-afternoon snacks, evening meal and evening snack. A feeding period was defined as the consumption of any food or beverage which provided energy. Two consecutive feeding occasions were considered separate if the time interval between them was greater or equal to one hour. Some of the young adults did not consume any food or beverage until midday at the weekend. In this case, the first feeding occasion of the day was classified as breakfast. On such days as this, energy intake at lunch was usually small and occasionally omitted.
  • For each individual, the mean energy intake at each feeding period, as a percentage of mean total energy intake (TDI), was calculated and named the percentage mean period energy intake (% MPEI).

Feeding pattern

  • Assessed by two methods: The feeding variability index and the feeding frequency index. "Gorgers" are defined as having a feeding frequency index between one and three. "Nibblers" are defined as having a feeding frequency index between four and six.

Validation of Energy Intake Data

  • The validity of recorded seven-day food records was assessed by calculating the mean physical activity level (PAL=reported energy intake/estimated basal metabolic rate), where basal metabolic rate was calculated from equations using age, sex, weight and height. PAL values below 1.10 were defined as invalid and those above 1.09 as valid.

Statistical analyses

  • One-way analysis of variance and Scheffe’s multiple comparison test. Correlation coefficient for the degree of linear relationship between feeding pattern and the validity of energy intake data. Linear regression for the degree of linear relationship between body mass index (BMI) and the feeding variability index, the feeding frequency index, energy intake at breakfast, energy intake during the evening and total daily energy intake (TDI). Unpaired T-test for differences in BMI between upper and lower tertiles of the feeding variability index, the feeding frequency index, energy intake at breakfast, energy intake during the evening and TDI.
Data Collection Summary:

Independent

  • Feeding pattern.

Dependent

  • Body mass index
  • Body composition
  • Body mass was assessed. No details on how this was done (described elsewhere).

Confounding

  • Not stated.
Description of Actual Data Sample:

N

  • 220 individuals.

Age

  • Four age groups:
    1. 33 adolescents, mean age 13 years (12 males and 21 females)
    2. 59 "working age" adults, mean age 31 years (29 males and 30 females);
    3. 40 'middle-aged" adults, mean age 48 years (six males and 34 females);
    4. 88 "elderly" adults, mean age 77 years (24 males and 64 females).

Ethnicity

  • Not discussed.

Location

  • England.
Summary of Results:

Results

  • A positive relationship between feeding pattern and BMI was observed in the Adolescent and Middle-Aged groups, but not in the Working Age or Elderly groups. In the Middle-Aged group, greater energy intakes at breakfast and lower energy intakes during the evening were associated with a lower BMI (P<0.05).
  • In the Adolescent group, a more even distribution of energy intake over the day ("nibblers") or a greater amount of energy consumed at breakfast were associated with lower BMIs (P<0.01). However, when invalid diet records (using PALS) were removed from the analysis, these relationships went away, except energy intakes consumed at breakfast remained inversely related to BMI in the Ad`olescent group (P<0.05). 
Author Conclusion:

The amount of energy consumed at breakfast by the Adolescent group was inversely related to BMI (P<0.05). The results indicated that a more even distribution of energy intake during the day or "nibbling" or a greater amount of energy consumed at breakfast was associated with a lower BMI (P<0.05). The authors suggested an explanation may be that adolescents may use omission of breakfast as a dieting strategy.

The authors also indicated that a more "gorging" type of feeding pattern was observed in the Adolescent, Middle-Aged and Elderly groups by individuals who produced invalid diet records. They  suggested that adolescent and middle-aged females who were overweight, dieting or highly restrained eaters may have under-reported their "habitual" energy intake, especially from snacks during the study period, thus producing diet records that indicated relatively low energy intakes and a "gorging" feeding pattern related to obesity.

Funding Source:
Other: no recorded funding
Reviewer Comments:
  • Dietary restraint or incidence of dieting were not assessed in this study.
  • Very confusing methodology with PALS and removing records as being “invalid” or “valid.”
  • Does not seem to work with under-reporting or "habitual" foods and snacks.
  • Under-reporting is a major issue.
  • Failure to control for potential confounders.
  • Ethnicity, inclusion, and exclusion criteria were not discussed.
  • Because study is conducted in England, limited generalizability.
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? No
  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? Yes
3. Were study groups comparable? 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? 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? 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%.) 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? 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? 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? No
  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? No
  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)? No
  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? No
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? ???