Two-Year Outcomes of the Enabling Mothers to Prevent Pediatric Obesity Through Web-Based Education and Reciprocal Determinism (EMPOWER) Randomized Control Trial

Abstract

Background. Childhood overweight and obesity is a public health epidemic with far-reaching medical, economic, and quality of life consequences. Brief, web-based interventions have received increased attention for their potential to combat childhood obesity. The purpose of our study was to evaluate a web-based, maternal-facilitated childhood obesity prevention intervention dubbed Enabling Mothers to Prevent Pediatric Obesity Through Web-Based Education and Reciprocal Determinism (EMPOWER), for its capacity to elicit sustained effects at the 2-year postintervention follow-up mark. Method. Two interventions were evaluated using a randomized controlled trial design. The experimental, EMPOWER arm received a social cognitive theory intervention (n = 29) designed to improve four maternal-facilitated behaviors in children (fruit and vegetable consumption, physical activity, sugar-free beverage intake, screen time). The active control arm received a knowledge-based intervention dubbed Healthy Lifestyles (n = 28), which also targeted the same four behaviors. Results. We identified a significant group-by-time interaction of small effect size for child fruit and vegetable consumption (p = .033; Cohen’s f = 0.139) in the EMPOWER group. The construct of maternal-facilitated environment was positively associated to improvements in child fruit and vegetable behavior. We also found significant main effects for child physical activity (p = .024; Cohen’s f = 0.124); sugar-free beverage intake (p < .001; Cohen’s f = 0.321); and screen time (p < .001; Cohen’s f = 0.303), suggesting both groups improved in these behaviors over time. Conclusions. The EMPOWER arm of the trial resulted in an overall increase of 1.680 daily cups of fruits and vegetables consumed by children, relative to the comparison group (p < .001, 95% confidence interval = [1.113, 2.248]). Web-based maternal-facilitated interventions can induce sustained effects on child behaviors.

Keywords

family-based prevention mother–child dyad obesity online intervention overweight social cognitive theory

Currently, one in three children are overweight or obese in the United States (Ogden, Carroll, Kit, & Flegal, 2014). Childhood obesity tracks into adolescence and adulthood, potentially leading to numerous endocrine, cardiovascular, gastrointestinal, pulmonary, orthopedic, neurologic, dermatologic, and psychosocial comorbidities (Klish, Kirkland, & Motil, 2015). Considering the deleterious consequences of childhood obesity, it is important to design and disseminate interventions to combat this epidemic. In the realm of health education and health promotion, interventions have attempted to prevent and treat childhood obesity in a variety of environmental contexts including communities, schools, and primary care settings (Economos et al., 2007; Hollar et al., 2010; Taveras et al., 2011).

More recently, there has been increased calls for additional delivery of interventions within the family-and-home environment (Golan & Crow, 2004). Parents are powerful change agents in the lives of their children, particularly at younger ages (Robinson et al., 2015). Nevertheless, interventions targeting the family-and-home environment for childhood obesity face a number of barriers, including a significant time commitment from parents (Knowlden & Sharma, 2012a). In light of these barriers, web-based interventions have been suggested as a mechanism to deliver educational materials (Knowlden & Sharma, 2012a). Ideally, such interventions would be brief, theory based, and elicit sustainable changes. Within this context, we designed, implemented, and evaluated two brief, maternal-facilitated, web-based interventions for the prevention of childhood obesity (Knowlden, Sharma, Cottrell, Wilson, & Johnson, 2015).

Method

Study Design

The Enabling Mothers to Prevent Pediatric Obesity through Web-Based Education and Reciprocal Determinism (EMPOWER) was an equally allocated (1:1), parallel-group, randomized, active-controlled, participant-blinded, superiority trial. EMPOWER was implemented between March and May of 2013. EMPOWER was hosted on an online platform at the University of Cincinnati (Ohio). There were no major deviations from the EMPOWER protocol we published prior to initiating the trial (Knowlden & Sharma, 2012b).

Participants

We recruited a single cohort of 57 participants in February 2013 using flyers and posters displayed in day cares, child care centers, and health organizations in the Cincinnati, Ohio, region. Participation in EMPOWER was limited to English-speaking mothers, 18 years and older, with at least one child between 4 and 6 years of age. For those mothers with more than one child between 4 and 6 years of age, we requested they completed the study with their oldest child in mind. We excluded participants from the trial if they failed to meet the inclusion criteria, did not provide consent, or if their child: had a disability prohibiting them from engaging in daily physical activity, were prescribed medication with the potential to cause weight loss or gain, were enrolled in another other type of weight management program. As we implemented the intervention online, participants were required to have Internet access, a valid e-mail address, and a valid telephone number. As we did not provide computer training, we required participants enroll in the intervention online.

Before enrolling in the trial, we requested participants review and sign an institutional review board (IRB)–approved consent form. We randomly allocated consenting participants to receive either the experimental (EMPOWER) intervention or active control (Healthy Lifestyles) intervention. We incorporated single-blinding to reduce the potential for cross-contamination. We used a random group generator programmed into Microsoft Excel 2010 to randomize participants to either the experimental or active control arms of the trail. The principal investigator conducted the randomization procedure and assigned participants to the interventions.

Interventions

We designed and implemented two new interventions to enrolled participants of the EMPOWER trial. We provided details of both interventions in previous publications (Knowlden & Sharma, 2012b; Knowlden et al., 2015). In brief, the experimental EMPOWER intervention was a theory-based program designed to actualize five constructs of social cognitive theory (environment, emotional coping, expectations, self-control, and self-efficacy) in participating mothers to improve four behaviors (fruit and vegetable consumption, physical activity, sugar-free beverage intake, reduced screen time) in their children. Alternatively, the active control Healthy Lifestyles intervention was a knowledge-based program designed to provide information about the same four behaviors to participants.

We used the same educational modalities in both interventions including 10- to 15-minute audiovisual presentations, interactive worksheets, and online discussion board postings. Both interventions contained a total of five modules, with one module dedicated to each of the four child behaviors. We delivered a fifth, booster session 2 weeks after the intervention was over (Week 6). We designed the booster session to reinforce the content of the previous four modules. The salient difference between the programs was that Healthy Lifestyles focused on providing information about the behaviors, whereas the EMPOWER intervention included maternal-facilitated social cognitive theory-based strategies to change the four child behaviors.

Outcome Variables

Our outcome variables included four child behaviors associated with prevention of childhood obesity: (a) daily consumption of five cups of fruits and vegetables, (b) 120 total minutes of daily structured and unstructured of physical activity, (c) increase in sugar-free beverage intake, (d) limitation of screen time (sedentary time spent in front of a television, computer screen, or portable electronic device) to no more than 120 minutes per day (Clark et al., 2002; Rao, 2008). Our second set of outcome variables included scores on five maternal-facilitated social cognitive theory constructs: (a) environment, (b) emotional coping, (c) expectations, (d) self-control, (e) and self-efficacy (Arredondo et al., 2006; Bandura, 2001, 2004, 2006; Baranowski, Cullen, Nicklas, Thompson, & Baranowski, 2003; Birch, 1998; Corwin, Sargent, Rheaume, & Saunders, 1999; Galloway, Fiorito, Francis, & Birch, 2006). We hypothesized the EMPOWER intervention would improve the scores for the five maternal-facilitated social cognitive theory constructs leading to improvements in the four child behaviors.

Measurement

We developed an instrument to evaluate the efficacy of the EMPOWER trial (Knowlden & Sharma, 2015). We collected data for the EMPOWER measurement tool from a separate, convenience sample of mothers (n = 224) matching the EMPOWER inclusion criteria prior to the start of the trial. Our procedures for instrumentation included operationalizing the outcome variables measured in the EMPOWER trial; determining face and content validity of the instrument via a panel of six experts over two rounds; conducting test–retest of the instrument by having a subset of the participants (n = 31) complete the instrument two separate times, with 2 weeks between administrations; and testing the construct validity of the instrument using structural equation modeling. We collected all measurement data using a commercially available online platform. We have summarized sample scale items, descriptive, reliability, and validity statistics of the instrument employed to measure the EMPOWER trial in Table 1.

Table 1.

Sample Scale Items, Descriptive Statistics, Reliability and Validity Statistics of the Instrument Employed to Measure the EMPOWER Trial.

		Descriptive statistics				Reliability and validity statistics
Construct	Sample scale item	Possible range	Observed range	M	SD	CR	% AVE	Pearson’s r	R ²
1. Child Physical Activity	● Yesterday, how many total minutes was your child physically active throughout the day?	0.00-500.00	0.00-400.00	101.77	80.52	—	—	0.67	0.22
● Maternal-Facilitated Environment for Child Physical Activity	● How often do you find fun ways for your child to be physically active in your home, yard, or apartment complex? ● Never–Always	3.00-15.00	5.00-15.00	12.01	2.12	0.76	52.3	0.77	—
● Maternal-Facilitated Emotional Coping for Child Physical Activity	● How sure are you that you can help your child manage any negative emotions if you encourage them to be physically active? ● Not at all sure–Completely sure	3.00-15.00	4.00-15.00	12.38	2.30	0.78	53.9	0.72	—
● Maternal-Facilitated Expectations for Child Physical Activity	● If your child participates in 2 hours of physical activity every day they will have a better weight? ● Not at all likely–Extremely likely ● Overall, how important is it to you that your child has a better weight? ● Not at all important–Extremely important	4.00-100.00	23.00-100.00	81.67	18.40	0.88	64.1	0.71	—
● Maternal-Facilitated Self-Control for Child Physical Activity	● How sure are you that you can plan to have your child be physically active for 2 hours every day? ● Not at all sure–Completely sure	3.00-15.00	5.00-15.00	12.97	2.27	0.83	63.3	0.72	—
● Maternal-Facilitated Self-Efficacy for Child Physical Activity	● How confident are you that you can get your child to be physically active for 2 hours every day? ● Not at all confident–Completely confident	3.00-15.00	6.00-15.00	12.48	2.37	0.86	66.9	0.74	—
2. Child Fruit and Vegetable Consumption	● Yesterday, how many total cups of vegetables did your child eat?	0.00-12.00	0.00-9.00	2.80	1.73	—	—	0.64	0.24
● Maternal-Facilitated Environment for Child Fruit and Vegetable Consumption	● How often do you have enough fruits and vegetables at home for your child to be able to eat five cups every day? ● Never–Always	0.00-12.00	1.00-12.00	8.43	2.47	0.82	59.8	0.71	—
● Maternal-Facilitated Emotional Coping for Child Fruit and Vegetable Consumption	● How sure are you that you can help your child manage any negative emotions from your child when you encourage him or her to eat fruits and vegetables? ● Not at all sure–Completely sure	0.00-12.00	2.00-12.00	9.29	2.43	0.86	67.9	0.67	—
● Maternal-Facilitated Expectations for Child Fruit and Vegetable Consumption	● If your child eats five cups of fruits and vegetables every day they will have a better weight? ● Not at all likely–Extremely likely ● Overall, how important is it to you that your child have a better weight? ● Not at all important–Extremely important	0.00-64.00	0.00-64.00	50.81	14.15	0.88	65.9	0.88	—
● Maternal-Facilitated Self-Control for P Child Fruit and Vegetable Consumption	● How sure are you that you can plan to have your child eat five cups of fruits and vegetables every day? ● Not at all sure–Completely sure	0.00-12.00	1.00-12.00	9.58	2.33	0.85	66.5	0.71	—
● Maternal-Facilitated Self-Efficacy for Child Fruit and Vegetable Consumption	● How confident are you that you can get your child to eat five cups of fruits and vegetables every day, even if they do not like them? ● Not at all confident–Completely confident	0.00-12.00	0.00-12.00	8.39	3.01	0.90	74.1	0.76	—
3. Child Sugar-Free Beverage Intake	● Yesterday, how many total glasses of sugar-free drinks did your child drink?	0.00-12.00	0.00-11.00	2.45	2.02	—	—	0.71	0.25
● Maternal-Facilitated Environment for Child Sugar-Free Beverage Intake	● How often do you drink sugar-free drinks at home with your child? ● Never–Always	0.00-12.00	0.00-12.00	9.43	3.04	0.86	68.0	0.76	—
● Maternal-Facilitated Emotional Coping for Child Sugar-Free Beverage Intake	● How sure are you that you can manage any negative emotions from your child if you replace sugar-sweetened drinks with sugar-free drinks? ● Not at all sure–Completely sure	0.00-12.00	0.00-12.00	9.83	2.63	0.93	81.1	0.71	—
● Maternal-Facilitated Expectations for Child Sugar-Free Beverage Intake	● If your child drinks sugar-free drinks instead of sugar-sweetened drinks they will be more relaxed? ● Not at all likely–Extremely likely ● Overall, how important is it to you that your child be more relaxed? ● Not at all important–Extremely important	0.00-64.00	2.00-64.00	48.13	15.43	0.90	69.4	0.66	—
● Maternal-Facilitated Self-Control for Child Sugar-Free Beverage Intake	● How sure are you that you can reward your child for replacing sugar-sweetened drinks with sugar-free drinks? ● Not at all sure–Completely sure	0.00-12.00	3.00-12.00	10.12	2.25	0.88	70.7	0.74	—
● Maternal-Facilitated Self-Efficacy for Child Sugar-Free Beverage Intake	● How confident are you that you can get your child to drink sugar-free drinks every day instead of sugar-sweetened drinks? ● Not at all confident–Completely confident	0.00-12.00	0.00-12.00	9.75	2.56	0.91	76.8	0.70	—
4. Child Screen Time	● Yesterday, how many minutes did your child watch TV, DVDs, or movies?	0.00-1000.00	0.00-800.00	104.65	98.61	—	—	0.72	0.14
● Maternal-Facilitated Environment for Child Screen Time	● How often do you participate in screen time at home with your child? ● Never–Always	3.00-15.00	4.00-15.00	11.52	2.15	0.79	66.4	0.72	—
● Maternal-Facilitated Emotional Coping for Child Screen Time	● How sure are you that you can help your child adjust to reducing their screen time to less than 2 hours per day? ● Not at all sure–Completely sure	3.00-15.00	4.00-15.00	12.70	2.34	0.88	71.9	0.71	—
● Maternal-Facilitated Expectations for Child Screen Time	● If your child participates in less screen they will be healthier? ● Not at all likely–Extremely likely ● Overall, how important is it to you that your child have better health? ● Not at all important–Extremely important	4.00-100.00	13.00-100.00	75.19	21.84	0.91	72.6	0.73	—
● Maternal-Facilitated Self-Control for Child Screen Time	● How sure are you that you can set goals to reduce your child’s screen time to no more than 2 hours per day ● Not at all sure–Completely sure	3.00-15.00	6.00-15.00	13.13	2.26	0.87	69.2	0.71	—
● Maternal-Facilitated Self-Efficacy for Child Screen Time	● How confident are you that you can get your child to spend no more than 2 hours per day with screen time? ● Not at all confident–Completely confident	3.00-15.00	3.00-15.00	11.51	2.91	0.81	59.6	0.72	—

Note. EMPOWER = Evaluation of Enabling Mothers to Prevent Pediatric Obesity Through Web-Based Education and Reciprocal Determinism; CR = composite reliability; AVE = average variance extracted. Data were collected from a unique sample of mothers (n = 224) prior to beginning EMPOWER trial. A total of 31 respondents from the sample completed the instrument a second time, 2 weeks following the first administration to calculate a test–retest correlation coefficient. Adapted with permission from “Impact Evaluation of Enabling Mothers to Prevent Pediatric Obesity Through Web-Based Education and Reciprocal Determinism (EMPOWER) Randomized Control Trial,” A. P. Knowlden, M. Sharma, R. R. Cottrell, B. R. A. Wilson, and M. L. Johnson, 2015, Health Education & Behavior, 42, 171-184. Copyright 2014 by Society of Public Health Education.

Ethics

We used the Consolidated Standards of Reporting Trials (CONSORT) criteria to guide our reporting of the EMPOWER trial (Rennie, 2001). We conducted data collection under the auspices of two separate IRBs. Our approval to implement the trial was granted by the University of Cincinnati IRB with a status of minimal risk to participants. We sought consent from all participants prior to enrolling them in the trial. Participants of the EMPOWER trail were offered a monetary incentive of US$55.00. Our approval to collect data at 1-year and 2-years postintervention was provided by the University of Alabama IRB. We offered participants that agreed to provide 1- and 2-year follow-up data US$5.00 for each phase of data collection.

Sample Size

EMPOWER was a one-within, one-between, mixed factorial design. Using previously published family-centered childhood obesity interventions (Warren et al., 2007), we used a power of 0.80, an alpha of .05, and an effect size of 0.20 to calculate a sample size to detect statistically significant main effects and interactions for the outcome variables of the trial. After inflating for attrition, we calculated a total required sample size of 57 (Faul, Erdfelder, Buchner, & Lang, 2009). We modeled missing data using the expectation maximization algorithm (EM; Gold & Bentler, 2000); a two-step (expectation and maximization), iterative method to impute missing means and variances from data based on observed values for a given variable. Prior to applying EM, we conducted Little’s missing completely at random (MCAR) test to the null hypothesis that data were MCAR (Little, 1988). The significance level for this hypothesis was set at .05, suggesting that rejection of the null was indicative of data missing at random (MAR). MAR data can be predicted by other observed variables, yet does not depend on any other unobserved variables; thus, permitting the use of imputation techniques.

Statistical Method

Our primary independent variable in this study was the intervention assignment: a two-level, categorical variable comprising the experimental, EMPOWER intervention, and the active control, Health Lifestyles intervention (between-subjects effect). Our second independent variable was time: a five-level, categorical variable measured at baseline (Week 0); posttest (Week 4); 1-month postintervention follow-up (Week 8); 1-year postintervention follow-up (Week 60), and 2-year postintervention follow-up (Week 112). The primary dependent variables we sought to change included four child behaviors: fruit and vegetable consumption, physical activity, sugar-sweetened beverage intake, and screen time. We analyzed main effects and interactions for child behaviors through a series of repeated-measures analysis of variance (RM ANOVA) models. To improve these four child behaviors, we also sought to change five maternal-facilitated constructs of social cognitive theory, namely, environment, emotional coping, expectations, self-control, and self-efficacy. We analyzed main effects and interactions of these five dependent variables using repeated measures multivariate analysis of variance (RM MANOVA) models.

We evaluated the within-subjects assumption of homogeneity of variance, using Mauchly’s W. If we did not meet the sphericity assumption, we used the Greenhouse-Geisser corrected F-statistic. We evaluated the between-subjects assumption of homogeneity of variance through Levene’s test. If we did not meet the assumption, we applied a more stringent p value of .01 to determine significance. We gauged the effect sizes of any significant main effects and/or interactions using Cohen’s f values of 0.1 to 0.24 to indicate a small effect, 0.25 to 0.39 to indicate a moderate effect, and 0.4 to 1.0 to indicate a large effect (Cohen, 1988). We applied a Bonferroni correction when evaluating pairwise comparisons to protect against the potential for familywise errors. For any significant group-by-time interactions, we conducted change score analyses. To build our change score models, we regressed change scores for significant child behaviors onto change scores for significant maternal-facilitated constructs.

Results

Participant Retention

During our initial enrollment period, we screened a total of 61 respondents. Four did not meet our inclusion criteria and so we excluded them from participating. Of the remaining 57 enrollees, we randomized 29 to receive the EMPOWER intervention (experimental) and 28 to receive the Health Lifestyles intervention (active control) at baseline (Week 0). We lost six participants at posttest (Week 4; 11% attrition); one additional participant at 1-month postintervention follow-up (Week 8; 12% attrition), six additional participants at 1-year postintervention follow-up (Week 60; 23% attrition), and seven additional participants at 2-year postintervention follow-up (Week 112; 35% attrition). In total, we lost 20 enrolled participants from baseline to 2-year follow-up. Ten participants were lost to follow-up from each group (total of 20) at 2-year follow-up. We illustrate the flow of participants through the EMPOWER trial in Figure 1.

Figure 1.

Flow of participants through the EMPOWER trial.

Baseline Equivalency

We conducted several layers of modeling to gauge the equivalency of the two groups at baseline. We first tested between-group differences for all continuous variables using a one-way MANOVA. Our results found no significant differences between the two groups from an omnibus perspective (F[26, 17] = 0.831, Λ_Pillai = 0.560, p = .673). Next, we modeled each continuous variable separately using a series of one-way ANOVAs. Individual tests suggested no significant differences between the two groups at baseline (p ≥ .05). We evaluated baseline differences for all categorical differences using chi-square and Fisher’s exact tests. Analysis suggested both groups were equivalent for all demographic variables at baseline. The participants of the EMPOWER trial were primarily White (70.5%), married (75.0%), unemployed/homemakers with a mean age of 35.80 years (SD = 7.48). The children of the participants were also primarily White (63.6%), male (56.8%), and had a mean age of 5.18 years (SD = 0.79). We summarize baseline demographic characterizes of the participants in Table 2.

Table 2.

Comparison of Categorical Demographic Variables Between Participants in the Experimental (n = 29) and Control (n = 28) Groups Modeled With Chi-Square Tests of Independence and Fisher’s Exact Test at Baseline.

	Groups
Variable	Treatment, f (%)	Control, f (%)	p
1. Race of Mother			.551*
African American	4 (13.8)	1 (3.6)
Asian	1 (3.4)	3 (10.7)
Caucasian	20 (69.0)	18 (64.3)
Hispanic	3 (10.3)	4 (14.3)
American Indian/Alaska Native	0 (0.0)	0 (0.0)
Native Hawaiian/Pacific	0 (0.0)	0 (0.0)
More than one race	1 (3.5)	2 (7.1)
Other	0 (0.0)	0 (0.0)
2. Marital Status of Mother			.167*
Unmarried (single, divorced, widowed)	7 (24.1)	3 (10.7)
Married	21 (72.4)	23 (82.1)
Living with a partner	0 (0.0)	2 (7.1)
Separated, living with partner	1 (3.4)	0 (0.0)
Separated, not living with partner	0 (0.0)	0 (0.0)
3. Employment Status of Mother			.334*
Unemployed/homemaker	9 (31.0)	7 (25.0)
Employed part-time	9 (31.0)	14 (50.0)
Employed full-time	11 (37.9)	7 (25.0)
4. Gender of Child^a			.916*
Male	18 (62.1)	17 (60.7)
Female	11 (37.9)	11 (39.3)
5. Race of Child			.556*
African American	4 (13.8)	1 (3.6)
Asian	1 (3.4)	2 (7.1)
Caucasian	19 (65.5)	16 (57.1)
Hispanic	3 (10.3)	3 (10.7)
American Indian/Alaska Native	0 (0.0)	0 (0.0)
Native Hawaiian/Pacific	0 (0.0)	0 (0.0)
More than one race	2 (6.9)	6 (21.5)
Other	0 (0.0)	0 (0.0)

Note. Adapted with permission from “Impact Evaluation of Enabling Mothers to Prevent Pediatric Obesity Through Web-Based Education and Reciprocal Determinism (EMPOWER) Randomized Control Trial,” A. P. Knowlden, M. Sharma, R. R. Cottrell, B. R. A. Wilson, and M. L. Johnson, 2015, Health Education & Behavior, 42, 171-184. Copyright 2014 by Society of Public Health Education.

Chi-square test applied; all other variables analyzed with Fisher’s exact test.

p ≥ .05; Significance levels for all hypotheses set a priori at p < .05.

Two-Year Evaluation

We provided full process evaluation details in a previous article (Knowlden & Sharma, 2014). We implemented intervention treatments during Weeks 1, 2, 3, 4, and 6 of the trial. We collected measurements at baseline (Week 0), posttest (Week 4), 1-month postintervention follow-up (Week 8), 1-year postintervention follow-up (Week 60), and 2-year postintervention follow-up (Week 112). Based on Little’s MCAR test (χ² = 330.650, df = 591, p > .999), we assumed data were MAR and therefore estimated missing values using EM. We summarized impact evaluation measures for the trial at each point of measurement in Table 3.

Table 3.

Summary of Comparisons for Maternal-Facilitated Social Cognitive Theory Constructs and Child Behaviors by Group and by Time for the Sample of Mothers.

	Pretest (Week 0)		Baseline comparison	Posttest (Week 4)		One-month follow-up (Week 8)		One-year follow-up (Week 60)		Two-year follow-up (Week 120)
Variable	Tx (n = 29),M ± SD	Cnt (n = 28),M ± SD	F (p)	Tx, M ± SD	Cnt, M ± SD	Tx, M ± SD	Cnt, M ± SD	Tx, M ± SD	Cnt, M ± SD	Tx, M ± SD	Cnt, M ± SD
Child PA	120.59 ± 86.78^a	83.57 ± 60.87^a	0.938 (.338*)	135.56 ± 103.90^a	130.56 ± 69.35^a	131.39 ± 97.66	114.63 ± 65.67	117.01 ± 92.50	103.44 ± 48.37	71.59 ± 49.63	134.47 ± 74.16
MF environment for child PA	11.38 ± 1.86^a	11.93 ± 1.76^a	1.741 (.194*)	12.14 ± 1.74^a	12.50 ± 1.81^a	12.40 ± 1.70^a	13.05 ± 1.61^a	12.38 ± 2.16^a	12.70 ± 1.92^a	12.79 ± 2.57^a	12.73 ± 2.34^a
MF emotional coping for child PA	12.83 ± 1.97^a	12.14 ± 2.52^a	0.396 (.532*)	13.00 ± 1.82	13.01 ± 2.09	12.83 ± 1.66^a	13.30 ± 1.85^a	13.71 ± 1.47	12.41 ± 2.79	12.14 ± 3.61	12.90 ± 2.11
MF expectations for child PA	78.24 ± 18.11^a	75.71 ± 18.66^a	0.097 (.758*)	81.11 ± 17.07^a	90.24 ± 14.89^a	78.88 ± 19.39^a	87.55 ± 16.19^a	84.28 ± 19.04^a	86.41 ± 18.79^a	70.59 ± 30.21	75.87 ± 20.82
MF self-control for child PA	12.1 ± 02.50^a	11.0 ± 02.64^a	0.852 (.361*)	13.43 ± 2.10^a	13.38 ± 1.98^a	13.43 ± 1.82^a	13.78 ± 1.64^a	13.94 ± 1.60^a	12.45 ± 1.96^a	11.38 ±4.21^a	12.48 ± 2.53^a
MF self-efficacy for child PA	13.07 ± 2.00^a	12.25 ± 2.12^a	0.471 (.496*)	12.33 ± 2.50^a	12.04 ± 2.46^a	12.53 ± 1.92^a	12.42 ± 2.22^a	13.67 ± 1.89^a	12.62 ± 2.07^a	11.51 ± 3.40^a	14.20 ± 1.38^a
Child FVC	3.83 ± 1.78^a	2.95 ± 1.58	3.700 (.061*)	5.45 ± 2.21^a	4.29 ± 1.47	5.76 ± 2.39^a	3.97 ± 1.73	5.34 ± 1.12^a	3.28 ± 1.15	5.58 ± 1.37^a	3.07 ± 1.50
MF environment for child FVC	11.66 ± 1.78^a	10.79 ± 2.28	1.392 (.256*)	13.33 ± 1.19^a	10.77 ± 1.74	14.06 ± 1.24^a	11.41 ± 1.81	12.95 ± 2.09^a	12.01 ± 1.16	12.01 ± 3.17^a	12.95 ± 2.55
MF emotional coping for child FVC	12.45 ± 2.29	11.93 ± 2.93	2.212 (.144*)	12.17 ± 2.99	12.10 ± 2.56	12.41 ± 2.38	12.79 ± 2.43	13.11 ± 2.82	12.26 ± 2.34	11.62 ± 3.47	11.95 ± 3.04
MF expectations for child FVC	79.10 ± 19.35	79.86 ± 19.91	0.500 (.484*)	80.56 ± 17.22	89.86 ± 16.70	80.97 ± 19.64	88.13 ± 13.52	83.93 ± 19.39	84.43 ± 18.55	70.74 ± 27.76	77.57 ± 19.37
MF self-control for child FVC	13.07 ± 1.79	13.25 ± 2.35	0.071 (.791*)	13.22 ± 2.47	13.37 ± 2.00	13.38 ± 2.25	13.64 ± 1.68	13.67 ± 1.31	12.79 ± 1.92	12.38 ± 3.43	13.99 ± 2.11
MF self-efficacy for child FVC	11.93 ± 2.69	11.50 ± 3.44	0.896 (.349*)	11.90 ± 3.07	11.27 ± 3.33	11.71 ± 3.34	12.07 ± 3.20	12.25 ± 2.96	11.87 ± 2.92	12.12 ± 3.47	13.46 ± 2.42
Child SFBI	3.22 ± 1.86^a	2.82 ± 1.96^a	0.606 (.441*)	4.47 ± 2.28^a	4.66 ± 2.09^a	4.33 ± 2.38^a	4.11 ± 1.87^a	3.22 ± 2.03^a	3.24 ± 2.04^a	3.81 ± 2.35	3.77 ± 2.14
MF environment for child SFBI	12.76 ± 3.28^a	13.39 ± 2.79^a	0.896 (.349*)	13.87 ± 1.56^a	13.78 ± 2.53^a	13.83 ± 2.45	13.96 ± 1.71	13.46 ± 2.58^a	12.11 ± 4.13^a	12.84 ± 3.24^a	11.47 ± 3.20
MF emotional coping for child SFBI	13.69 ± 1.93	13.43 ± 2.53	0.096 (.758*)	13.04 ± 2.24	13.58 ± 2.18	13.44 ± 2.31	14.01 ± 1.34	13.65 ± 1.75	12.63 ± 2.49	13.01 ± 3.33	14.45 ± 1.49
MF expectations for child SFBI	75.59 ± 21.79	78.75 ± 18.54	1.300 (.261*)	80.83 ± 16.55	88.90 ± 15.58	80.15 ± 22.27	84.25 ± 18.04	81.85 ± 20.94	82.73 ± 21.02	76.47 ± 26.74	81.04 ± 21.41
MF self-control for child SFBI	13.28 ± 2.00	13.07 ± 2.69	0.003 (.953*)	13.47 ± 2.09	14.18 ± 2.17	13.19 ± 2.59	14.30 ± 1.20	13.60 ± 2.18	12.94 ± 2.21	11.91 ± 3.23	13.39 ± 2.46
MF self-efficacy for child SFBI	13.52 ± 2.05	13.64 ± 2.51	0.231 (.633*)	13.26 ± 2.07	13.44 ± 2.68	13.13 ± 2.42	13.72 ± 1.47	13.79 ± 1.66	13.57 ± 2.04	12.53 ± 3.88	14.01 ± 1.90
Child ST	122.07 ± 78.47^a	100.18 ± 58.30^a	1.197 (.280*)	82.27 ± 50.28^a	83.02 ± 46.47^a	79.58 ± 55.32^a	69.00 ± 40.05^a	77.85 ± 41.87^a	62.83 ± 31.80^a	92.78 ± 49.51	111.80 ± 61.27
MF environment for child ST	68.48 ± 21.72^a	78.46 ± 20.77^a	1.270 (.266*)	73.23 ± 19.91^a	85.22 ± 18.02^a	77.34 ± 21.16^a	77.36 ± 22.24^a	81.12 ± 18.83^a	83.49 ± 18.79^a	69.23 ± 26.17^a	79.17 ± 20.56^a
MF emotional coping for child ST	12.55 ± 2.21	12.79 ± 2.38	0.392 (.535*)	12.78 ± 2.06^a	13.04 ± 2.20^a	13.01 ± 1.99^a	13.76 ± 1.60^a	13.05 ± 2.18	12.35 ± 2.51	12.01 ± 2.18^a	11.58 ± 1.72^a
MF expectations for child ST	68.48 ± 21.72^a	78.46 ± 20.77^a	4.080 (.050*)	73.23 ± 19.91^a	85.22 ± 18.02^a	77.34 ± 21.16	77.36 ± 22.24	81.12 ± 18.83^a	83.49 ± 18.79^a	69.23 ± 26.17	79.17 ± 20.56
MF self-control for child ST	11.38 ± 2.98^a	12.11 ± 3.11^a	1.064 (.380*)	13.06 ± 1.96^a	13.24 ± 2.38^a	13.82 ± 1.67^a	13.73 ± 2.00^a	12.16 ± 2.54^a	11.62 ± 3.42^a	12.45 ± 2.57^a	11.66 ± 2.87^a
MF self-efficacy for child ST	13.48 ± 1.68^a	13.61 ± 1.99^a	0.161 (.690*)	11.46 ± 3.04^a	12.26 ± 2.69^a	11.56 ± 2.66^a	12.39 ± 2.10^a	12.96 ± 1.90^a	12.82 ± 2.04^a	11.41 ± 2.66^a	13.85 ± 2.36^a

Note. MF = maternal-facilitated; PA = minutes of physical activity; FVC = cups of fruit and vegetable consumed; SFBC = eight-ounce glasses of sugar-free beverages consumed; ST = minutes of screen time; Tx = treatment group; Cnt = control group. Missing values estimated using expectation maximization algorithm. Significance levels for all hypotheses set a priori at p < .050.

Significant pairwise comparisons (significance determined using a Bonferroni correction to correct for familywise error rate).

P value ≥.050 for baseline comparisons.

Child Behaviors

We found a significant group-by-time interaction of small effect size for child fruit and vegetable consumption (p = .033; Cohen’s f = 0.139). Our time pairwise comparisons found significant increases of 1.487 cups (95% CI [0.885, 2.089]) from pretest to posttest (p < .001); 1.481 cups (95% CI [0.813, 2.148]) from pretest to 1-month postintervention follow-up (p < .001); 0.924 cups (95% CI [0.154, 1.695]) from pretest to 1-year postintervention follow-up (p = .009); and 0.934 cups (95% CI [0.047, 1.821]) from pretest to 2-year postintervention follow-up (p = 0.032). Our group pairwise comparison suggested an overall significant increase of 1.680 daily cups of fruits and vegetables (95% CI [1.113, 2.248]) consumed by the children in the experimental group, relative to the control group (p < .001). We illustrated a profile plot of estimated marginal means illustrating group-by-time interaction for child fruit and vegetable consumption in Figure 2.

Figure 2.

Profile plot of estimated marginal means illustrating group-by-time interaction for child fruit and vegetable consumption.

We found a significant main effect of small effect size for child physical activity (p = .024; Cohen’s f = 0.124). Our time pairwise comparisons indicated a significant increase in child physical activity of 30.981 minutes (95% CI [3.862, 58.101]) from pretest to posttest (p = .015). Our group pairwise comparisons suggested physical activity increased in the experimental group by 13.028 minutes (95% CI [12.600, 38.657]); however, the increase was not statistically significant at the group level (p = .313). We detected a significant main effect of moderate effect size for child sugar-free beverage intake (p < .001; Cohen’s f = 0.321), suggesting both groups improved in this behavior over time. Our time pairwise comparisons indicated significant increases in child sugar-free beverage intake of 1.545 cups (95% CI [0.785, 2.305]) from pretest to posttest (p < .001); 1.198 cups (95% CI [0.305, 2.092]) from pretest to 1-month, postintervention follow-up (p = .002); and 1.340 cups (95% CI [0.196, 2.483]) from posttest to 1-year postintervention follow-up (p = .012). Our group pairwise comparisons suggested total sugar-free beverage intake increased in the experimental group by 0.093 cups (95% CI [−0.545, 0.731]); however, the increase was not statistically significant at the group level (p = .772).

We found a significant main effect of moderate effect size for child screen time, indicating both groups improved in this behavior (p < .001; Cohen’s f = 0.303). Our time pairwise comparisons indicated significant decreases in child screen time behavior of 28.476 minutes (95% CI [5.845, 51.107]) from pretest to posttest (p = .005); 36.831 minutes (95% CI [8.287, 65.376]) from pretest to 1-month, postintervention follow-up (p = .004); 40.786 (95% CI [10.075, 71.496]) from pretest to 1-year postintervention follow-up (p = .033); and 31.952 minutes (95% CI [6.737, 57.167]) from 1-year postintervention follow-up to 2-years postintervention follow-up (p = .005). Our group pairwise comparisons suggested total child screen time decreased in the active control group by 5.545 minutes (95% CI [−10.933, 22.022]); however, the decrease was not statistically significant at the group level (p = .503).

Maternal-Facilitated Social Cognitive Theory Constructs

We found a significant group-by-time interaction of small effect size for the maternal-facilitated child fruit and vegetable consumption environment construct (p < .001; Cohen’s f = 0.289). Our time pairwise comparisons found significant increases in the environment construct of 0.825 units (95% CI [0.220, 1.431]) from pretest to posttest (p = 0.008); 1.518 units (95% CI [0.995, 2.040] from pretest to 1-month postintervention follow-up (p < .001); 1.263 units (95% CI [0.555, 1.970]) from pretest to 1-year postintervention follow-up (p = .001); 1.206 units (95% CI [0.379, 2.140]) from pretest to 2-year postintervention follow-up (p = .001); and 0.692 units (95% CI [0.333, 1.051]) from posttest to 1-month postintervention follow-up (p < .001). Our group pairwise comparison suggested an overall significant increase in the environment construct of 1.214 units (95% CI [0.685, 1.743]) in the experimental group, relative to the control group (p < .001). We did not identify any other significant effects for the remaining maternal-facilitated child fruit and vegetable consumption constructs (p ≥ .05). We conducted a change score analysis for the significant group-by-time interactions we detected for child fruit and vegetable consumption as well as the maternal-facilitated child fruit and vegetable consumption environment construct. Our analysis suggested the maternal-facilitated environment construct accounted for 32.8% of the variance in child fruit and vegetable consumption from pretest to 1-month postintervention follow-up (p < .001). All other points of measurement were not significant (p ≥ .05).

In terms of the maternal-facilitated child physical activity constructs, we found a significant time effect for the constructs of environment (p = .024), expectations (p = .005), self-control (p < .001), and self-efficacy (p < .001). We also found significant time effects for the maternal-facilitated child sugar-free beverage construct of environment (p = .009). In terms of the maternal-facilitated screen time constructs, we found a significant time effect for the environment (p < .001), emotional coping (p = .014), self-control (p < .001), and self-efficacy constructs (p = .001); however, none of these constructs were significant at the group level (p ≥ .05). We provided details of the significant time pairwise comparisons for the maternal-mediated social cognitive theory constructs in Table 3.

Discussion

Our present study applied a longitudinal design to determine whether there were statistically significant main effects and/or interactions for four child behaviors (fruits and vegetables, physical activity, sugar-free beverage consumption, screen time) and five social cognitive theory maternal-facilitated constructs (environment, emotional coping, expectations, self-control, self-efficacy), between two intervention groups (EMPOWER/Healthy Lifestyles) at 2-year postintervention follow-up. The most important finding from our study suggested a maternal-focused approach led to an overall increase of 1.680 daily cups of fruits and vegetables in the experimental EMPOWER group, relative to the active control, Healthy Lifestyles, group at the 2-year postintervention follow-up mark. Other studies have also found that family-and-home-based childhood obesity interventions can improve dietary and physical activity behaviors (French, Gerlach, Mitchell, Hannan, & Welsh, 2011; Gentile et al., 2009; Patrick et al., 2006), though it remains unclear if changes in such intermediate variables leads to improvements in weight-related outcomes (Showell et al., 2013). We summarized the most important findings from our study in Table 4.

Table 4.

Summary of Repeated Measures Models at 2-Year Postintervention Follow-Up Maternal-Facilitated Social Cognitive Theory Constructs and Child Behaviors.

Variable	p
Child physical activity	.048^a
Maternal-facilitated environment for child physical activity	.024^a
Maternal-facilitated emotional coping for child physical activity	.325^c
Maternal-facilitated expectations for child physical activity	.005^a
Maternal-facilitated self-control for child physical activity	<.001^a
Maternal-facilitated self-efficacy for child physical activity	<.001^a
Child fruit and vegetable consumption	.033^b
Maternal-facilitated environment for child fruit and vegetable consumption	<.001^b
Maternal-facilitated emotional coping for child fruit and vegetable consumption	.611^c
Maternal-facilitated expectations for child fruit and vegetable consumption	.569^c
Maternal-facilitated self-control for child fruit and vegetable consumption	.070^c
Maternal-facilitated self-efficacy for child fruit and vegetable consumption	.316^c
Child sugar-free beverage consumption	<.001^a
Maternal-facilitated environment for child sugar-free beverage intake	.009^a
Maternal-facilitated emotional coping for child sugar-free beverage intake	.478^c
Maternal-facilitated expectations for child sugar-free beverage intake	.271^c
Maternal-facilitated self-control for child sugar-free beverage intake	.062^c
Maternal-facilitated self-efficacy for child sugar-free beverage intake	.844^c
Child screen time	<.001^a
Maternal-facilitated environment for child screen time	<.001^a
Maternal-facilitated emotional coping for child screen time	.014^a
Maternal-facilitated expectations for child screen time	.160^c
Maternal-facilitated self-control for child screen time	<.001^a
Maternal-facilitated self-efficacy for child screen time	.001^a

Note. Missing values estimated using expectation maximization algorithm. Significance levels for all hypotheses set a priori at p < .050.

Significant p value for main effect over time (<.05). ^bSignificant p value for group × time interaction (<.05). ^cp value ≥.05 for main effect.

An advantage of the EMPOWER trial was the direct measurement of social cognitive theory constructs, which allowed us to explicitly determine which constructs likely lead to the behavior change (Knowlden & Sharma, 2015). Our change score analysis suggested the maternal-facilitated environment construct explained nearly one third of the increase in child fruit and vegetable consumption, suggesting family-and-home-based interventions that actualize social cognitive theory can induce beneficial changes in child dietary patterns. In this regard, EMPOWER sought to change both social (maternal role modeling of fruit and vegetable consumption in front of, and with, their child) and physical (increased child access and availability to fruits and vegetables) attributes of the home environment. Subsequently, we recommend that interventionists seeking to change child fruit and vegetable behavior focus on both physical and social characteristics of the home milieu.

It is important to note that while we did not detect significant between-group differences for physical activity, sugar-free beverage intake, or screen time, we did detect within-group differences for these behaviors. These main effects were either no longer present (physical activity, sugar-free beverage intake) or significantly declined (screen time) by the 2-year mark. Given both groups self-reported moderate to high levels of expectations, emotional coping, self-control, and self-efficacy for all four behaviors at baseline, our findings may suggest that if adequate behavioral capacities are present, knowledge-based programs may be sufficient to induce an intervention effect, leading to temporary behavior change. As we did not include a nontreatment control group in the EMPOWER trial it is impossible to empirically test this hypothesis.

Web-based programs may offer advantages for parent-focused programs. From the parent perspective, web-based interventions can allow participants to complete intervention activities when it is most convenient for them (Moyer & Finney, 2004) as opposed to being locked into specific dates and times. From a practitioner perspective, web-based interventions can potentially decrease intervention costs (Bewick et al., 2008).

An additional advantage of the EMPOWER trial was the long-term follow-up with participants. While other researchers have tested the efficacy of online, family-and-home-based, childhood obesity interventions (Cullen, Thompson, & Chen, 2016; Schwinn, Schinke, Fang, & Kandasamy, 2014; Wilson, Alia, Kitzman-Ulrich, & Resnicow, 2014), to the best of our knowledge, ours is the only trial that has collected data beyond 12 months from baseline. Treatment effects from obesity treatment programs can begin to degrade at 12 months postintervention (Oude Luttikhuis et al., 2009). Therefore, intervention evaluation beyond the 1-year point is an important benchmark for determining if treatment effects linked to an intervention are sustainable once the intervention has concluded (Stice, Shaw, & Marti, 2006).

Limitations

There are several limitations of the EMPOWER trial that should be considered when interpreting the findings of our study. From a design perspective, EMPOWER was a brief trial, with a dosage rate of 2.5 hours per intervention, spread across five sessions. An earlier review found the mean dosage rate for family-and-home-based childhood obesity interventions was between 8 and 20 hours (Knowlden & Sharma, 2012a). A significant proportion of variation in child fruit and vegetable consumption could not be explained by changes to the home environment. There are several possible explanations for this unexplained variance including measurement error, self-report biases, and/or failure to measure the impact of other environmental factors—such as schools or childcare centers—on the behaviors targeted by this trial.

Because of the length of the measurement instrument and limited funding, we did not collect body mass index, educational level, or income data, which may have also contributed to the unexplained variance in child fruit and vegetable consumption. As we sought parsimony for the instrument used to evaluate this intervention, we operationalized the home environment for accessibility and availability of fruits and vegetables through three items. However, given the apparent importance of the home environment, we recommend future home-based interventions seek to increase the number of items representing this construct (Spurrier, Magarey, Golley, Curnow, & Sawyer, 2008). In the current study, the instrument measuring maternal-facilitated environment for the child fruit and vegetable consumption construct combined dimensions of the physical and social environment into one construct (Hearn et al., 1998). Future research in this area should consider separating these components to evaluate the individual influences of these two, likely separate, dimensions of the home environment. The mediating influence of the mother’s behaviors on their children could be further understood by collecting mothers’ self-reported fruit and vegetable intake (Goldman, Radnitz, & McGrath, 2012).

EMPOWER only targeted mothers as the agents of change (parent-only intervention). Including both parents and children (parent plus child; family-based treatment) is currently considered the gold standard for treatment of childhood obesity (Boutelle et al., 2015). Future interventions should attempt to include as many family members as feasibly possible, including fathers, siblings, and extended family members (e.g., grandparents, aunts, uncles). An additional design limitation was the controlled nature of the intervention. We incorporated a randomized control design to assess the efficacy of the EMPOWER intervention; however, we did not test the intervention for effectiveness under real-world conditions. Furthermore, although we applied random assignment of the participants to the two arms of the intervention, we did not randomly sample participants from the population. As such, the findings of this study may not be generalizable. Finally, we experienced a significant loss to follow-up at the 2-year mark. We attempted to overcome this limitation by modeling the missing data; however, such methods are not without criticism (Dong & Peng, 2013).

Implications for Practice

The strength of the evidence for the efficacy of the parent-only approach is limited (Loveman et al., 2015; Showell et al., 2013); however, our results found that mothers are important change agents for long-term modification of behaviors hypothesized to prevent and treat childhood obesity (Golan & Crow, 2004). Subsequently, we recommend practitioners seeking to change behaviors connected to childhood obesity consider using web-based interventions, with a focus on mothers as primary agents of change. It should be noted more researchers are calling for a focus on father-based childhood obesity interventions (Freeman et al., 2012; Morgan et al., 2011). Our results suggest that practitioners can use online interventions to initiate temporary improvements in child physical activity, sugar-free beverage consumption, and screen time, provided the skills to change these behaviors are present in mothers at baseline. Practitioners could use booster sessions in an attempt to maintain changes to child behaviors (Kalarchian et al., 2009). The behavior that demonstrated the most sustained improvement was child fruit and vegetable consumption. In this context, the EMPOWER intervention provided the greatest impact on child fruit and vegetable consumption; therefore, we recommend practitioners primarily focus on child fruit and vegetable behavior, with a particular emphasis on using social cognitive theory to improve the maternal-facilitated home environment.

Footnotes

Authors’ Note

Portions of this article were presented at the 2015 American Public Health Association Annual National Convention.

Declaration of Conflicting Interests

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Funding

The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The intervention study was supported by a University of Cincinnati Graduate School Distinguished Dissertation Completion Fellowship.

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