AWM: Eating Frequency and Patterns (2013)
Recruitment Previously reported
Design Data was used form the NHANES I (1971-75) and NHANES I Epidemiologic Follow-up Study (1982-84) (NHEFS).
Blinding used (if applicable) NA
Intervention (if applicable) NA
Statistical Analysis regression analyses
Timing of Measurements 2 times, in 1971-75 and 1982-84
Dependent Variables
- weight change
Independent Variables
- frequency of eating occasion (entered as a continuous and categorical variable)- frequency of eating occasions was estimated by summing the energy yielding consumption reported at one time using a single 24-hour recall at Time 1. Occasions when non-caloric intake was reported was not counted. At follow-up respondents were asked one question each regarding the number of meals and number of snacks consumed daily and weight was measured.
Control Variables
- race
- education (<12, 12, >12 years)
- smoking status (never, former, current)
- age
- baseline BMI
- length of follow-up
- energy intake - 1 24-hour recall
- alcohol (0, <9.35 g, > 9.35 g)
- special diet status (yes or no)
- parity
- self-reported physical activity at baseline and follow-up (a lot, moderate, and little)
- presence of physician confirmed morbidty (0=no, 1=1 positive response, 2=2 positive responsed, and 3 >3 positive responses)
Initial N:For NHANES I: 14,407, for NHEFS 10,424
Attrition (final N): 7141 (large numbers were excluded for missing or unreliable data). Resulting n is 68% of eligible cohort of 10,424. 2580 men, 4567 women
Age: men=44.5 years, women = 45.9 years
Ethnicity: not reported
Other relevant demographics: Not reported for entire sample. Although 68% of the original smple was used for analysis, this sub-sample was similar to the original cohort in terms of age, eating frequency, baseline BMI, and energy intake.
Anthropometrics not reported for entire sample
Location: U.S.
Summary of Results (all Ps<0.05 unless otherwise reported):
- Mean weight change ranged between 1.88 to 2.66 kg (3.96 to 5.85 lbs) for men and 2.06 to 2.98 kg (4.56 to 6.56 lb) in women.
- In women, mean baseline BMI, triceps skinfold, suscapular skinfold, and plasma cholesterol, decreased with increasing baseline frequency of eating occasions (P<0.006).
- In men, mean baseline BMI and subscapular skinfold decreased with increasing baseline eating frequency; trends in triceps skinfold and plasma cholesterol were not consistent.
- Mean dietary energy and alcohol intake increased with increasing baseline eating frequency in both men and women.
- At follow-up, the highest eating frequency category (>6/d) was associated with largest mean weight change and baseline BMI in women, but not men.
- Mean plasma cholesterol at baseline was inversely associated with frequency of eating at follow-up in women but not men.
- Mean plasma cholesterol measured at baseline was inversely associated with frequency of eating at follow-up in women but not men.
- For every unit increase in frequency of eating at baseline, men and women gained 0.22 kg (.48 lbs) (P=0.03) and 0.34 kg (.75 lbs) (P=0.0002) of body weight, respectively, over the period of follow-up. After adjustment for age, and other confounders, this relationship was no longer significant.
- Re-analyzing data excluding persons reporting being on a special diet did not change the pattern of results.
There was no independent association of frequency of food ingestion estimated from a 24-h dietary recall with prospective weight change or frequency of eating estimated from answers to questions on number of meals and snacks consumed daily with weight change over the preceding 8-10 years in the NHEFS cohort.
Government: | National Cancer Institute |
University/Hospital: | Queens College of City University of New York |
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) | 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 | |
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? | ??? | |
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? | 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? | 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.) | Yes | |
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%.) | No | |
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 | |
4.5. | 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? | 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.) | 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? | 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? | 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? | 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? | No | |
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? | 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? | 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 | |