Physical Activity Programs 1
The Effectiveness of Physical Activity Programs in Promoting Weight-Loss in
Obese Adults with Intellectual and Developmental Disabilities
Allison Sullivan
Temple University
The Effectiveness of Physical Activity Programs in Promoting Weight-Loss in Obese Adults with Intellectual and Developmental Disabilities
Obesity is a national epidemic. According to the Centers for Disease Control and Prevention (CDC), obesity is “common, serious, and costly”, with over one-third of adult Americans meeting the body mass index (BMI) criteria for this term (U. S. Department of Health and Human Services, 2001). Heart disease, stroke, diabetes, and some cancers are obesity-related conditions that the CDC considers some of the leading causes of preventable deaths. Substantial evidence exists to support the understanding that sedentary lifestyle is one of the most significant risk factors for obesity and one that can be successfully modified (U. S. Department of Health and Human Services, 2001). In light of these findings, numerous public health organizations and agencies such as the CDC (2001), the U.S. Office of the Surgeon General (2002) and the U. S. Department of Education, National Institute on Disability and Rehabilitation Research-Research Projects and Centers Program; Funding Priorities (2006) have sponsored a variety of initiatives to promote increased physical activity in the population.
As Stewart, et al. noted (2006), “Evidence for the effectiveness of community-level intervention to increase adult physical activity (PA) was reviewed by the Task Force on Community Preventive Services. Two “strong” recommendations were individually adapted health behavior-change programs and creating or improving access to places for PA, particularly in neighborhoods with the least resources... Individually tailored PA programs and interventions that include principles of behavior change were also featured in the recent Best Practices Statement for promoting PA in older adults developed by a coalition of national organizations led by The American College of Sports Medicine.Many initiatives emphasize the need to increase PA in underserved populations…primarily because these groups are at higher risk of poor health and have lower levels of PA than their counterparts”.
A vast amount of research exists on the subject of obesity, sedentary lifestyle, and appropriate methods for addressing these issues. There is so much research, in fact, that it is supremely challenging for any researcher investigating this topic to begin the process of critically appraising the quality of this body of evidence. The results reported in this literature can be of a contradictory nature. Many studies promote changes in dietary habits, for example, while other investigations assert that efforts to change the dietary habits of underserved groups, as well as within the population at large, is challenging and unsuccessful in the long-term due to limitations with resources and issues of self-determination (Bazzano et al., 2009; Ewing, et al., 2004; Chapman, et al., 2008; Heller et al., 2004)
A number of different techniques have been researched for the purposes of effecting weight-loss in the general population. Health education programs, nutrition counseling, gastric bypass surgery, resistance training programs, group exercise classes such as Zumba, mall walking programs, and interval training programshave all been identified as methods to promote weight loss.
One group in particular that faces multiple challenges in addressing the health-related risks of sedentary lifestyle are adults with intellectual and developmental disabilities. Adults with these disabilities are more likely to be people with low socioeconomic status and have neither the means nor the capability to access places for physical activity independently. Many individuals with these conditions require assistance with everyday life skills (Bazzano et al., 2009; Chapman, Craven, & Chadwick, 2005; Chapman, Craven, & Chadwick, 2008;Ewing, McDermott, Thomas-Koger, Whitner, & Pierce, 2004; Heller, Hsieh, & Rimmer, 2004; Marshall, McConkey, & Moore, 2002; Melville, et al., 2011; Saunders, et al., 2011). A large percentage of people with developmental or intellectual disabilities live in community residences, and staffs at these residences often have limited means or understanding regarding healthy meal preparation. According to Elinder, et al, (2010), “People with intellectual disabilities are more likely to have poor dietary habits, low physical activity, and weight disturbances”. A report by Bazzano, et. al. (2009), notes that people with intellectual and developmental disabilities have more chronic disease conditions than that of the general population, and are thus more costly to treat over their lifespan that members of the population at large. Although a significant amount of research exists on obesity and interventions designed to promote weight loss, very little research has been conducted to dateto identify those interventions that most effectively promote weight loss in this vulnerable group (Bodde, 2012, Melville, 2011).
As stated by the World Health Organization (WHO), “Physical activity is defined as any bodily movement produced by skeletal muscles that requires energy expenditure” (2009). Physical activity as an intervention is used to “promote weight loss and reduce or prevent the chronic complications of obesity” (Bazzano, et al., 2009). Increased physical activity has been shown to be an effective method for promoting weight-loss in obese adults(U. S. Department of Health and Human Services, 2001).
Thus, an evidenced-based practice review was conducted to investigate the effectiveness of research-based exercise programs in effectively promoting weight loss or slowing weight gain in adults with intellectual and developmental disabilities. Activity programs that promote weight loss were chosen as the intervention under investigation because adults with developmental disabilities are at high risk for obesity and related health problems. Physical activity level and obesity are risk factors for chronic health conditions such as heart disease, diabetes, and cancer that can be modified, and interventions which target these risk factors may be one significant approach toward improving health in this population (U.S. Office of the Surgeon General, 2002).
Methodology
An evidence based practice review was conducted to explore the question, “What are the effective exercise or activity-based interventions for promoting weight loss or preventing weight gain in obese or overweight adults with intellectual or developmental disabilities?”
Participants
Participants in the included studies ranged in age from 18 to 71 years old (Bazzano et al., 2009; Chapman, Craven, & Chadwick, 2005; Chapman, Craven, & Chadwick, 2008;Ewing, McDermott, Thomas-Koger, Whitner, & Pierce, 2004;Heller, Hsieh,Rimmer, 2004; Marshall, McConkey, & Moore, 2002; Melville, et al., 2011; Saunders, et al., 2011). One study included obese or overweight participants specifically diagnosed with Down syndrome (Heller, et al., 2004). Two studies included the same participants but reported on findings from different points in the study period(Chapman, et al., 2005; Chapman, et al., 2008). It should be noted, however, that although these two studies explicitly stated that the same participants were used in both studies, in the first study the authors utilized the term “learning disabilities” to describe the disabling condition of the participants, while in the 2008 study, the same authors used the term “intellectual disabilities” to describe the disabling condition of those participants.
In addition to the Chapman, et al. study from 2008, two studies included obese or overweight participants with identified “intellectual disabilities” (Marshall, et al., 2002; Melville, et al., 2011). One study included obese participants identified with “intellectual or developmental disabilities” (Saunders, et al., 2011). One study compared results of what the authors described as “normal learners” to that of “individuals with mental retardation” (Ewing, et al., 2004). One study included obese or overweight participants with identified “developmental disabilities”.
Interventions
All of the studies included a nutritional education component (Bazzano, et al, 2009; Chapman, et al. 2005; Chapman, et al., 2008; Ewing, et al., 2004; Heller et. al, 2004; Marshall, et al., 2002; Melville, et al., 2011; Saunders, et al., 2011). None of the studies measured physical activity without a dietary intervention component(Bazzano, et al, 2009; Chapman, et al. 2005; Chapman, et al., 2008; Ewing, et al., 2004; Heller et. al, 2004; Marshall, et al., 2002; Melville, et al., 2011; Saunders, et al., 2011). Two of the studies provided both nutrition and exercise information as well as supervised physical activity in a group format (Bazzano, et al., 2009; Heller et al. 2004). One study provided exercise and nutrition education in a group format with an optional recommended group walk (Ewing, et al., 2004). One study consisted exclusively of group education sessions, while“emphasizing the importance of exercise” (Marshall, et al., 2002). Four studies utilized individualized diets and exercise programs with home visit education sessions and data collection tasks, but no supervised exercise component (Chapman, et al. 2005; Chapman, et al., 2008; Melville, et al., 2011; Saunders, et al, 2011).
Outcome Measures
There were a variety of outcomes measures employed to examine the effectiveness of the interventions used. Four studies used Body Mass Index (BMI) and weight lost (Bazzano, et al., 2009; Marshall, et al., 2002; Melville, et al., 2011; Saunders, et al. 2011). TheBazzano, et al., 2009 study also included self- reported nutrition, physical activity, and life satisfaction measures. The Melville, et al., 2011 study included measures of physical activity and sedentary behavior in addition to BMI and weight lost.
The two studies that were a longitudinal comparison of the same subjects used BMI exclusively (Chapman, et al. 2005; Chapman, et al, 2008). One study used BMI in addition to pre and post -test measures of knowledge of healthy eating choices (Ewing, et al, 2004). One study used Likert scales for rating health status and Instrumental and Activities of Daily Living Scales completed by a guardian, as well as self-report measures including the Cognitive-Emotional Barriers to Exercise Scale, Exercise Perception Scale, a non-standardized measure of self-efficacy, Life Satisfaction Scale, and an adapted Children’s Depression Inventory (Heller, et. al, 2004). This study did not report on BMI or weight loss as an outcome measureof the study.
Search Strategies
Relevant research articles were identified via computer-assisted search of online databases. The following search terms and key words were utilized in various combinations:intellectual disabilities, developmental disabilities, obesity, weight gain, exercise, physical activity, and intervention. Search terms that were combined to yield significant results included: (intellectual or developmental) and disabilities, obesity or weight gain, and exercise orphysical activity; and (intellectualor developmental)and disabilities, obesityor weight gain, exercise or physical activity, and intervention. The electronic databases that were searched includedAcademic Search Premier, CINAHL with Full Text, Health Source: Nursing/Academic Edition, MEDLINE, OT Search, PsycARTICLES, Psychology and Behavioral Sciences Collection, and PsycINFO. The online search yielded 15 studies, seven of which were included for review. A citation review was conducted by hand after the articles from the database search were obtained, and one additional study was located via this hand search.
Inclusion and exclusion criteria for the search
Research articles published after 2002 were included in the review. All studies included explored aspects of physical activity as an intervention. Due to the very limited number of published studies in this area, studies with combined interventions were included. Studies that reported adult subjects with overweight and obese body mass index were included in the review. Literature had to be published in English to be included. Studies that were exclusively correlational or descriptive in nature were excluded from review. Studies that were not completed on subjects with developmental or intellectual disabilities were excluded. Expert opinion articles with no sample studied were excluded.
Data collection and analysis
All eight of the studies included in this review used quantitative data to describe their results. Three of the studies compared experimental groups to control groups (Chapman et al., 2004; Chapman, et al., 2008; and Heller, et al., 2004). One of the studies was a randomized control trial (Heller, et al., 2004). Two studies followed a nonrandomized comparison group design (Chapman et al., 2004; Chapman, et al., 2008) One study utilized a case-controlled, nonrandomized pretest-posttest design (Ewing, et al., 2004). Four studies followed a single group, pretest- posttest design (Bazzano, et al., 2009; Marshall, et al., 2003; Melville, et al., 2011; Saunders, et al., 2011). None of the studies incorporated blinding into the study designs. One study gathered follow-up data after the completion of the intervention (Melville, et al., 2011).
The eight studies utilized a variety of methods for analyzing data. Three studies used Analysis of Covariance (ANCOVA) to test the effects of diet and exercise on weight loss (Chapman et al., 2004; Chapman, et al., 2008; and Heller, et al., 2004). Four studies employed paired t-tests to analyze pretest-posttest data group means (Bazzano, et al., 2009; Ewing, et.al, 2004; Marshall, et al., 2003; Melville, et al., 2011). Three studies used McNemar’s test for this reason as well (Ewing, et al., 2004; Heller et al., 2004; Melville, et al., 2011). Three studies reported Chi-squared test results to describe the distribution of the sample and detect differences in the group demographic differences (Bazzano, et al., 2009; Ewing, et al., 2004; Heller, et al., 2004).
One study used the Wilcoxon Signed Rank Test to analyze some measures of physical activity for which the distribution was skewed (Melville, et al., 2011). One study employed a Type III sum of squares as adjusted measures because the number of participants in intervention and control groups was different (Heller, et al., 2004). This same study also reported the Cronbach’s alpha reliability to describe the Likert scale measures that were used (Heller, et al., 2004). One study did not utilize inferential statistics to analyze the data (Saunders, et al., 2011). This study reported the average percent of weight loss by living arrangement, diagnosis, and gender for the sample, but did not utilize a statistical package to analyze the results beyond stating that these results were comparable to the “recommended 7% weight loss by theof the Diabetes Prevention Program” (Saunders, et al., 2011).
Results
Overall, the research studies in this review display limited effectiveness in their interventions’ successes inpromoting weight loss in adults with developmental disabilities. In this review, only one randomized controlled trial has been completed to measure the benefits of an exercise and nutritional education program with adults with Down syndrome, and this particular study did not investigate the effectiveness of the program in promoting weight loss, reporting instead on psychosocial factors such as the life satisfaction and sense of self-efficacy of its participants (Heller, et al., 2009). Since each of the interventions described in this review are so different from one another, it is very difficult to draw conclusions with any true confidence regarding the ultimate ability of an exercise-based intervention to promote sustainable weight loss in adults with intellectual disabilities.
In fact, the two studies by Chapman, et al. (2005 and 2008, respectively) reported on the same group of participants at one year and at 6 years using this intervention, and demonstrated diminishing returns over time. Although the amount of weight lost for the intervention group was significant after one year in the study, after six years of the intervention, the rate of weight loss for the intervention group was no different from that of the control group.
All of the studies did demonstrate the ability of participants to lose weight during the study period. With no follow-up data from seven of these studies, however, it is not possible to determine whether these results were sustainable or whether the techniques used might be applicable to the population of adults with developmental disabilities at large. (Bazzano, et al, 2009; Chapman, et al. 2005; Chapman, et al., 2008; Ewing, et al., 2004; Heller et. al, 2004; Marshall, et al., 2002, 2011; Saunders, et al., 2011). Of this group, five of the studies emphasized diet supervision and encouraged exercise but the exercise component was not supervised by the study team (Chapman et al., 2005; Chapman, et al., 2008, Marshall, et al., 2003; Melville, et al., 2011; Saunders, et al., 2011).
Only two of these studies actually provided supervised exercise instruction as a component of the intervention (Bazzano, et al., 2009; Heller, et al., 2004). One study had a supervised walking component, but this was optional for participants (Ewing, et al., 2004). Bazzano, et al. (2009) did demonstrate significant weight loss in 67% of study subjects and both the Bazzano, et al. (2009) and Heller, et al. (2004) studies showed significant improvements in participants’ life satisfaction. While these two studies showed promising results for their participants, they are very small studies completed over fairly short periods of timewith no follow-up and have limited generalizability for these reasons.
Discussion and Clinical Implications
The results of this evidence- based practice review regarding the effectiveness of activity-based interventions in promoting weight loss in adults with developmental disabilities indicates that there is still much to be learned about the usefulness and best methods for this type of intervention with this population. All eight of these studies show that activity can promote weight loss in adults with intellectual disabilities. Since seven of the eight studies lacked follow-up data, however, it is not possible to state with confidence whether programs of this nature produce lasting benefits. Additionally, since the nature and format of each of these interventions was so vastly different, it is almost impossible to compare them to one another in any way that allows the critical appraiser to make any generalizations of substance about their results.
Adults with intellectual disabilities are an under-studied group of individuals in our population. The amount of research regarding exercise with this group is very limited. Further research is needed to determine whether or not exercise-based interventions can promote weight loss or prevent weight gain in adults with these disabling conditions.
Implications for Consumers
Activity based interventions for obese adults with developmental disabilities have not been shown conclusively to promote sustainable weight loss. A healthcare provider may implement an activity program to promote weight loss, but outcomes are inconsistent. Due to the many co-morbid health factors associated with obesity and developmental disability, a caregiver should seek a physician’s advice before embarking on any efforts to promote weight loss in the individuals under their care, with regard to both diet and exercise guidelines.
Implications for Practitioners
Exercise-based activity programs may promote weight loss and prevent weight gain in obese adults with developmental disabilities. There is insufficient evidence at this time to conclude that any one specific method is the most effective method to promote weight loss. It is highly likely, however, that some obese individuals with developmental disabilities can and will lose weight as a result of an exercise-based intervention, but this is not yet reinforced in evidenced based literature. What is known, however, is that doing nothing almost guarantees negative health outcomes in this vulnerable population.