Developing and testing an instrument to evaluate childhood obesity prevention behaviors based on social cognitive theory

Manoj Sharma, MBBS, CHES, Ph.D.Associate Professor, University of Cincinnati

Donald I. Wagner, HSDProfessor, University of Cincinnati

Session 4190, Board 1, November 7 (T), 2:30 pm

Background

Since 1980 the prevalence of overweight has doubled for children and tripled for adolescents

The national health care expenditures related to overweight and obesity in adults are estimated between $98 billion to $129 billion

In the Healthy People 2010 Report, the goal for reducing overweight and obesity in children and adolescents is aimed at 5 percent from the 1988-94 baseline of 11 percent

Problems with Childhood Obesity

The Bogalusa Heart Study found that by age 10 years, 60% of overweight children have at least one biochemical or clinical cardiovascular risk factor and 25% have more than two

Childhood obesity is associated with several short term medical consequences such as adverse blood lipid profile, altered glucose metabolism, obstructive sleep apnea and long term effects such as higher risk of hypertension, diabetes, cardiovascular disease, gall bladder disease, and osteoarthritis in adulthood

Public health strategies to combat childhood obesity

Promoting breastfeedingLimiting television viewingEncouraging physical activityIncreasing fruit and vegetable intakeControlling portion sizeLimiting soft drink consumption

Purposes of this study

The purpose of this study was to develop and test an instrument that reified the constructs of expectations, self-efficacy and self control for four common behaviors modulated in childhood obesity prevention programs, namely: television viewing physical activity fruit/vegetable intake water consumption.

Secondarily, to examine the extent to which selected social cognitive theory constructs (expectations, self-efficacy, and self control) can predict the four behaviors of: Daily moderately intense physical activity of 30 minutes Limiting television viewing to two hours per day Increasing water consumption to eight glasses per day Increasing fruit and vegetable intake to five or more servings

per day in upper elementary children.

Methodology

Design: Cross-sectionalStudy conducted in December 2004 Institutional Review Board (IRB)

permission from the University was obtained

Parental permission was obtained Child’s assent obtained before filling

the questionnaire

Instrumentation

A 52-item scale was developed and validated for face and content validity by a panel of six experts in a two round process

Administered to 159 fifth graders Confirmatory factor analysis confirmed one

factor solution for each of the components measuring outcome expectations, outcome expectancies and self-efficacy for each of the four behaviors

Cronbach’s alpha and test-retest reliability coefficients for all the subscales were found to be over 0.70

Demographics of the sample

Age: 69.9% - 10 yr olds 27.9% - 11 yr olds 2.2% - 12 yr olds

Gender: 47% - boys 53% - girls

Ethnicity: 64.7% - Caucasian 22.8% - African American 2.2% - American Indian 7.4% - Other race

Previous exposure

Exposure to sessions about healthy eating in school : 68.4% - 3 or more 19.1% - 2 5.9% - 1 5.9% - None

Exposure to sessions about engaging in physical activity or exercise at home: 69.9% - 3 or more 14.0% - 2 9.6% - 1 5.9% - None

Means and standard deviations of behavioral variables

n Minimum

Maximum Mean Std. Deviatio

n

Number of minutes exercised at home in past 24 hours

134 0 240 29.99 42.09

Number of hours watched TV in past 24 hours

135 0 10 2.51 2.36

Number of glasses of water consumed in past 24 hours

133 0 15 3.59 2.78

Number of servings of fruits ate in past 24 hours

132 0 6 1.87 1.51

Number of servings of vegetables ate in past 24 hours

132 0 6 1.81 1.55

Number of fruits and vegetables consumed in the past 24 hours

131 0 11 3.67 2.61

Means and standard deviations of SCT variables for exercise

n Minimum Maximum Mean Std. Deviatio

n

Expectations for exercising 30 min daily

127 0 60 30.46 15.07

Self-efficacy for

exercising 30 min daily 132 0 12 6.72 3.48

Self control to set goals for exercising 30 min. daily

135 0 4 2.66 1.34

Means and standard deviations of SCT variables for TV watching

n Minimum Maximum Mean Std. Deviatio

n

Expectations for watching less than 2

hours of TV daily

125 0 64 24.98 16.69

Self-efficacy for watching less than 2 hours of TV daily

129 0 12 5.93 3.76

Self-control for restricting TV watching to less

than 2 hours daily

134 0 4 2.16 1.57

Means & standard deviations of SCT variables for drinking water

n Minimum Maximum Mean Std. Deviatio

n

Expectations for drinking 8 or more glasses of water per day

130 0 64 34.20 15.78

Self-efficacy for drinking 8 glasses of water per day

130 0 12 7.05 3.51

Self control for drinking 8 glasses of water per day

134 0 4 2.57 1.44

Means & standard deviations of SCT variables for fruits/veg.

n Minimum Maximum Mean Std. Deviatio

n

Expectations for eating five or more servings of fruits and vegetables daily

133 0 64 36.18 17.18

Self-efficacy for eating five or more servings of fruits and vegetables daily

134 0 12 6.71 3.59

Self control for eating five or more servings of fruits & vegetables daily

132 0 4 2.56 1.45

Final regression model for exercising (adjusted R2 0.072)

Unstandardized Coefficients B

Std.

Error Standardized Coefficients Beta

t p-value

(Constant) -11.706 13.721

-.853

Number of times taught in school to do physical activity/exercise at home

10.033 4.431 .205 2.264 .026

Self-efficacy for exercising 30 min daily at home

2.532 1.122 .205 2.256 .026

Final regression model for TV watching (adjusted R2 0.055 )

Unstandardized Coefficients B

Std.

Error Standardized Coefficients Beta

t p-value

(Constant) 4.819 .830 5.809

Number of times taught in school about healthy eating

-.610 .279 -.201 -2.190 .031

Self-control through goal setting for restricting TV watching to less than 2 hours per day

-.301 .146 -.189 -2.062 .042

Final regression model for water drinking (adj. R2 0.091)

Unstandardized Coefficients B

Std.

Error Standardized Coefficients Beta

t p-value

(Constant) 1.576 .605 2.606

Expectations for drinking 8 or more glasses of water per day

5.608E-02 .016 .315 3.528 .001

Final regression model for fruits/veg. (adj. R2 0.137)

Unstandardized Coefficients B

Std.

Error Standardized Coefficients Beta

t p-value

(Constant) 1.747 .479 3.647

Self-efficacy for eating five or more servings of fruits and vegetables daily

.275 .062 .380 4.420 .000

Main conclusions

In the case of physical activity, the number of sessions of physical education (p<0.026) and self-efficacy for exercising (p<0.026) were significant predictors

In the case of watching TV, the number of times taught about healthy nutrition (p<0.03) and self control for watching less than two hours of TV (p<0.04) were significant predictors.

Main conclusions…2

In the case of drinking water, the only significant predictor was expectations for drinking eight or more glasses of water (p<0.001).

In the case of fruit and vegetable consumption, the only significant predictor was self-efficacy to eat five or more servings of fruits and vegetables (p<0.0001).

Implications for Practice

More health education programs in upper elementary children are needed that promote: Daily moderate intensity physical activity of 30 minutes Limit television viewing to two hours per day Increase water consumption to eight glasses per day Increase fruit and vegetable intake to five or more

servings per day Social cognitive theory (SCT) - excellent

framework to design such interventions SCT interventions can be implemented by health

and physical education teachers

Implications for Practice…2

Self-efficacy can be built through using credible role models. Boosted by focusing on specific tasks, breaking down

complex tasks into simple steps, inculcating participatory practice that leads to mastery

To influence self control, students must be encouraged to set goals to accomplish desired behaviors and reward themselves upon accomplishing the goal.

More needs to be done with regard to understand behavioral determinants of childhood obesity and designing and evaluating behavior change interventions

Limitations

The study did not use random selection of subjects which introduced sampling bias

One-day recall was employed to measure the primary dependent variables. While it offers advantage in accuracy of recall it may not accurately depict the typical day for the participant

The instrument was all self-report and that too introduces measurement bias. However, the instrument was read to the participants to account for varying levels of readability and reduce measurement bias.

The design of this study was cross-sectional and as such nothing can be said about temporality of association