Does Stage of Change Predict Outcomes? Essay Example

Introduction

“Globesity”—the pandemic of people being overweight and/or obese—is a public health problem.¹ More than 115 million people suffer from obesity-related problems worldwide,¹ including chronic cardiovascular disease, diabetes, and hypertension.^{2, 3} Between 2007 and 2008, an estimated 34% of Americans aged 20 years and older were overweight, 34% were obese, and 6% were morbidly obese.⁴ In the state of New Jersey, the prevalence of obesity in 2010 was 24%, which was less than the national level.⁵ According to the 2009 report from the Centers for Disease Control and Prevention (CDC),⁶ direct and indirect annual costs of obesity were reported to be as high as $147 billion. Obesity-related direct expenditures are expected to account for more than 21% of the nation’s direct health care spending by 2018.⁷ If the rising rate of obesity could be halted, an estimated $200 billion in health care costs could be saved by 2018.⁷

Healthy People is a 10-year national science-based objective to promote health and disease prevention in the American public.⁸ Since the late 1970s, Healthy People has set national health objectives to “meet a broad range of health needs, encourage collaborations across sectors, guide individuals toward making informed health decisions, and measure the impact of our prevention activity.”⁸ One of the objectives of Healthy People 2010 was to reduce the rate of obesity within the adult population to 15%. Unfortunately, no state met this goal, and the overall prevalence of obesity among U.S. adults continues to increase, as reported by the CDC in 2009.⁹ As part of the public health initiative, one of the goals in the Healthy People 2020 is to establish nutrition and weight management counseling in the workplace to help reduce the percentage of adults with obesity.⁸

The prevalence of obesity and obesity-related chronic diseases has become an occupational health concern as recognized by the National Institute for Occupational and Safety.¹⁰ Worksite-wellness programs have become an area of interest to employees and employers because of their demonstrated effectiveness in improving health benefits, not only by decreasing total health risk ^2,11 but also lowering medical costs.¹² The American Heart Association (AHA) promotes and endorses comprehensive worksite-wellness programs to address the public health crisis in the areas of cardiovascular disease and stroke prevention.¹³ Implementation of effective worksite-wellness programs for weight management are found to benefit both employers and employees.¹⁴

The AHA also recommends assessing readiness to make behavioral changes to focus the individual’s skill development as an integrated part of workplace programs.¹³ The Transtheoretical model (TTM), one of the most commonly used models for studying behavioral change,¹⁵ is a behavioral theory used to determine whether an individual is ready to change to a healthier lifestyle.¹⁶ A study conducted from 2006 to 2008 by the Institute for Nutrition Interventions at the School of Health Related Professions (SHRP) of the University of Medicine and Dentistry of New Jersey (UMDNJ) determined the impact of a 12-week worksite wellness program on overweight and obese employees using in-person and Internet-based approaches.¹⁷ Although the UMDNJ trial found positive changes in clinical outcomes including weight loss, changes in body fat, waist circumference, cholesterol levels, and blood pressure in both men and women,¹⁷ participants’ stages of change (SOC) were collected in the original trial. Currently, this data has not yet been explored. It is important to explore SOC to better design and develop future interventions for worksite wellness programs and to help facilitate health care providers establish appropriate goals and action plans to transition participants, according to their readiness to change.

The primary aim of the study is to examine how does SOC regarding eating behavior predict changes in weight, waist circumference, and body fat percentage among overweight and obese employees in a 12-week worksite intervention program.

Methodology

Study Design and Sample Description

Institutional Review Board approval was granted from the University of Medicine and Dentistry of New Jersey-Newark. This study used the closed data set from the original 12-week worksite wellness clinical trial conducted between 2006 and 2008 at UMDNJ using two different modes of delivery: In-person (IP; Newark campus) and Internet-based (IB; Piscataway campus)—with follow-up at weeks 26 and 52. All study participants were employees of UMDNJ’s Newark and Piscataway/New Brunswick campuses. Employees were 18 years and older with a minimum BMI equal to and/or greater than 25.0 kg/m². At baseline, 137 adult men and women participants were voluntarily enrolled in the study. There were 95 participants who completed at baseline and 12 weekly intervention followed by 74 participants who completed the study at week 52.

Study Intervention

All participants met with an RD for individual sessions at baseline (week 1), week 6, and week 12 for data collection, counseling, and education. A minimal counseling and education were provided and limited data were collected at week 6. Individual sessions included a face-to-face interaction between a participant and the RD to establish an individual’s goals to meet his or her dietary needs and physical activity changes.¹⁷ Individual sessions also included completion of data collection such as health and nutrition histories, anthropometric, finger stick blood glucose, and lipid measurements, as well as a 24-hour diet recall. Individualized tailored diets were designed to meet participants’ dietary patterns, food preferences, and energy needs for weight loss. The 12 weekly face-to-face 50-minute group sessions focusing on diet, physical activity, and chronic disease risk reduction were provided to participants of the IP group. Group sessions also integrated education, discussions, a question and answer period, weigh-in and interaction with the study RD. All participants received reminders via e-mail and telephone concerning their individual appointments. E-mail reminders were distributed to participants before the weekly sessions.  At weekly weigh-ins, water bottles, lunch bags, t-shirts, Thera-bands, and 100-cal food pack samples were provided to participants as part of program incentives.

In the IP group, weekly live group sessions were provided for all participants for 12 consecutive weeks during lunchtime on the Newark campus. The participants in the IB group received the same sessions, except information and discussion was delivered online via WebCT (a distance learning platform for participants in the wellness program).²¹ Educational materials given to the IP participants at weekly sessions were the same as those provided to IB participants. Participants came to their respective campus for a weigh-in, once a week for 12 weeks.

The diet education materials provided to participants was based on the Dietary Guidelines for Americans 2005, which is consistent with the recommendations from the AHA and the National Heart, Lung, and Blood Institute (NHLBI) Dietary Approaches to Stop Hypertension (DASH) diet. The DASH diet focuses on increased dietary fiber through fruits, vegetables, whole grains, nuts, and seeds; lower total fat with less than 300 mg dietary cholesterol; reduced sodium and low fat sources of protein and dairy products to achieve and maintain a desirable body weight.⁷⁰ The 12-week education intervention (Appendix A) highlighted the key topics of healthful eating, portion control, dining out, exercise, goal setting, and strategies for stress and food management. Participants were encouraged to do 30 minutes physical activity daily. A pedometer was given to each participant to record steps. The study RD utilized tape measure to obtain waist circumference in inches. The Tanita Bioelectrical Impedance Analysis (BIA) quadruplex was utilized to measure participants’ weight in pounds and body fat in %. These measurements were taken at baseline, weeks 12 and 52 for obtaining comparative data. Prior to measurements, participants were asked to remove shoes, belts, and outer clothing with emptied pockets.

Demographic Characteristics

Demographic characteristics including age, gender, ethnicity or race, history of chronic diseases, and type of delivery were included in the “Subject Data Sheet” (see Appendix B) which was created by the researchers from the original study.¹⁷

Healthy Eating Stage of Change Instrument

The use of the Healthy Eating Stage of Change (SOC) instrument in the original study was based on the study conducted by Hargreaves et al., ⁷¹ which assessed SOC regarding dietary fat intake (see Appendix C). The instrument used to measure the healthy eating SOC was composed of five dichotomous questions to measure participants’ intentions concerning healthful eating.⁷¹ Participants were asked to identify their readiness to eat a healthy diet using a scale of 1?5 at baseline, weeks 12 and 52. Each number reflected a healthy eating SOC based on TTM, with 1 indicating not ready to change or to plan to eat a healthy diet and 5 indicating a healthy diet is being followed and plan to maintain a healthy diet in the next 6 months.⁷¹ Participants were classified into 5 stages derived from TTM to reflect their healthy-eating stages at each time point: baseline, week 12, and week 52.

Clinical Outcome Variables

Weight (measured in pounds), waist circumference (measured in inches), and body fat (measured in %) were included in this study as clinical outcome measurements at baseline, week12, and week 52.  Changes in weight, waist circumference, and body fat percentage between baseline and week 12 and baseline and week 52 were analyzed.

Inclusion and Exclusion Criteria

The inclusion criteria of this study were male and female adults, 18 years of age or older, who have a BMI greater than or equal to 25 mg/m². All participants who finished, at a minimum, the 12-week intervention and those who returned to the follow up at week 52 were included in this study.

Statistical Power

The primary clinical outcome measures of this study are weight, body fat %, and waist circumference. Using G*Power version 3.0, a medium size (0.25) for three groups at three time points required a total sample size of 36 participants to ensure substantial power (0.9) for ANOVA repeated measures within-subjects.  Comparisons for ANOVA repeated measures between-subjects, using a medium effect size  (0.25) to assure substantial power (0.9) required a total sample size of 72 participants between groups.  Using a medium size (0.25) required 54 participants in each group to assure substantial power (0.9) for within-between interaction.

Statistical Analysis

All analyses were performed using SPSS for Windows, version 19.0. A priori alpha was set at P ? 0.05.  Descriptive analyses included frequent distributions, n and percent for categorical data (gender, race, history of chronic diseases, and SOC) and mean, standard deviation and range for continuous variable (age, weight, body fat %, and waist circumference). Paired t-test analyses were used to examine the changes of clinical outcomes between two time periods (baseline to 12-weeks and baseline to 52-weeks).

A General Linear Model with repeated measures was used to compare the within and between subjects over time to determine the effect, if any of SOC on the clinical outcome measures.

Box plots and Shapiro-Wilk test were applied to test for normality of data. Although data were not normally distributed in the clinical outcome measures in relation to age, repeated measures’ analyses was used since it was robust to violations of normality. Outliers were defined as more or less than three times the inter-quartile range for distribution. (Weinberg) There were 2-4 outliers for weight, 1-5 for body fat %, and 3-4 for waist circumference, identified over time. Analyses were completed with the data from outliers because the PI of this study expected that there could be extreme participants in the study due to the fact that the targeted population comprised of obese individuals.

Results

Demographic Characteristics

The number of enrolled participants in the worksite wellness program was 137 (n=137). 95 participants (69%) completed the 12-weekly intervention, and 74 (54%) completed the 52 weeks follow-up. Twenty-one of the participants left the program before completing the 52 weeks follow up due to multifarious factors. Table 1 depicts the demographic characteristics. Majority of the participants (92.6%, n=88) were female, 52.6% (n=50) were white and 47.4% (n=45) were non-white. As participants were a fair representation from all ethnic groups, differences due to ethnicity or race are unlikely to emerge. The mode of delivery of interventions was equally distributed with half the participants receiving instructions in-person, and the other half through internet. Preexistence  of lifestyle diseases like hypertension, Diabetes Type II and dyslipidemia in a significant fraction of the participants was identified as a factor which could affect outcomes of this study. The data of preexisting conditions is given in Table 1.

The participants’ age range was 23-65 years with a mean age of 47.4 years (SD=10) and depicts middle age at which habits are usually permanent and compliance with instruction could be a factor needing high motivation. Shapiro-Wilk indicates that the data significantly deviates from normal distribution (p=0.004); however, this was considered acceptable because the study design involved recruitment of a target population within 18-65 years. There were no extreme outliers as identified by the box plot for age.

Stages of Change Regarding Eating Behavior

Descriptive statistics was used for analysis of SOC data for each participant. Table 2 displays participants’ SOC regarding their eating behavior at three different points of time: Baseline, Week 12 and Week 52. The data shows that percentage of participants either in the pre-contemplation or the contemplation stage was nonexistent at the three time points of measurement.

At baseline, most participants classified themselves in preparation stage (73.7%, n=70) followed by maintenance stage (14.7%, n=14) and action stage (10.5%, n=10). At Week 12, 62 participants changed from preparation stage to action stage while 18 changed to maintenance stage. The SOC data suggests that the majority (65.3%) of them were already shifting from preparation stage into the action stage by week 12.  At 52 weeks, nearly half of the participants (48.6%, n=36) classified themselves in maintenance stage, action stage (28.4%, n=21), preparation stage (21.6%, n=16), contemplation stage (1.4%, n=1), respectively. No participants were classified in precontemplation stage by week 52.

Outcome Measures

Table 3 displays participant outcome measures at baseline, Week 12 and Week 52. Descriptive statistics was employed to determine the mean, minimum, maximum, and standard deviation for the outcome variables of weight, waist circumference, and body fat percentage at all stages. From baseline to Week 52, mean weight reduced from 194.38 lbs to 199.04 lbs (mean), body fat was reduced from 41.7% to 40.8% (mean) and waist circumference reduced from 40.4 inches to 38.6 inches (mean).  Box plots were generated to identify extreme outliers for the outcome variables: weight, body fat%, and WC.  Several extreme outliers were found but they were included in the analysis as the target was to conduct the study in obese individuals.

Change in participants’ weight, waist circumference, and body fat percentage

Paired-sample t-test was employed to evaluate changes, if any in weight, waist circumference, and body fat %. Table 4 displays the mean change in participants’ outcome measures at baseline, Week 12 and Week 52. There was significant improvement in all outcome measures as suggested by the figures depicted in the Table 4.  Analyses of paired comparison indicated weight loss, which was significantly reduced from baseline to Week 12, with an average loss of 4.5 lbs (p<0.0001). Paired analysis also yielded a significant reduction in body fat as the percentage dropped by an average of 0.9% from baseline to Week 12 (p<0.0001). Waist circumference also showed significant reduction. From a baseline average level of 40.4 inches it reduced to an average of 39.03 inches at Week 12 (p<0.0001), and 38.60 inches at Week 52 ( p<0.0001).

Effects of SOC on Outcome Measures

A general linear model with repeated measures was conducted to assess the effect of SOC on outcome measures from the baseline to Weeks’ 12 and 52. Mauchly’s Test of Sphericity identified that sphericity was violated in all measures (p < 0.05); Greenhouse-Geisser test for correctional adjustment however showed that F statistics in within-subjects test confirmed the statistical significance in weight, body fat, and WC outcomes across the three measures which were found to be statistically significant.

The main effect within-subjects for the weight measure was significant (F=1.72, p=0.007). Post hoc comparison revealed a significant decrease in weight from baseline to weeks 12 and 52 (Table 4). No interaction effect was detected for weight changes among the three groups in SOC (preparation, action, and maintenance groups); the changes in weight for the three groups in SOC were not different across time.

The within-subjects’ test also indicated that there was a significant main effect on body fat % (F=1.76, p=0.002). Post hoc comparisons demonstrated a significant decrease in body fat % from baseline to week 12 (Table 4). No interaction effect was identified for body fat % change across the three groups in SOC; the changes in body fat % for the groups in SOC were similar over time.

A similar pattern reflected significant main effect on waist circumference for all subjects over time (F=1.63, p= 0.000). Post hoc comparison revealed a significant decrease in WC from baseline to weeks 12 and 52 (Table 4). However, the interaction of time and SOC was not significant; the groups had the same pattern of change in WC across time.

Levene’s Test confirmed that variance was not equal for each level of the repeated measures ( p >0.05). The between-subjects test indicated that there was no statistically significant difference detected in weight (F=1.31, p=0.276), body fat % (F=2.81, p=0.067), and WC (F=2.68, p=0.071) across groups in SOC. The results of the Post Hoc tests demonstrated that SOC did not have any significant effect on weight, BF%, and WC changes across all three repeated measures.

Discussion

The primary goal for this retrospective study was to investigate the effect of SOC on clinical outcome measures of weight, body fat %, and waist circumference among overweight and obese employees participating in a 52 Week long intervention program delivered by two different modes.

This is the first worksite wellness study using SOC’s based on the Transtheoretical  model (TTM)  to predict clinical outcomes specifically targeting overweight and obese individuals.

As hypothesized, baseline SOC regarding eating behavior does not predict change in weight, body fat, and waist circumference from baseline to weeks 12 and 52; indicating no treatment effect of SOC on anthropometric measures.

The results of this study indicated that all participants achieved significant weight, body fat, and waist circumference reduction over 12 weeks.

Independent of each stage of change group, there was a positive shift change observed from baseline to week 12; majority of participants were able to change from preparation stage to action stage by 12 weeks. Preparation, action and maintenance stages of SOC are the foci to which most participants belong in this study. The shifting of stages of changes over time suggests that the worksite wellness intervention provided by the RD was effective and the participants’ comprehension and motivation to eat and live healthy as observed from the evidence of forward shifting of the stages over time.

A similar quasi-experimental intervention lasting two years and carried out on 1,111 obese participants showed that no statistically significant differences in outcomes were discernible when the interventions were individually managed as compared to those exposed to only environmental interventions (Dejoy et al, 2011). This suggests motivation and constant contact are more important in getting desired outcomes and not the duration. A shorter, 12 week walking program was able to significantly alter the BMI and blood cholesterol levels towards a favorable direction in a group of 120 participants selected from the college staff in another study further corroborating the importance of compliance and close supervision over a shorter span of time (Haines, 2007). It shows that the participants in such a study when aware about the desired positive outcomes of an intervention can be motivated at the outset, automatically eliciting a SOC at the outset of the program. The higher percentage of action and maintenance SOC at the 12 Week stage in our study shows that the interventions by the RD were able to motivate the participants.  Significant improvement in the reduction of body fat, HDL, BP, and improvement in quality of life scores was demonstrated in another prospective randomized study, in which the intervention group showed better results as compared to the control group (Milani et al, 2009). This study had a total duration of 12 months (Milani et al ,2009). A two year obesity intervention program practiced primarily on women participants was able to elicit significant reduction in BMI and waist/hip ratio (Siegel et al, 2010). As the majority of participants in our study were also women, it substantiates the positive outcomes obtained in 12 month long study by Milani et al (2009).  The ability of the program administrator to maintain constant contact with the participant, self motivation and education are therefore the prime factors which can affect outcomes in such studies. In our study direct interaction as well as indirect contact through internet were used for instruction, which proved instrumental in motivating the participants as their SOC improved to ‘action’ and ‘maintenance’ stages at Week 12.

The demographic characteristics of the participants suggest there was a representative sample required for this study. Occurrence of lifestyle diseases like hypertension, Diabetes Type II and dyslipidemia in a significant fraction of the participants could however affect the outcomes of this study as such conditions might require medications, which can produce side effects affecting behavior and compliance.

Hypertension and dyslipidemia were the major comorbidities which might have affected the results in this study. Participants with comorbidities affecting compliance need to be eliminated from such studies as they might yield data inconsistent with the real design of this study due to issues, which might affect their outcome measure evaluation.

Limitations

There are a number of limitations to this study. One potential limitation of this study was the self-reported questionnaire on healthy eating behavior completed by the subjects. Therefore, the study may have been susceptible to reporting bias. Additionally, due to the nature of voluntary participation in the study and participants were being measured with body compositions which could have been more motivated to make changes. Missing data documentation may also be a potential limitation of this study. The total sample for the data analysis was reduced to 95 participants. The attrition rate was high, with 54% of participant returned for 52-week outcome measure. Besides the study sample was primarily women, the use of a self-selected sample from the university setting also limited the generalization of study findings. Another limitation of this study was the lack of a control group that received no intervention.

Despite the limitations, there are several strengths of this study including random assignment of participants from different campuses. There are very limited outcome studies using SOC to predict body composition changes in a worksite setting. This may prompt researchers to replicate similar outcome study at variety of worksite settings. Lastly, the SOC model is one of the common tools to use measuring behavioral change and the SOC survey tool was previously validated.

Conclusions

The results of this research suggest that a 12-week worksite wellness is effective in improving clinical outcomes of weight, body fat, and waist circumference. Participants were able to lose weight, body fat, and reduce waist circumference over 12 weeks and continue to reduce waist circumference over 52 week. There were no differences were observed based on the SOC (precontemplation, contempletation, preparation, action, and maintenance), however, there was a positive shifting in stages observed overtime.

Implications for practice

Understanding the readiness to change regarding eating behavior can help delivery effective interventions when counseling clients according to their readiness to change. Registered Dietitians and other health care providers may integrate the SOC model when developing interventions for their weight management or wellness programs to move them forward regarding their readiness to change. Constant contact, appropriate educational strategies’ and self-motivation seem to be the vital factors affecting outcomes in regards to their SOC.

Implications for research

Additional research is desirable with a larger sample size and a diverse sample.