AWM: Eating Frequency and Patterns (2013)
To test whether individual eating styles are associated with overweight and obesity in a population sample of young adult twins and a sub-sample of monozygotic twins.
- Paraticipants in the FinnTwin16 study
- 16 years old at baseline.
Individuals with self-reported:
- Weight-affecting diseases
- Anorexia and bulimia nervosa
- Inflammatory bowel disease
- Chronic diarrhea
- Celiac disease
- Hypo- or hyperthyroidism
- Mental retardation
- Cerebral palsy
- Other mobility disorders.
Participants were recruited for the FinnTwin16 study. Recruitment methods were not outlined.
Prospective cohort study.
- Differences between eating styles and BMI and overweight/obesity categories were investigated using cross-tabulations, Pearson χ² test of independence and linear and logistic regression, all corrected for clustered sampling within twin pairs
- The relationship of categorical BMI at T4 and eating styles at T4 was assessed using polytomous logistic regression models, controlling for BMI at T1 and correcting for clustered sampling
- In twin analysis, Pearson and polychoric correlation coefficients were computed to assess intra-pair twin resemblance by zyosity group. Monozygotic twin pairs were compared using conditional logistic regression.
Timing of Measurements:
- Participants were assessed at baseline or T1 (16 years), age 17 (T2), 18.5 years (T3) and 22 to 27 years (T4) of age
- Data from responses at T1 and T4 were used in this study
- T1 was between 1991 and 1995
- Data was collected at T4 between 2000 and 2002.
BMI was calculated based on self-reported weight and height. Weight status was categorized based on BMI as follows:
- Normal weight: BMI less than 25kg/m2
- Mild overweight: BMI 25 to less than 27kg/m2
- Moderate overweight: BMI 27 to less than 30kg/m2
- Obesity: BMI 30kg/m2 or higher.
- Eating styles as self-reported on questionnaire that assessed restrictive/overeating, snacking, health-conscious, emotional, and externally induced eating styles.
- Participants were asked to choose the one of four options that best characterized their eating styles.
Zygosity: Twins zygosity was determined by the baseline questionnaire and, when necessary, supplemented with photographs, fingerprints and DNA-marker studies. Twin pairs were classified as monozygotic, dizygotic or unknown zygosity.
- Initial N: 4,667 individuals (2,545 women and 2,122 men) were enrolled at baseline (T1)
- Attrition (final N): 4,393 individuals (2,333 women and 2,060 men) completed the study.
- 251 participants were excluded from the final data analysis because of exclusion factors identified at T4
- 23 individuals were excluded due to missing data on BMI at T4
- The sub-sample of monozygous twins included 358 female and 242 male twin pairs
- Age: 16 years at baseline
- Anthropometrics: BMI of the study population at baseline was not reported
- Location: Finland.
- Restrictive eating, overeating and alternating restricting/overeating at T4 were significantly more common in women than in men (P<0.0001) and significantly more common in obese than non-obese (P<0.0001)
- At T4, there was a lower likelihood of attempting to maintain a healthy eating style in overweight [mild overweight: OR women=0.6 (0.4 to 0.9, P<0.01); OR men=0.8 (0.6 to 1.0); moderate overweight: OR women= 0.4 (0.2 to 0.7, P<0.001); OR men=0.5 (0.4 to 0.7, P<0.001)] and obese [OR women=0.2 (0.1 to 0.3, P<0.001); OR men=0.4 (0.2 to 0.7, P<0.0001)] individuals compared to their normal-weight peers
- Restrictive eating, frequent snacking between meals, consuming food and snacks in the evening and avoiding fatty foods were associated with obesity in both men and women
- Both obese women (OR=4.4, 95% CI: 1.3 to 14.1, P<0.05) and overweight (OR=3.2, 95% CI: 1.3 to 7.9) men were significantly more likely to be prompted to eat by visual cues than their normal-weight peers
- When all eating styles were entered into a multi-variable model predicting obesity, controlling for gender and BMI at T1, restricting/overeating eating style at T4 was associated with obesity at T4 (OR=3.4, 95% CI: 2.2 to 5.3, P<0.001) and health-conscious eating style at T4 decreased the risk of obesity at T4 (OR=0.9, 95% CI: 0.8 to 1.0, P<0.01)
- When controlled for genetic background, restricting/overeating eating style was still statistically significantly associated with excess weight.
The Association of Regular, Restrictive and Overeating Eating Styles with Obesity
|Regular Eating||Restrictive Eating||Frequent Overeating||Alternating Restricting/Overeating|
Obesity is defined at BMI 30 or more.
The Association of Obesity and Eating Styles at T4, Adjusted for BMI at T1; Odds Ratios from the Best-fitting Multi-variable Logistic Regression Model
|Odds Ratio (95% CI)|
|Restrictive eating||3.4 (2.2 to 5.3)||<0.001|
|Frequent overeating||1.7 (0.9 to 3.4)|
|Alternating overeating and restricting||2.6 (1.1 to 6.4)|
|Health-conscious eating||0.9 (0.8 to 1.0)||<0.01|
|BMI at 16 years||1.8 (1.7 to 1.9)||<0.001|
Intra-pair Twin Correlations of BMI and Eating Styles by Twin Zygosity
|Same-sex Twin Pairs||Opposite-sex Twin Pairs
|BMI at T1||0.89||0.37||0.78||0.40||0.29|
|BMI at T4||0.79||0.42||0.79||0.26||0.24|
|Frequent snacking between meals||0.31||0.03||0.40||0.16||0.22|
|Frequent snacks replace meals||0.45||0.33||0.36||0.23||0.00|
|Highest food consumption in the evening||0.44||0.29||0.51||0.34||0.14|
|Grazing throughout the evening||0.45||0.17||0.40||0.16||0.22|
|Eating while watching TV||0.45||0.29||0.51||0.34||0.29|
|Avoiding fatty foods||0.54||0.09||0.41||0.29||0.18|
|Visual cues prompt eating||0.49||0.37||*||*||*|
|Food used as a reward||0.40||0.15||0.24||0.29||0.14|
*Intra-pair correlation could not be computed because no twin pair was concordant for the presence of this trait.
**Only complete twin pairs of known zygosity who did not have chronic weight-affecting illnesses were included in the analysis (N=1,799 pairs).
- The authors conclude that eating styles of obese young adults differ markedly from their normal weight counterparts, with clear sex differences. Patterns of restrictive eating, overeating and alternating restrictive/overeating were most commonly associated with obesity.
- According to the authors, this study also implies that a genetic pre-disposition alone does not dictate body weight, but that environmentally influenced behavioral behavior patterns, such as eating styles and healthful eating choices, also make a difference.
|Government:||European Union Frfty Framework Program, Academy of Finalnd|
|University/Hospital:||Helsinki University Central Hospital|
- To identify healthy eating styles, an 11-item questionnaire was used. Five questions assessed snacking/grazing styles, three addressed health-conscious eating, two addressed emotional eating, and one addressed externally cued eating
- The data was based only on self-reported information and is subject to reporting error
- BMI was self-reported and subject to reporting error.
Quality Criteria Checklist: Primary Research
|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)||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|
|4.||Is the intervention or procedure feasible? (NA for some epidemiological studies)||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|
|1.2.||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?||???|
|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?||No|
|2.4.||Were the subjects/patients a representative sample of the relevant population?||???|
|3.||Were study groups comparable?||???|
|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?||???|
|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?||Yes|
|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?||???|
|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?||Yes|
|6.3.||Was the intensity and duration of the intervention or exposure factor sufficient to produce a meaningful effect?||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|
|6.6.||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?||Yes|
|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?||???|
|7.1.||Were primary and secondary endpoints described and relevant to the question?||Yes|
|7.2.||Were nutrition measures appropriate to question and outcomes of concern?||N/A|
|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?||No|
|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?||N/A|
|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|