Abstract
Objective:
The percentage of obese children in the United States has increased dramatically over the past three decades, particularly among ethnic/ racial minorities. This study sought to examine the impact of a clinical case-management intervention based upon the Transtheoretical Model (TTM) to reduce obesity and increase physical activity in children.
Methods:
Nineteen obese African-American children ages 8-12 were recruited from two pediatric clinics and were randomized to either a 12-week intervention group or a control group. Dependent variables included body mass index (BMI) percentile, physical activity, and stage of change for the child and parent.
Results:
In comparison to the control group, the intervention group demonstrated significant decreases in BMI and improvements in daily vigorous physical activity. The children in the intervention group demonstrated movement toward action/maintenance stages of change.
Conclusions:
A 12-week TTM-based case management intervention can have a favorable impact on obesity and physical activity in African-American child.
Introduction
The percentage of obese children in the United States ages 6-11 has increased from 5% in 1970 to 18.8% in 2004. 1 Obesity is an emerging problem among children, particularly among ethnic and racial minorities. A number of interventions have been conducted to reduce obesity and/or increase physical activity (PA) in childhood, with little indication of a consistent positive effect on either. 2
The Transtheoretical Model (TTM) has been successfully used to treat many behavior-linked health problems. 3 The TTM promotes change through an effective-cognitive-behavioral approach that is tailored to the patient’s stage of change. The stages include precontemplation (no plan to change behavior), contemplation (plans to change soon), preparation (change is imminent), action (actively engaged in change), and maintenance (relapse prevention). Once the stage has been assessed, treatment can be individually tailored. The addition of case management to the TTM has proven to be efficacious in successfully managing asthma 4 and type 1 diabetes in children 5 when using a family-focused approach.
The objective of the current study was to test the feasibility and efficacy of a case management intervention using TTM to reduce obesity and related risk factors in African American (AA) children.
Methods
Nineteen obese (BMI ≥ 95th percentile for age and sex) AA children ages 8-12 years were recruited during office visits at 2 urban pediatric clinics. This study was approved by the Institutional Review Board at the University of Louisville, and informed consent/assent was obtained for all participants. Demographic data, habitual PA, stage of change for weight loss, and height/weight were collected, followed by randomization to either the control or case management (CM) group. Body mass index (BMI) percentile was calculated using the 2000 Centers for Disease Control and Prevention Growth Charts to allow for comparison across ages. Physical activity was measured using Actical™ activity monitors (Respironics, Mini-Mitter, Bend, OR, USA) continuously for 7 days using a previously validated protocol. 6 Stage of change for the parent and child was assessed using 2 modified versions of the University of Rhode Island Change Assessment (URICA). 7
The control group received usual care, whereas families assigned to the CM group met with the case manager in their home 7 days later. Data were collected at baseline and at posttest following the 12-week intervention. Most children (n = 14) had fasting lipid panels, insulin, and glucose assessed as part of their routine clinical evaluations prior to intervention, and these data are presented in Table 1.
Laboratory Values of Subsample with Clinical Measures
Abbreviations: CM, case management; HDL, high-density lipoprotein; LDL, low-density lipoprotein.
Note: One extreme outlier was removed from the Control group for elevated insulin, and one extreme outlier was removed from CM group for elevated G/I ratio.
A case management planning group supervised the CM intervention, which included dietary change and increasing PA for the child. Depending on the stage of change for the parent and child, an intervention was designed that was either cognitive or behavioral in nature. Cognitive interventions were selected for families in the precontemplation and contemplation stages, whereas behavioral interventions were used for those in the action or maintenance stages. 3 The case manager delivered the module during a weekly phone call and assisted the parent and child in identifying barriers to completing the activity, and then modified the activity or selected a new activity to be performed during the subsequent week. After each 4-week period, the case manager met with the family, collected all of the weekly compliance records, and administered the modified URICA to both the parent and child. Based on the results of the assessment, the next 4-week intervention was designed.
Results
Each individual’s stage of change scores were ranked 1-4, and difference scores were calculated for the child and parent. Separate logistic regression equations were constructed, with the treatment group as the independent variable (IV) and the difference scores as the dependent variable (DV). The overall model for the children was significant (χ2 = 5.81,
To assess changes in body composition and PA, a series of analyses of variance was run with treatment group as the IV and change in BMI percentile or PA as the DV. Body mass index percentile changes were significantly different (F = 7.56,
Demographics, Physical Activity, and Stage of Change Scores
Abbreviations: BMI, body mass index; MET, metabolic equivalent; PA, physical activity; SD, standard deviation.
Note: Data presented are mean ± SD.
Conclusions
Children in the CM group exhibited significant positive movement along the stage of change continuum, increased time in vigorous PA, and reduction in BMI percentile. Higher scores in the action stage of change predicted more time spent in vigorous PA as a result of the child’s stage of change significantly progressing, independent of the parent’s stage. This independence might reflect the relative autonomy of vigorous PA compared to an overall increase in PA, which might require greater logistic support from parents. 8 A 1-cm difference in height was observed between the intervention and control groups, indicating a nonsignificant difference in growth. Although the cause of this difference is unknown, it might be speculated to be attributable to changes in diet in response to the intervention. Research from Albala and colleagues 9 suggests that replacement of sugar-sweetened beverages with milk might have a positive effect on growth in children. Unfortunately, although the case management intervention modules did address nutrition in the current study, we did not assess diet with sufficient rigor to explore this possibility in the current study.
Although the current results are promising, the limited sample size of the present investigation prohibited more sophisticated analyses that could elucidate the impetus for the changes. For example, it would be valuable to perform a mediation analysis to determine if the changes in BMI are explained by changes in PA or if the movement in stage of change might influence BMI through other behaviors such as changes in diet. These potential mediators should be examined in future studies. Furthermore, it is important that future research include qualitative data collection to ascertain information about the acceptability of the intervention for the families. Although the lack of dropouts in the present investigation would suggest that the intervention was tolerable to the participants, qualitative data would provide information that could be used to tailor the intervention to potentially increase effectiveness or maintain the present level of retention.
Several limitations may have affected the findings, including the short, 12-week duration. It is very promising that children progressed out of the precontemplation stage, indicating that the intervention heightened their awareness of their weight problem, resulting in decreased BMI percentile over a short time period. Additionally, the study used a large team of professionals for the case management planning group; such a large team might not be available and/or feasible in a representative pediatric clinic. However, the strategies employed in the current study can certainly be used by case managers in other primary care clinics. Furthermore, the case management approach is cost effective and comparable to similar clinic-based interventions. For example, Goldfield et al reported a cost of $1390 per family for a 13-session, individually based behavioral weight loss program with similar efficacy. 10 Using the same methodology to calculate cost per participant, the current case management approach cost approximately $600 per individual treated. The difference in cost per patient was primarily owing to the employment of a health educator to deliver the intervention in the current study compared to a licensed counselor employed by Goldfield and colleagues. Finally, because our control group was “standard care,” it is unclear whether the changes observed in the CM group are owing to the intervention itself or to simply having a case manager who is actively involved with the family.
To our knowledge, this is the first study to demonstrate effectiveness of a case management approach using TTM in treating pediatric obesity in a clinical setting. Our current results were better than those reported in a recently published study using TTM in an after-school setting, potentially because of less parental engagement in the after-school study. 11 This 12-week pilot study to assess the effectiveness of a TTM-based case management intervention provided preliminary evidence that individually tailored interventions may be effective in managing obesity in AA children.
Footnotes
Acknowledgements
The authors wish to thank Wendy Bibeau, Myra Goldman, Monique M. Howard, Mirzada Kurbasic, Ximena L. Valdes, Rita Thomas Wedig, and V. Faye Jones for their assistance with the identification and case management of the intervention subjects. We also thank Mindy Staley and Paul Caudill for their assistance with data collection and data entry. Finally, we express our appreciation to the families for their ongoing participation during the 12-week protocol.
This study was supported by a University of Louisville School of Medicine Grant-in-Aid.