EAL

PWM: Foods and Nutrients (2006)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To examine total beverage consumption among children and adolescents
To examine their beverage choices
To understand the relationships b/t beverage consumption & choice as influenced by age, gender, race/ethnicity, and BMI (i.e. body size)

Inclusion Criteria:

Not specified, but sample selected in such a way as to be U.S. nationally representative of all non-institutionalized individuals over 2 y old (refer to previous publication).

Exclusion Criteria:

not specified

Description of Study Protocol:

Analysis of USDA’s CSFII 1994-1996, 1998 data.

Multivariate regression analyses used to model consumption of individual beverage types as a function of gender, age, race, and BMI

Data Collection Summary:

(no blinding)

Dependent variables

total non-water beverage intake in grams (fluid milk, fruit drinks/ades (regular and diet), carbonated soft drinks (regular and diet), citrus juice, non-citrus juice; excluded alcoholic beverages, coffee, tea, liquids as part of meal (e.g., soups, meal replacements) (method not specified but known to be 24-hour recall)

Independent variables

BMI (as continuous variable)
BMI as dichotomous (< or > 85^th percentile using CDC stds)
Age
Ethnicity
Family income

Control variables

Gender (separate models)
Since age, ethnicity, family income included in multivariate models with BMI can consider control variables

Statistics

ANOVA with post-hoc multiple comparisons used to assess diffs in mean beverage consumption as influence by ethnicity.
Multivariate regression analysis used to model consumption of individual beverage types as a function of gender, age, ethnicity and BMI

Description of Actual Data Sample:

1687 boys
1624 girls
3311 total
(6-19 y)
(64% white, 15% black, 16% Hispanic, 5% other)

Summary of Results:

Bivariate analysis

AGE - older drink more beverages than younger
GENDER - males > females
ETHNICITY:

Children: White male children > blacks, but not Hispanics; no difference for girls
Adolescents: White males > blacks or Hispanics; white females > blacks, but not Hispanics

CHOICES:

Children: milk > soda > fruitade > citrus > non-citrus
Adolescents: soda > milk > fruitade > citrus > non-citrus
Heaviest milk drinkers are white and Hispanic boys; Lowest are female adolescents and blacks
Heaviest soda drinkers are white adolescent males; lowest are children

Multivariate Analyses

RELATION WITH BMI AS CONTINUOUS:
Males – positive with diet soda (unstandardized regression coef =1.6; t-ratio =1.99, p<.05)

Note: in discussion of results say no relation with diet soda so error in table?

Females – positive with diet soda (2.8 (2.42), p<.05); negative with milk (-4.2 (-3.69), p<.05)
For females each point of BMI is associated with 4 g fewer milk cons & 3 g more diet carbonated soft drink cons. These predicted associations amount to about one-tenth of an ounce per BMI point.
RELATION WITH BMI AS DICHOTOMOUS:

Males – with BMI > 85^th percentile consumed 12 g (0.4 oz) more diet carbonated soft drinks and 12 g more non-citrus juice

Note: in abstract say citrus juice negatively associated with BMI so error here?

Females – with BMI > 85^th percentile consumed 24 g less milk

OTHER RESULTS:

Ethnicity – Blacks drink less milk and soda, but more fruit drinks than whites (even after controlling for income)
Family income – little association with beverages; higher income slightly more diet carbonated soft drinks, higher income boys slightly more citrus/non-citrus

Author Conclusion:

Results: BMI has little or no association with beverage cons in these models. Heavier individuals do not drink more beverages than lighter individuals. After controlling for age, race/ethnicity, and family income, BMI has no statistically sig relation with any of the beverages for boys. For girls, BMI has a slight neg assoc with milk cons & a slight pos assoc with cons of diet carbonated soft drinks.

Abstract: BMI is positively associated with cons of diet carbonated beverages and negatively associated with consumption of citrus juice. BMI was not associated with cons of milk, reg carbonated beverages, reg or diet fruit drinks/ades, or non-citrus juices. In conc, total beverage cons and bev choices are strongly related to age, race, and gender. BMI was only related to consumption of diet carbonated beverages and milk, and those relationship were weak.

Note: Prelim research that we reported showed that children above 85^th percentile of BMI consumed about 2 oz more of total carbonated soft dinks that did those below 84^th. That preliminary research had several limitations that have been improved in this version. Most importantly, at the time that research was presented, age-specific BMI guidelines were not available, so the 85^th percentile for age ranges was used. Since age, BMI a, and total carbonated soft drink cons are all pos correlated, a disproportionate number of the children above the 84^th percentile were older children, some of whom would not be above the 85^th percentile using the new, age-specific guidelines. A second important limitation of the earlier research is that id did not disaggregate total carbonated soft drink consumption into reg & diet.

Funding Source:

Industry:

National Soft Drink Association

Commodity Group:

Reviewer Comments:

Strengths: Nationally representative & large sample size; examined numerous beverages

Weaknesses: Details on methods of measure not provided, results in text differ from table (4), BMI known to be based on self-report, no exclusion criteria provided, did not sum total sweetened beverages, did not sum total dairy, did not sum total juice, discrepancy b/t juice results (non-citrus vs citrus; neg vs pos assoc) in results and abstract; no control for physical activity.

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)	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?	No
	2.2.	Were criteria applied equally to all study groups?	Yes
	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?		???
	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?		No
	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?		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?	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?		No
	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?		No
	10.1.	Were sources of funding and investigators' affiliations described?	Yes
	10.2.	Was the study free from apparent conflict of interest?	No