EAL

NGHC: Childhood Nutrition and Lifestyle Factors (2013)

Citation:

Study Design:

Class:

- Click here for explanation of classification scheme.

Quality Rating:

Research Purpose:

To examine whether increases in adolescent television viewing time are associated with increases in total energy intake and whether viewing increases are also associated with increases in intake of candy, fast food, fried potatoes, sweet baked snacks, salty snacks and sugar sweetened beverages.

Inclusion Criteria:

Students at five schools in the Boston, Massachusetts area assigned as control schools in the Planet Health intervention between the fall of 1995 and spring of 1997
Students in grade six and grade seven during baseline measurement and in grade seven and grade eight during follow-up measurement.

Exclusion Criteria:

Student transferred schools during the study period
Students in special education classes
Students in grades other than six or seven at baseline
Students that did not complete the English-language version of the questionnaire
Student reporting implausible daily energy intakes (less than 500kcal per day or greater than 7,000kcal per day).

Description of Study Protocol:

Recruitment

Students attending Planet Health intervention control schools, in grades six and seven during baseline, were asked to complete a questionnaire under the supervision of trained teachers.

Design

Before and after study

Blinding used

None

Intervention

None, were Planet Health intervention control schools

Statistical Analysis

Adjusted associations of change in television viewing with change in total energy intake were estimated in a series of regression models. Predictor variables in each model included baseline television viewing and change in viewing, baseline BMI, total energy intake, age, gender, indicator variables for race and ethnicity, baseline physical activity and change in physical activity and indicator variables for school.

Data Collection Summary:

Timing of Measurements

Baseline questionnaires were completed in the fall of 1995 and follow-up questionnaires were completed in the spring of 1997.

Dependent Variables

Total energy intake at baseline
Change in total energy intake at follow-up
Change in intake of foods commonly advertised on television at follow-up.

Independent Variables

Baseline television viewing
Change in television viewing at follow-up.

Control Variables

Baseline BMI
Age
Gender
Indicator variables for race/ethnicity
Baseline physical activity and change in physical activity at follow-up
School.

Description of Actual Data Sample:

Initial N: 548 students (48.4% female)
Attrition (final N): 548 students
Age: 11.7±0.75 years at baseline
Ethnicity:
- 63.5% white
- 15.3% Hispanic
- 13.9% African American
- 7.7% other ethnicity (some students selected more than one race/ethnicity)
Other relevant demographics: Average household income at schools selected was $34,200 per year in 1995; lower than Massachusetts average ($41,000 per year) but similar to US average ($33,952 per year)
Anthropometrics: Baseline BMI measured, but not reported
Location: Boston, Massachusetts, USA.

Summary of Results:

Key Findings

Food serving changes

Mean additional servings of food commonly advertised on TV (baked sweet snacks, candy, fast food-type main courses, fried potatoes, salty snacks, and sugar-sweetened beverages) were associated with hours of baseline television viewing and with additional hours of television viewing at follow-up
Adjusted change in servings per day of foods commonly advertised on television associated with baseline television viewing and additional hours of television viewing at follow-up:

Food	Additional Servings per Day at Follow-Up Associated with Each Hour of Baseline TV Viewing	Additional Servings per Day at Follow-Up Associated with Each Hour Increase in TV Viewing
Baked sweet snacks	0.21 (95% CI 0.08-0.33; P=0.01)	0.21 (95% CI 0.14-0.29; P=0.002)
Candy	0.06 (95% CI 0.03-0.10; P=0.006)	0.08 (95% CI 0.02-0.14; P=0.02)
Fast Food Entrees	0.06 (95% CI 0.04-0.08; P=0.001)	0.09 (95% CI 0.06-0.12; P=0.001)
Fried potatoes	0.02 (95% CI -0.004-0.04; P=0.08)	0.03 (95% CI 0.01-0.04; P=0.004)
Salty snacks	0.06 (95% CI 0.01-0.12; P=0.04)	0.09 (95% CI 0.04-0.14; P=0.009)
Sugar-Sweetened Beverages	0.14 (95% CI 0.12-0.16; P=<0.001)	0.11 (95% CI 0.01-0.22; P=0.04)
All foods	0.54 (95% CI 0.37-0.72; P=0.001)	0.60 (95% CI 0.41-0.78; P=0.001)

Energy intake changes

Baseline television viewing predicted total energy intake at follow-up with each hour of television viewing at baseline associated with a mean additional intake of 127kcal (95% CI, 27.7kcal to 226.2kcal; P=0.02)
Each hour increase in television viewing from baseline to follow-up was associated with a 167kcal increase in daily energy intake (95% CI, 135.9kcal to 197.9kcal; P=<0.001)
After adjusting for baseline covariates, each hour increase in television viewing was associated with an additional 167kcal per day (95% confidence interval, 136kcal to 198kcal per day; P<0.001) and with increases in the consumption of foods commonly advertised on television
When specific foods were entered into the model, the coefficients for television viewing were greatly reduced (baked sweet snacks, candy, fried potatoes, salty snacks and sugar-sweetened beverages) or rendered insignificant (fast food main entrees).

Author Conclusion:

Increases in television viewing are associated with increased calorie intake among youth. This association is mediated by increasing consumption of calorie-dense low-nutrient foods frequently advertised on television.

Funding Source:

Government:

National Institute of Child Health and Human Development; Centers for Disease Control and Prevention; National Institutes of Diabetes and Digestive and Kidney Diseases

Not-for-profit

Charles H Hood Foundation, Boston, MA, USA

Other non-profit:

Reviewer Comments:

Paper published in 2006, but data from 1995-1997. Television viewing was the primary measure of "screen time" consistent with data published during this time period before Internet usage and computerized hand-held devices were used frequently. Video game exposure was not measured.
Food intake was assessed by self-reported food frequency data and television viewing time was also self-reported, introducing he possibility of recall error
Serving increases with each hour of baseline television viewing and each additional hour of television viewing at follow-up were small; all less than 1/4 increase in servings, most less than 1/10 increase in servings.

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?	Yes
	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?		Yes
	3.1.	Was the method of assigning subjects/patients to groups described and unbiased? (Method of randomization identified if RCT)	Yes
	3.2.	Were distribution of disease status, prognostic factors, and other factors (e.g., demographics) similar across study groups at baseline?	Yes
	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?	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?		???
	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?	???
	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?	Yes
	6.6.	Were extra or unplanned treatments described?	Yes
	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?		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?	Yes
	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?	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