Collection of Data
Clinicians are in concurrence that severe obesity is now a prevalent problem among many people (Flegal, Carroll & Ogden, 2010, p.235). The prevalence of severe obesity is synonymous to other medical conditions such as diabetes as well as high blood pressure (hypertension). Although doctors are currently using pharmacotherapy and bariatric surgery to treat severe obesity, a limited number of clinical trials have been done to assess the possible treatment of this condition. It is against this background that Bret H. Goodpaster and colleagues carried out a randomized trial to establish the effectiveness of a weight loss and physical activity in alleviating the adverse health risks associated with severe obesity (Goodpaster, Delany & Otto, 2010, p.1795).
The study carried out by Goodpaster and colleagues was based at the University of Petersburg. This study was a single-blind randomized trial carried out between February 2007 and April 2010 at the academic institution. The researchers recruited 130 adult participants from the community suffering from type II and III severe obese without diabetes. It is worthy to note that 37% of the participants were African America adults. The participants were subjected to a rigorous lifestyle intervention (encompassing diet as well as physical activity) for a period of one year. The first set of participants (initial-activity group) was randomized to diet as well as physical activity for a period of one year. The second set of participants (delayed-physical activity group) was subjected to a uniform diet but the physical activity was postponed for 6 months. The primary outcome of interest was changes in weight. Secondary outcomes such as hepatic fat content, abdominal adipose tissue, waist circumference as well as cardio-metabolic risk were also assessed (Goodpaster, Delany & Otto, 2010, p.1795).
The main outcome of the study was accurately measured. This is evidenced by the completion rate of the study. For example, 78% (or 101) of the 130 participants took part in the 12-month follow-up appraisal. It is worthy to note that both groups lost a considerable amount of weight within the first 6 months. Nonetheless, the first group (initial physical activity group) lost considerably more weight (10.91kg at 95% CI, 9.2-12.6) within the first 6 months compared to the second group (delayed-activity group) which lost 8.21kg (95% confidence interval, 6.4-9.9). In addition, both group reported reduced levels of visceral abdominal fat, waist circumference, blood pressure, insulin resistance as well as hepatic fat content (Goodpaster, Delany & Otto, 2010, p.1795).
Goodpaster and colleagues carried out a 1-year randomized trial to study the impacts of a rigorous lifestyle as well as dietary interventions on weight loss among adult people with severe obesity. The researchers wanted to find out whether a dietary intervention program (and physical activity exercise) would result in weight loss and compared these outcomes with those of a dietary intervention alone. The study wanted to establish whether the outcomes of the African American people differed from those of white people. The study also evaluated variations in cardio-metabolic risk factors, hepatic fat content as well as waist circumference (Goodpaster, Delany & Otto, 2010, p.1796).
The researchers used newspaper and television advertisements as well as mass mailing to select participants. In addition, the human ethics committee of the university evaluated and endorsed the study. The recruitment exercise started in February 2007 and the data collection exercise was completed and ready for analysis by April 2010. The participants were required to submit their written informed consent prior to their participation in the study. The researchers selected only people with severe obesity and within the 30-55 age groups. In addition, participants were required to adhere to the intervention and evaluation visits, be able to walk without help and secure medical consent to take part in the study. The study also exempted participants who had suffered from cancer in the last five years, had enlisted in an official weight reduction program in the last one year or were receiving medical therapy for coronary artery ailment. Participants were also excluded from the study if they were pregnant in the last six months. Any candidate suffering from unrestrained diabetes and hypertension was also exempted from taking part in the study (Goodpaster, Delany & Otto, 2010, p.1796).
The study enlisted130 participants who were divided into 2 groups on a random basis. Participants were divided in terms of race/ethnicity (whites and African Americans), level of obesity (type II or III) and sex. Intervention assignment was based on the race/ethnicity to ensure that participants from different races and ethnic groups were equally represented in the groups. There was no bias in data collection since the study was single-blind. The participant group assignment was also kept confidential from the assessors. All outcomes data were kept secret for 12 months until the final data was recorded and evaluation done (Goodpaster, Delany & Otto, 2010, p.1796).
Analysis of Data
The researchers used X2 tests to analyze categorical variables. The study also used SAS version 9.2-with the type I error margin fixed at.05 (2-tailed test) – to analyze primary and secondary outcomes. The missing data was imputed using the Markov chain Monte Carlo model. This model produced a total of 10 imputations. In addition, a variety of mixed-effects models were used for both the primary and secondary outcomes and quantified repetitively at baselines. The study also examined the major effects of treatment group and time (including treatment group and time interaction effect) in the mixed effect models via the unstructured dependence structure. The study used the mixed effect models to generate the least square data. The study also used PROC MIANALYZE procedure in SAS to merge results from each imputation. It is worthy to note that the participants were randomized to establish an ample sample which could be used to detect the projected differences in terms of weight loss at 6 months and at 12 months (Goodpaster, Delany & Otto, 2010, p.1797).
Interpretation of Data
The researchers found that the retention rates were not significantly different between the two groups. For example, the retention rates for the first group (initial-activity group) were approximately 90% and 73% at 6 months and 12 months intervals respectively. On the other hand, the retention rates for the second group (delayed-activity group) were approximately 90% and 83% at 6 months and 12 months intervals respectively. The researchers also did not find major demographic differences among the participants enlisted in the study (Goodpaster, Delany & Otto, 2010, p.1798). In addition, the prevalence of racial/ethnic differences with respect to body fat (or body weight) was minimal. In fact, there were no remarkable differences between those participants who opted out of the study and those who completed the intervention program. However, both groups (initial-activity group and delayed-activity group) lost a considerable amount of weight at 6 months. For example, the initial-activity group lost 10.9kg at 95% confidence interval whereas the delayed-activity group lost 8.2kg at 95% confidence interval within the first 6 months. In addition, the first group (initial-activity group) lost considerably more weight than the delayed-activity group in the first 6 months. Moreover, the type III obese participants in this study lost considerable weight (10.9% at 95% confidence interval) compared to participants with type II obese participants- 7% at 95% confidence interval (Goodpaster, Delany & Otto, 2010, p.1798).
However, the pattern of results that compared both the initial-activity and delayed-activity groups was not affected when both race/ethnicity and obesity type were included in the analysis. In addition, the intervention effects were steady when the outcomes were analyzed on the basis of the baseline observations carried forward. The findings of this research are in concurrence with previous studies that focused on the effects of physical activity on type I obese participants. These studies reported that physical activity considerably stimulates weight loss. The findings of these studies thus support the argument that physical activity plays an integral role in reducing weight among obese people. Nonetheless, the major limitation of the present study was that it assessed the effects of physical activity and dietary intervention among the participants for a limited period. Consequently, the long-term effects of physical activity and dietary interventions were not evaluated. Another salient limitation of the study was that most of the participants were women. In spite of the fact that the groups were randomized in terms of sex, the researchers were not able to establish sex-specific responses. It is against this background that the researchers recommended that future studies should examine the long-term effects of intensive lifestyle intervention on weight loss among people with severe obesity (Goodpaster, Delany & Otto, 2010, p.1798).
The researchers concluded that intensive lifestyle interventions (such as intensive physical activity) can lead to considerable reduction in cardio-metabolic risk factors as well as meaningful and clinically significant weight loss among people with severe obesity. This conclusion is justified by the data collected by the researchers which lend credence to the significance of behavior-based strategy in reducing weight and cardio-metabolic risk factors among people with severe obesity. In addition, healthcare systems can adopt the results of this study by integrating intensive lifestyle interventions as part of the treatment process for people with severe obesity (Goodpaster, Delany & Otto, 2010, p.1798).
References
Flegal, K.M., Carroll, M.D., & Ogden, C.L. (2010). Prevalence and trends in obesity among US adults, 1999-2008. JAMA, 303, 235-241.
Goodpaster, B.H., Delany, J.P., & Otto, A.M. (2010). Effects of Diet and Physical Activity Interventions on Weight Loss and Cardiometabolic Risks Factors in Severely Obese Adults: A Randomized Trial. JAMA, 304, 1795-1802.