Applicability of the transtheoretical model in weight management in an adolescent population in Taiwan

Westernized dietary preferences and life-styles are thought to have a significant impact on the increasing prevalence of obesity in Asian populations. The increased numbers of overweight and obese adolescents is becoming an emerging health issue in Asia. Meanwhile, previous studies have indicated that adolescents\u27 self-perceived weight is poorly related to the medical definition of overweight, and considerable numbers of clinically normal-weight persons are trying to or wish to control weight. Due to the considerable prevalence of desire for weight control among adolescents who are not overweight/obese, it is important for researchers to took at the issue of weight management in non-clinical populations. The main goal of the investigation was to examine the applicability of the concepts of decisional balance and self-efficacy in weight management behavior in an adolescent population in Taiwan. The first step was to develop and evaluate a 14-item Chinese version of Decisional Balance Inventory, and a 15-item Weight Efficacy Questionnaire using a sample of 491 adolescents in a high school in Taiwan. Using split-half, cross validation procedures, a two-factor decisional balance model fit the data best (CFI=.971, RMSEA=.042) with good internal consistency for both Pros (.85) and Cons (72). Using split-half cross-validation procedures, a hierarchical four-factor self-efficacy model fit the data well (CFI=.940, RMSEA=.059) with adequate internal consistency for all scales: negative emotion (.80), availability and positive activities (.80), social pressure (.68), and physical discomfort (.80). External validity of the scales was assessed with MANOVA, ANOVAs, and follow-up Tukey tests examining the relationships between decisional balance and Stage, and the relationships between self-efficacy and Stage. Results from multiple-sample confirmatory factor analyses suggested that gender subgroups could be treated as arising from the same population. Results also indicated that the tau equivalent model, instead of parallel model, was the preferred model for decisional balance and self-efficacy across the two BMI groups. Results supported the reliabilities and validities of the Decisional Balance Inventory and Weight Efficacy Questionnaire, and suggested that these measures are similar to the measures for US adolescents. These measures may be useful for developing and tailoring interventions to adolescents\u27 level of readiness for weight management