Testing stage effects in an ethnically diverse sample

Cross-validation of transtheoretical model smoking cessation measures in Chicago WIHS women smokers with and at risk for HIV

People with and at risk for HIV have high rates of smoking, increasing their morbidity and mortality. Effective cessation interventions are needed for this group. Transtheoretical model (TTM)-tailored interventions have demonstrated efficacy, but measures need cross-validation in this population. TTM cessation measures were evaluated in women smokers with and at risk for HIV (N = 111) from Chicago Women's Interagency HIV Study (WIHS). Confirmatory factor analyses evaluated measurement models. MANOVAs examined relationships between constructs and stage subgroups. For decisional balance, the two-factor uncorrelated model was best (χ2(20) = 13.96; comparative fit index [CFI], 1.0; root mean square error of approximation [RMSEA] = .00), with good (pros α = .78) and fair (cons α = .55) four-item alphas. The one-factor temptations model (α = .90) showed reasonable fit (χ2(18) = 80.22; CFI = .89; RMSEA = .177). Processes of change subscales had fair to good two-item alphas (α = .49-.77) and fit a 10-factor fully correlated model (χ2(125) = 222.72; CFI = .88; RMSEA = .084). MANOVAs by stage of change replicated expected patterns for the pros, overall temptations, and two process subscales with medium-sized effects (η2 = .06-.18). Contrary to expectations, no differences by stage were found for cons or temptation negative affect subscales. The structures of these TTM measures replicated with good internal and external validity, except for the cons, which needs refinement. Negative affect temptations was structurally sound, but did not vary by stage group potentially reflecting this sample's moderate depression levels and/or their reliance on smoking to deal with negative affect. Results support the use of most TTM measures in research and tailored interventions to increase smoking cessation among women smokers with and at risk for HIV and highlight the importance of managing negative affect in cessation materials targeting this group.

Stages of change, determinants, and mortality for smoking cessation in adult Taiwanese screenees

We aimed to investigate the associations between three smoking-related constructs (pros and cons of smoking, temptation to smoke, and self-efficacy of resisting smoking) and stage of change (precontemplation, contemplation, preparation, and action) based on the transtheoretical model among smokers attending a community-based screening program. We also assessed their effects on long-term all-cause mortality. A prospective cohort study, with an average of 7 years of follow-up, was conducted by enrolling 454 male smoking screenees. The comparisons of the mean score of each variable pertaining to three smoking-related constructs across four stages of smoking cessation were assessed by analysis of variance. The impacts of both smoking-related constructs and smoking cessation stage measured at baseline on 7-year mortality were assessed by using proportional hazards regression model. The differences in the mean scores of pros and cons of smoking, temptation to smoke, and self-efficacy of resisting smoking across four stages of smoking cessation were statistically significant (P < 0.01). The precontemplation group and the contemplation group as opposed to the action group increased the risk for all-cause mortality, but the size of effect was not statistically significant (P = 0.39) when age, duration of smoking, and three smoking- related constructs were controlled. Those with a lower social aspect of self-efficacy were approximately threefold [adjusted hazard ratio = 3.22 (95 % CI 1.26-8.21)] risk for all-cause death compared with those with a higher one. Three smoking-related constructs were highly associated with smoking cessation stage, and low self-efficacy was independently predictive of long-term mortality among male smokers attending a community-based screening program.

Reliability and validity of self-reported smoking in an anonymous online survey with young adults

OBJECTIVE

The Internet offers many potential benefits to conducting smoking and other health behavior research with young adults. Questions, however, remain regarding the psychometric properties of online self-reported smoking behaviors. The purpose of this study was to examine the reliability and validity of self-reported smoking and smoking-related cognitions obtained from an online survey.

METHODS

Young adults (N = 248) age 18 to 25 who had smoked at least 1 cigarette in the past 30 days were recruited online and completed a survey of tobacco and other substance use.

RESULTS

Measures of smoking behavior (quantity and frequency) and smoking-related expectancies demonstrated high internal consistency reliability. Measures of smoking behavior and smoking stage of change demonstrated strong concurrent criterion and divergent validity. Results for convergent validity varied by specific constructs measured. Estimates of smoking quantity, but not frequency, were comparable to those obtained from a nationally representative household interview among young adults.

CONCLUSIONS

These findings generally support the reliability and validity of online surveys of young adult smokers. Identified limitations may reflect issues specific to the measures rather than the online data collection methodology. Strategies to maximize the psychometric properties of online surveys with young adult smokers are discussed.

Validity of stage assessment in the adoption and maintenance of physical activity and fruit and vegetable consumption

OBJECTIVE

Stage assessments are examined to develop and test refined measurements that can be used for classifying individuals.

DESIGN

Stages were assessed in 1,850 persons in terms of their physical activity and dietary behaviors.

MAIN OUTCOME MEASURES

Stages for both behaviors were compared to behavior and other test variables. Misclassification, sensitivity, specificity, receiver-operation-curves, and discontinuity patterns were computed. Discontinuity patterns were tested with trends across stages and planned contrasts between adjacent stages.

RESULTS

In comparison to previous studies, sensitivity (70% to 80%) and specificity (80% to 87%) were high. When using lower level criteria (such as less intensive activity), sensitivity was lower, whereas specificity was higher. When behavioral maintenance was assessed, results suggested that the temporal cut-off point between action and maintenance was equally optimal at different cut-off points. Applying contrast analyses, nonlinear trends across the stages and a match of 87% of predictions of stage differences resulted.

CONCLUSION

Stage assumptions are supported in general, and refined stage assessment in particular. Levels of psychological variables (e.g., easiness, habit) may discriminate stages as well as or even better than temporal stage definitions.

Testing the predictive power of the transtheoretical model of behavior change applied to dietary fat intake

This study evaluated how well predictions from the transtheoretical model (TTM) generalized from smoking to diet. Longitudinal data were used from a randomized control trial on reducing dietary fat consumption in adults (n =1207) recruited from primary care practices. Predictive power was evaluated by making a priori predictions of the magnitude of change expected in the TTM constructs of temptation, pros and cons, and 10 processes of change when an individual transitions between the stages of change. Generalizability was evaluated by testing predictions based on smoking data. Three sets of predictions were made for each stage: Precontemplation (PC), Contemplation (C) and Preparation (PR) based on stage transition categories of no progress, progress and regression determined by stage at baseline versus stage at the 12-month follow-up. Univariate analysis of variance between stage transition groups was used to calculate the effect size [omega squared (omega(2))]. For diet predictions based on diet data, there was a high degree of confirmation: 92%, 95% and 92% for PC, C and PR, respectively. For diet predictions based on smoking data, 77%, 79% and 85% were confirmed, respectively, suggesting a moderate degree of generalizability. This study revised effect size estimates for future theory testing on the TTM applied to dietary fat.

Theory Testing Using Quantitative Predictions of Effect Size

Traditional Null Hypothesis Testing procedures are poorly adapted to theory testing. The methodology can mislead researchers in several ways, including: (a) a lack of power can result in an erroneous rejection of the theory; (b) the focus on directionality (ordinal tests) rather than more precise quantitative predictions limits the information gained; and (c) the misuse of probability values to indicate effect size. An alternative approach is proposed which involves employing the theory to generate explicit effect size predictions that are compared to the effect size estimates and related confidence intervals to test the theoretical predictions. This procedure is illustrated employing the Transtheoretical Model. Data from a sample (N = 3,967) of smokers from a large New England HMO system were used to test the model. There were a total of 15 predictions evaluated, each involving the relation between Stage of Change and one of the other 15 Transtheoretical Model variables. For each variable, omega-squared and the related confidence interval were calculated and compared to the predicted effect sizes. Eleven of the 15 predictions were confirmed, providing support for the theoretical model. Quantitative predictions represent a much more direct, informative, and strong test of a theory than the traditional test of significance.

Application of a stage based motivational interviewing approach to adolescent smoking cessation: the Transtheoretical Model-based study

OBJECTIVE

To evaluate the results of stage-based motivational interviewing (MI) efforts to help adolescents quit smoking using the three constructs of Transtheoretical Models (TTM). The validity of Turkish translations of two key scales was also assessed.

METHODS

A methodological and single group pre-post test study design was utilized. 275 adolescent smokers from one high school were recruited for validation of the scales and 60 of them participated in MI intervention. Change in smoking stage, interpretation of pros and cons of smoking, temptations, and smoking status were measured prior to the intervention, and follow-up was conducted at 3 and 6 months after intervention.

RESULTS

The scales showed adequate reliability and validity for use in Turkish adolescent. Of the MI participants, 40% and 55% had made positive movements in stage at 3 and 6 months, respectively. The interpretations of the cons of smoking significantly increased and temptations dropped toward the action stage at 3 months, and pros of smoking and temptations decreased at 6 months consistently with TTM. The percentages of those who had quit smoking at 3 and 6 months were 18.3% and 33.3% respectively.

CONCLUSION

A modest, short-term benefit of the intervention was provided to students towards stopping smoking and positive movement in stages was apparent.

PRACTICAL IMPLICATIONS

Using the MI principles in specific stages based on TTM, health care providers can influence and empower adolescent smokers positively for quitting smoking.

Donation intentions among African American college students: decisional balance and self-efficacy measures

Although the need for transplantation among African Americans is high, their donation rates are disproportionately low. This study describes the development and validation of culturally adapted psychosocial measures, including Transtheoretical Model constructs, Stages of Change, Decisional Balance, and Self-efficacy, related to deceased organ and tissue donation for an African American college population. Exploratory and confirmatory analyses for Decisional Balance and Self-efficacy measures demonstrated factor structures similar to previous studies of other behavioral applications, indicated excellent model fit and showed good internal and external validity. This study developed brief measures with good psychometric properties for an emerging behavior change domain in a new population.

Does stage-of-change predict dropout in a culturally diverse sample of adolescents admitted to inpatient substance-abuse treatment? A test of the Transtheoretical Model

The Transtheoretical Model (TTM) () proposes that the stages-of-change construct can serve as useful tool for identifying those most at-risk of treatment dropout [Prochaska, J. O. (1999). How do people change, and how can we change to help many more people? In M. A. Hubble, B. L. Duncan, & S. D. Miller (Eds.), The heart and soul of change (pp. 227-255). Washington: American Psychological Association]. While researchers have found mixed support for this claim in adult samples, studies have not yet tested this issue in adolescent substance-abuse treatment settings. This paper reports findings from a Canadian study of adolescents (n = 130: 80 Caucasians, 50 Aboriginals) admitted to a hospital-based, residential substance-abuse treatment program. Two approaches were used to test the TTM's claim: (1) a hierarchical logistic regression model of dropout was developed using the subscales of the University of Rhode Island Change Assessment instrument (URICA), demographic variables, and subscales of the Addiction Severity Index (ASI); and (2) a chi-square analysis was employed to test the hypothesized relation between stage-of-change and dropout status. The findings demonstrated that the best predictive model of dropout included only the Precontemplation subscale of the URICA (OR: 4.3; 95% CI: 2.0-9.0). In addition, adolescents assigned to the Precontemplation stage manifested significantly higher rates of treatment attrition than individuals in the Contemplation or Preparation/Action stages. This study provides important empirical support for the predictive utility of the stage-of-change construct among a culturally diverse sample of adolescents admitted to an inpatient substance-abuse treatment program.

Adolescents' smoking behavior and its relationships with psychological constructs based on transtheoretical model: a cross-sectional survey

BACKGROUND

Korean adolescents' smoking is currently being considered as a crucial factor determining the health status of adolescents and an important public health and social issue.

OBJECTIVES

The purpose of the study was to test the applicability of the Transtheoretical model to gain an understanding of smoking behavior change.

METHODS

A total of 706 adolescents who participated in the smoking cessation programs administered by the Korea Quit Smoking Association or Korean Association of Smoking & Health in 2003 were recruited. Four Korean-version questionnaires were used to identify the stages of smoking behavior and psychological attributes: Stage of Smoking Behavior Change Scale, Processes of Change Scale for Smoking, Decision Balance Scale for Smoking, and Self-efficacy Scale to avoid smoking.

RESULTS

Korean adolescents' smoking behavior was differed according to gender. In addition, the findings revealed that behavioral and cognitive processes of change, self-efficacy, and positives differed across the stages of smoking behavior, and that psychological constructs of the transtheoretical model had a statistically significant impact on smoking behavior change.

CONCLUSIONS

This research could spawn the development of theory-based and empirically supported smoking cessation intervention strategies and programs directed toward adolescents in the health care and nursing areas.

Differences in psychosocial variables by stage of change for fruits and vegetables in older adults

OBJECTIVE

To describe differences in demographic and psychological variables by stage of change for five servings of fruits and vegetables per day in older adults.

DESIGN

Cross-sectional survey with data collected in the participant's home or the project office by interviewers.

SUBJECTS

1,253 community-residing individuals 60 years or older (mean age=75 years) living in East Providence, RI.

MEASURES

Stage of change; decisional balance; processes of change; self-efficacy; dietary intake measured by the National Institutes of Health (NIH) Fruit and Vegetable Screener, the 5 A Day Screener, and the NIH Fat Scan; demographics; and anthropometrics.

STATISTICAL ANALYSES

Variables were compared by stage of change using analysis of variance for continuous variables and chi(2) analysis for categorical variables. Servings of fruits and vegetables were transformed (square root) prior to analyses.

RESULTS

There was a strong effect of stage of change on intake measured by the Fruit and Vegetable Screener [F(2, 1203)=109, P<.001, eta(2)=.154] and the 5 A Day Screener [F(2, 1203)=128, P<.001, eta(2)=.175] with a linear increase from precontemplation to action/maintenance. There was an overall stage effect on decisional balance, processes of change, and self-efficacy [Wilks's lambda=.703, F(30, 2132)=13.72, P<.001, multivariate eta(2)=.162], and significant univariate effects for all variables.

CONCLUSIONS

Self-assessed servings ("How many servings do you usually eat?") can be used for stage classification for older adults. Interventions for older adults in early stages should focus on increasing perceived benefits of healthful eating and cognitive process use. Self-efficacy as well as behavioral processes seem to be important in attaining maintenance.

A community-oriented primary care demonstration project: refining interventions for cardiovascular disease and diabetes

BACKGROUND

We describe a community-oriented primary care project that implemented all 5 steps of the formal model. Data are presented on cardiac risk factors, protective behaviors, health locus of control, and stage of readiness for change in an African American community. We discuss the use of these data to refine our health promotion interventions.

METHODS

We undertook a cross-sectional study of self-reported health behaviors from a door-to-door household survey of a geographically-defined community. Trained community members administered the survey questionnaire, which was completed in 386 of 557 randomly sampled households (response rate 69.4%). Qualitative discussions of survey results with 2 community groups were taped, transcribed, and analyzed for common themes.

RESULTS

Compared with their counterparts, respondents who were older than 65 years (P = .0006), who had hypertension (P <.0001), and who had diabetes (P = .001) had higher mean scores for powerful others locus of control. Rates for physical activity and low-fat diet indicators were low compared with national statistics. Most respondents reported a maintenance stage of change for exercise (46.2%) and diet (57.5%). Group discussions found lack of local exercise resources and high-quality grocery stores to be major barriers to health behavior change. Ministers and physicians were identified as important powerful others.

CONCLUSION

This study documents low rates of physical activity and healthy dietary patterns and describes recent interventions to address environmental barriers to behavior change. The association between powerful others locus of control and specific cardiac risk factors has prompted a greater emphasis on developing faith-based interventions and renewing physician-counseling efforts. Stage of readiness for change findings have prompted strategies to disseminate existing diet and physical activity recommendations more effectively.