EFFECT OF A TELEPHONE-BASED INTERVENTION ON PHYSICAL ACTIVITY AND COMPONENTS OF THE METABOLIC SYNDROME IN ADOLESCENTS

Abstract

The purpose of this study was to determine the effects of a two month telephone-based intervention in obese adolescents (BMI percentile [greater than or equal to] 95th percentile) on physical activity habits and motivation to be physically active. A secondary purpose was to assess the effects of the telephone-based intervention on individual components of the metabolic syndrome (i.e., blood pressure, waist circumference, and HDL-cholesterol). The final purpose of the study was to determine clinic follow-up rates of the participants after the intervention. Participants (n=29) were recruited at their initial visit to a medical clinic focusing on pediatric obesity and were randomly placed into a control (n=13) or intervention (n=16) group. Measurements taken included resting blood pressure and heart rate, height, weight, and waist circumference. Blood draws were obtained to measure total cholesterol, HDL-cholesterol and quantify non-HDL-cholesterol. Questionnaires completed included the Youth Risk Behavior Survey, Behavior Regulation of Exercise Questionnaire-2, a physical activity barriers questionnaire, and a demographic survey. The measurements and questionnaires were completed pre and post intervention. All participants received a New Lifestyles NL-800 pedometer and pedometer log to measure their physical activity for one week pre and post intervention. The participants in the intervention group received weekly newsletters and phone calls on various physical activity topics for seven weeks. During the seven week period, the control participants received no contact except for two phone calls to obtain baseline pedometer data and to remind participant of follow-up appointment. A series of 2x2 (group by time) repeated measures ANOVA adjusting for length of time between visits were performed to examine the effect of the intervention on physical activity levels and specific components of the metabolic syndrome. Pedometer steps did not have significant main or interaction effects and effect sizes were small (ES= -0.03 for controls and ES=0.07 for intervention). A trend for significant time and group interaction effect (p=0.06) was seen for BMI z-score where the control group decreased their BMI z-score (ES= -0.96) and the intervention group increased their BMI z-score (ES= 0.43). Waist circumference showed no significant main and interaction effects (p>0.05). No main or interaction effects for systolic blood pressure. Diastolic blood pressure had a significant group effect (p<0.05), where the diastolic blood pressure was lower among those in the intervention group compared to controls. Significant main or interaction effects were not reported for HDL-cholesterol. Overall, the follow-up rate was 45% (control = 69%, intervention = 36%). In summary, a telephone-based physical activity intervention did not improve either physical activity levels or components of the metabolic syndrome. The intervention did not improve clinic follow-up rates. These results suggest that modifications need to be made to the current study in order to see the desired results. Changes may include a longer duration, a more accurate method of reporting data such as an accelerometer, or changes in the clinic to encourage a higher follow-up rate.