We propose a nonparametric Bayesian approach to estimate the natural direct and indirect effects through a mediator in the setting of a continuous mediator and a binary response. Several conditional independence assumptions are introduced (with corresponding sensitivity parameters) to make these effects identifiable from the observed data. We suggest strategies for eliciting sensitivity parameters and conduct simulations to assess violations to the assumptions. This approach is used to assess mediation in a recent weight management clinical trial.
The current study examined racial/ethnic differences in patterns of weight loss and regain in response to an initial behavioral weight loss intervention followed by an extended-care maintenance program.
We analyzed data from 224 women (African-American n = 43, Caucasian n = 181) from rural communities who participated in an initial 6-month lifestyle intervention for obesity and were then randomized to a face-to-face, telephone, or educational/control extended-care condition.
African-American participants lost less weight during the initial phase of treatment than Caucasian participants (mean ± SE = −6.8 ± .80 vs. −10.7 ± .38 kg, respectively, p = .003). Investigating weight change during month 6 to month 18, we found a significant interaction between race/ethnicity and the provision of an extended-care program. Caucasian participants randomized to either of two extended-care programs regained less weight than those assigned to the control condition (1.2 ± .58 and 4.2 ± .79 kg, respectively, p = .003), but the provision of extended care did not influence weight regain among African-American participants (1.9 ± 1.12 and 1.34 ± 2.04 kg, respectively, p = .815).
Collectively, these findings suggest that although African-American participants lost less weight during the initial phase of treatment, they exhibited better long-term weight-loss maintenance than Caucasian participants. Further, while the provision of extended care successfully enhanced weight maintenance among Caucasian participants, African-American participants maintained their initial weight losses regardless of extended care.
Weight Loss; Weight Regain; Race; Racial Difference; Lifestyle Intervention
Rural residents have higher rates of chronic diseases compared to their urban counterparts, and obesity may be a major contributor to this disparity. This study is the first analysis of obesity prevalence in rural and urban adults using body mass index classification with measured height and weight. In addition, demographic, diet, and physical activity correlates of obesity across rural and urban residence are examined.
Analysis of body mass index (BMI), diet, and physical activity from 7,325 urban and 1,490 rural adults in the 2005–2008 National Health and Nutrition Examination Survey (NHANES).
The obesity prevalence was 39.6% (SE = 1.5) among rural adults compared to 33.4% (SE = 1.1) among urban adults (P = .006). Prevalence of obesity remained significantly higher among rural compared to urban adults controlling for demographic, diet, and physical activity variables (odds ratio = 1.18, P = .03). Race/ethnicity and percent kcal from fat were significant correlates of obesity among both rural and urban adults. Being married was associated with obesity only among rural residents, whereas older age, less education, and being inactive was associated with obesity only among urban residents.
Obesity is markedly higher among adults from rural versus urban areas of the United States, with estimates that are much higher than the rates suggested by studies with self-reported data. Obesity deserves greater attention in rural America.
epidemiology; health disparities; obesity; rural; social determinants of health
To compare the costs of parent-only and family-based group interventions for childhood obesity delivered through Cooperative Extension Services in rural communities.
Ninety-three ovenueight or obese children (aged 8 to 14 years) and their parent(s) participated in this randomized controlled trial, which included a 4-month intervention and 6-month follow-up. Families were randomized to either a behavioral family-based intervention (n = 33), a behavioral parent-only intervention (n = 34), or a waitlist control condition (n = 26). Only program costs data for the parent-only and family-based programs are reported here (n = 67). Assessments were completed at baseline, post-treatment (month 4) and follow-up (month 10). The primary outcome measures were total program costs and cost per child for the parent-only and family interventions.
Twenty-six families in the parent-only intervention and 24 families in the family intervention completed all 3 assessments. As reported previously, both intervention programs led to significantly greater decreases in weight status relative to the control condition at month 10 follow-up. There was no significant difference in weight status change between the parent-only and family interventions. Total program costs for the parent-only and family interventions were $13,546 and $20,928, respectively. Total cost per child for the parent-only and family interventions were $521 and $872, respectively.
Parent-only interventions may be a cost-effective alternative treatment for pediatric obesity, especially for families in medically underserved settings.
To assess the effectiveness of parent-only vs family-based interventions for pediatric weight management in underserved rural settings.
A 3-arm randomized controlled clinical trial.
All sessions were conducted at Cooperative Extension Service offices in underserved rural counties.
Ninety-three overweight or obese children (8–14 years old) and their parent(s).
Families were randomized to (1) a behavioral family-based intervention, (2) a behavioral parent-only intervention, or (3) a wait-list control group.
The primary outcome measure was change in children’s standardized body mass index (BMI).
Seventy-one children completed posttreatment (month 4) and follow-up (month 10) assessments. At the month 4 assessment, children in the parent-only intervention demonstrated a greater decrease in BMI z score (mean difference [MD], 0.127; 95% confidence interval [CI], 0.027 to 0.226) than children in the control condition. No significant difference was found between the family-based intervention and the control condition (MD, 0.065; 95% CI, −0.027 to 0.158). At month 10 follow-up, children in the parent-only and family-based intervention groups demonstrated greater decreases in BMI z score from before treatment compared with those in the control group (MD, 0.115; 95% CI, 0.003 to 0.220; and MD, 0.136; 95% CI, 0.018 to 0.254, respectively). No difference was found in weight status change between the parent-only and family-based interventions at either assessment.
A parent-only intervention may be a viable and effective alternative to family-based treatment of childhood overweight. Cooperative Extension Service offices have the potential to serve as effective venues for the dissemination of obesity-related health promotion programs.
Controversy exists regarding the optimal rate of weight loss for long-term weight management success.
This study examined whether gradual initial weight loss was associated with greater long-term weight reduction than rapid initial loss.
Groups were drawn from participants in the TOURS trial, which included a sample of middle-aged (mean =59.3 years) obese women (mean BMI =36.8) who received a 6-month lifestyle intervention followed by a 1-year extended care program. Participants were encouraged to reduce caloric intake to achieve weight losses of 0.45 kg/ week. Groups were categorized as “FAST” (≥0.68 kg/week, n=69), “MODERATE” (≥0.23 and <0.68 kg/week, n= 104), and “SLOW” (<0.23 kg/week, n=89) based on rate of weight loss during first month of treatment.
The FAST, MODERATE, and SLOW groups differed significantly in mean weight changes at 6 months (−13.5, −8.9, and −5.1 kg, respectively, ps <0.001), and the FAST and SLOW groups differed significantly at 18 months (−10.9, −7.1, and −3.7 kg, respectively, ps <0.001). No significant group differences were found in weight regain between 6 and 18 months (2.6, 1.8, and 1.3 kg, respectively, ps < 0.9). The FAST and MODERATE groups were 5.1 and 2.7 times more likely to achieve 10% weight losses at 18 months than the SLOW group.
Collectively, findings indicate both short- and long-term advantages to fast initial weight loss. Fast weight losers obtained greater weight reduction and long-term maintenance, and were not more susceptible to weight regain than gradual weight losers.
Obesity; Weight loss; Lifestyle modification
Rural counties in the U.S. have higher rates of obesity, sedentary lifestyle, and associated chronic diseases than non-rural areas, yet the management of obesity in rural communities has received little attention from researchers.
To compare 2 extended-care programs for weight management with an education control group.
Design, Setting, and Participants
234 obese women from rural communities who completed an initial 6-month weight-loss program were randomized to extended-care, delivered via telephone counseling or face-to-face sessions, or to an education control group. Cooperative Extension Service offices in six medically underserved rural counties served as venues for the trial. The study was conducted from June 2003 to May 2007.
The extended-care programs entailed problem-solving counseling delivered in 26 biweekly sessions. Control group participants received 26 biweekly newsletters containing weight-control advice.
Main Outcome Measure
Change in weight from randomization.
Mean weight at study entry was 96.4 kg. Mean weight loss during the initial 6-month intervention was 10.0 kg. One year after randomization, participants in the telephone and face-to-face conditions regained less weight (means ± SE = 1.3 ± 0.7 and 1.2 ± 0.6 kg, respectively) than those in the education control group (3.7 ± 0.6 kg; Ps = 0.02 and 0.03). The beneficial effects of extended-care counseling were mediated by greater adherence to behavioral weight-management strategies, and cost analyses indicated that telephone counseling was less expensive than face-to-face intervention.
Extended care delivered either by telephone or face-to-face sessions improved the one-year maintenance of lost weight compared to education alone. Telephone counseling constitutes an effective and cost-efficient option for long-term weight management. Delivering lifestyle interventions via the existing infrastructure of the Cooperative Extension Service represents a viable means of research translation into rural communities with limited access to preventive health services.
ClinicalTrials.gov number, NCT00201006.
Few investigations of successful long-term weight loss beyond two years have been conducted, and none has examined weight changes in medically underserved rural populations of older adults. The purpose of this study was to assess long-term weight loss maintenance 3.5 years after the completion of an initial six-month lifestyle intervention for obesity among women aged 50–75 years residing in rural communities.
One hundred and ten obese women with a mean (± standard deviation) age of 60.08 ± 6.17 years and mean body mass index of 36.76 ± 5.10 kg/m2 completed an in-person assessment during which their weight and adherence to behavioral weight management strategies were evaluated.
Participants showed a mean weight reduction of 10.17% ± 5.0% during the initial six- month intervention and regained 6.95% ± 9.44% from the completion of treatment to follow-up assessment 3.5 years later. A substantial proportion of participants (41.80%) were able to maintain weight reductions of 5% or greater from baseline to follow-up. “Successful” participants (those who maintained losses of 5% or greater at follow-up) reported weighing themselves, self-monitoring their intake and calories, planning meals in advance, and choosing lower calorie foods with greater frequency than “unsuccessful” participants (those who lost less than 5%).
Collectively, these findings indicate that a large proportion of participants were able to maintain clinically significant weight losses for multiple years after treatment, and that self-monitoring was a key component of successful long-term weight management.
obesity; weight loss; weight maintenance; lifestyle intervention; rural; health disparities
Obese breast cancer survivors have increased risk of recurrence and death compared to their normal weight counterparts. Rural women have significantly higher obesity rates, thus weight control intervention may be a key strategy for prevention of breast cancer recurrence in this population. This one arm treatment study examined the impact of a group-based weight control intervention delivered through conference call technology to obese breast cancer survivors living in remote rural locations. The intervention included a reduced calorie diet incorporating prepackaged entrees and shakes, physical activity gradually increased to 225 min/week of moderate intensity exercise, and weekly group phone sessions. Outcomes included anthropomorphic, diet, physical activity, serum biomarker, and quality of life changes. Ninety-one percent of participants (31 of 34) attended > 75% of intervention sessions and completed post-treatment data collection visits. At 6 months, significant changes were observed for weight (-12.5 ± 5.8 kg, 13.9% of baseline weight), waist circumference (-9.4 ± 6.3 cm), daily energy intake (-349 ± 550 kcal/day), fruits and vegetables (+3.7 ± 4.3 servings/day), percent kcal from fat (-12.6 ± 8.6%), physical activity (+1235 ± 832 kcal/week; all p’s < .001), as well as significant reductions in fasting insulin (16.7% reduction, p = .006) and leptin (37.1% reduction, p < .001). Significant improvements were also seen for quality of life domains including mood, body image, and sexuality. In conclusion, the intervention produced > 10% weight loss as well as significant improvements across multiple endpoints. The group phone-based treatment delivery approach may help disseminate effective weight control intervention to hard-to-reach breast cancer survivors.
breast cancer; survivors; rural; weight control; physical activity
A key issue in the treatment of obesity in older adults is whether the health benefits of weight loss outweigh the potential risks with respect to musculoskeletal injury.
To compare change in weight, improvements in metabolic risk factors, and reported musculoskeletal adverse events in middle-aged (50–59 years) and older (65–74 years), obese women.
Materials and methods
Participants completed an initial 6-month lifestyle intervention for weight loss, comprised of weekly group sessions, followed by 12 months of extended care with biweekly contacts. Weight and fasting blood samples were assessed at baseline, month 6, and month 18; data regarding adverse events were collected throughout the duration of the study.
Both middle-aged (n = 162) and older (n = 56) women achieved significant weight reductions from baseline to month 6 (10.1 ± 0.68 kg and 9.3 ± 0.76 kg, respectively) and maintained a large proportion of their losses at month 18 (7.6 ± 0.87 kg and 7.6 ± 1.3 kg, respectively); there were no significant differences between the two groups with respect to weight change. Older women further experienced significant reductions in systolic blood pressure, HbA1c, and C-reactive protein from baseline to month 6 and maintained these improvements at month 18. Despite potential safety concerns, we found that older women were no more likely to experience musculoskeletal adverse events during the intervention as compared with their middle-aged counterparts.
These results suggest that older, obese women can experience significant health benefits from lifestyle treatment for obesity, including weight loss and improvements in disease risk factors. Further investigation of the impact of weight loss on additional health-related parameters and risks (eg, body composition, muscular strength, physical functioning, and injuries) in older adults is needed.
lifestyle intervention; adverse events; metabolic risk factors
This study examined whether improvements in problem-solving abilities mediate the relation between treatment adherence and weight-loss outcome in the behavioral treatment of obesity.
272 women (mean ± SD age = 59.4 ± 6.2 years, BMI = 36.5 ± 4.8) participated in a 6-month lifestyle intervention for obesity. Body weight and problem-solving skills (as measured by the Social Problem Solving Inventory—Revised) were assessed pre- and posttreatment. The completion of self-monitoring logs during the intervention served as the marker of treatment adherence.
At posttreatment, participants lost 8.4 ± 5.8 kg, an 8.8% reduction in body weight. Changes in weight were associated with increased problem-solving skills and with higher levels of treatment adherence. Improvements in problem-solving skills partially mediated the relation between treatment adherence and weight-loss outcome. Moreover, participants with weight reductions > 10% demonstrated significantly greater improvements in problem-solving skills than those with reductions < 5%.
Improvements in problem-solving skills may enable participants to overcome barriers to adherence and thereby enhance treatment-induced weight losses.
Obesity; Weight Loss; Problem-Solving; Adherence; Self-Monitoring
The relative contribution of obesity versus poor fitness to adverse health outcomes and diminished quality of life remains an area of controversy. Indeed, some researchers contend that poor cardiorespiratory fitness represents a greater threat to health and health-related quality of life than excess body weight. We addressed this issue by providing 298 obese 50–75 year-old women with a six-month lifestyle intervention that incorporated a low-calorie eating pattern coupled with an aerobic exercise program consisting of 30 min/day of brisk walking. The results showed that weight loss exhibited a significant individual contribution to improvements in seven of the nine domains of quality of life assessed by the Medical Outcomes Study Short Form (SF-36). With the exception of physical functioning, however, physical fitness did not significantly contribute to improvements beyond the effects weight loss. Moreover, weight loss functioned as a full mediator of the association between increases in physical fitness and improvements in general health, vitality, and change in health relative to the previous year. Collectively, these findings suggest that for treatment-seeking obese individuals, weight loss rather than increased fitness contributes significantly to improvements in health-realted quality of life.
Obesity; Health Related Quality of Life; Physical Fitness; Weight Loss
Our goal was to determine whether behavioral economic constructs—including impulsivity (i.e., steep discounting of delayed food and monetary rewards), the relative reinforcing value of food (RRVfood), and environmental enrichment (i.e., the presence of alternatives to unhealthy foods in the home and neighborhood environments)—are significant pretreatment predictors of overweight children’s weight loss within family-based treatment.
Overweight children (N = 241; ages 7–12 years; 63% female; 65% non-Hispanic White) enrolled in a 16-week family-based obesity treatment with at least one parent. At baseline, children completed a task to assess RRVfood and delay discounting measures of snack foods and money to assess impulsivity. Parents completed questionnaires to assess environmental enrichment.
Children who found food highly reinforcing and steeply discounted future food rewards at baseline showed a blunted response to treatment compared with children without this combination of risk factors. High environmental enrichment was associated with treatment success only among children who did not find food highly reinforcing. Monetary discounting rate predicted weight loss, regardless of children’s level of RRVfood.
Investigation is warranted into novel approaches to obesity treatment that target underlying impulsivity and RRVfood. Enriching the environment with alternatives to unhealthy eating may facilitate weight loss, especially for children with low RRVfood.
pediatric obesity treatment; impulsivity; reinforcing value of food; environmental enrichment
Obese older adults are particularly susceptible to sarcopenia and have a higher prevalence of disability than their peers of normal weight. Interventions to improve body composition in late life are crucial to maintaining independence. The main mechanisms underlying sarcopenia have not been determined conclusively, but chronic inflammation, apoptosis, and impaired mitochondrial function are believed to play important roles. It has yet to be determined whether impaired cellular quality control mechanisms contribute to this process. The objective of this study was to assess the effects of a 6-month weight loss program combined with moderate-intensity exercise on the cellular quality control mechanisms autophagy and ubiquitin-proteasome, as well as on inflammation, apoptosis, and mitochondrial function, in the skeletal muscle of older obese women. The intervention resulted in significant weight loss (8.0 ± 3.9 % vs. 0.4 ± 3.1% of baseline weight, p = 0.002) and improvements in walking speed (reduced time to walk 400 meters, − 20.4 ± 16% vs. − 2.5 ± 12%, p = 0.03). In the intervention group, we observed a three-fold increase in messenger RNA (mRNA) levels of the autophagy regulators LC3B, Atg7, and lysosome-associated membrane protein-2 (LAMP-2) compared to controls. Changes in mRNA levels of FoxO3A and its targets MuRF1, MAFBx, and BNIP3 were on average seven-fold higher in the intervention group compared to controls, but these differences were not statistically significant. Tumor necrosis factor-α (TNF-α) mRNA levels were elevated after the intervention, but we did not detect significant changes in the downstream apoptosis markers caspase 8 and 3. Mitochondrial biogenesis markers (PGC1α and TFAm) were increased by the intervention, but this was not accompanied by significant changes in mitochondrial complex content and activity. In conclusion, although exploratory in nature, this study is among the first to report the stimulation of cellular quality control mechanisms elicited by a weight loss and exercise program in older obese women.
The Extension Family Lifestyle Intervention Project (E-FLIP for Kids) is a three-arm, randomized controlled trial assessing the effectiveness of two behavioral weight management interventions in an important and at-risk population, overweight and obese children and their parents in rural counties.
Participants will include 240 parent-child dyads from nine rural counties in north central Florida. Dyads will be randomized to one of three conditions: (a) a Family-Based Behavioral Group Intervention, (b) a Parent-Only Behavioral Group Intervention, and (c) an Education Control Condition. Child and parent participants will be assessed at baseline (month 0), post-treatment (month 12) and follow-up (month 24). Assessment and intervention sessions will be held at Cooperative Extension Service offices within each participating county. The primary outcome measure is change in child BMI z-score. Additional key outcome measures include child body fat, waist circumference, dietary intake, physical activity, blood lipids, blood glucose, blood pressure, physical fitness, quality of life, and program and participants costs. Parent BMI, dietary intake, and physical activity also will be assessed.
Randomized controlled trials testing the effectiveness of childhood obesity interventions in real-world community-based settings are extremely valuable, but much too rare. The E-FLIP for Kids trial will evaluate the impact of a community based intervention delivered to families in rural settings utilizing the existing Cooperative Extension Service network on long-term child behavior, weight status and biological markers of diabetes and early cardiovascular disease. If successful, a Parent-Only intervention program may provide a cost-effective and practical intervention for families in underserved rural communities.
Obesity; Children; Behavioral Intervention; Treatment; Randomized Controlled Trial
A primary focus of longevity research is to identify prognostic risk factors that can be mediated by early treatment efforts. To date, much of this work has focused on understanding the biological processes that may contribute to aging process and age-related disease conditions. Although such processes are undoubtedly important, no current biological intervention aimed at increasing health and lifespan exists. Interestingly, a close relationship between mobility performance and the aging process has been documented in older adults. For example, recent studies have identified functional status, as assessed by walking speed, as a strong predictor of major health outcomes, including mortality, in older adults. This paper aims to describe the relationship between the comorbidities related to decreased health and lifespan and mobility function in obese, older adults. Concurrently, lifestyle interventions, including diet and exercise, are described as a means to improve mobility function and thereby limit the functional limitations associated with increased mortality.
Obesity and a sedentary lifestyle are associated with physical impairments and biologic changes in older adults. Weight loss combined with exercise may reduce inflammation and improve physical functioning in overweight, sedentary, older adults. This study tested whether a weight loss program combined with moderate exercise could improve physical function in obese, older adult women.
Participants (N = 34) were generally healthy, obese, older adult women (age range 55–79 years) with mild to moderate physical impairments (ie, functional limitations). Participants were randomly assigned to one of two groups for 24 weeks: (i) weight loss plus exercise (WL+E; n = 17; mean age = 63.7 years [4.5]) or (ii) educational control (n = 17; mean age = 63.7 [6.7]). In the WL+E group, participants attended a group-based weight management session plus three supervised exercise sessions within their community each week. During exercise sessions, participants engaged in brisk walking and lower-body resistance training of moderate intensity. Participants in the educational control group attended monthly health education lectures on topics relevant to older adults. Outcomes were: (i) body weight, (ii) walking speed (assessed by 400-meter walk test), (iii) the Short Physical Performance Battery (SPPB), and (iv) knee extension isokinetic strength.
Participants randomized to the WL+E group lost significantly more weight than participants in the educational control group (5.95 [0.992] vs 0.23 [0.99] kg; P < 0.01). Additionally, the walking speed of participants in the WL+E group significantly increased compared with that of the control group (reduction in time on the 400-meter walk test = 44 seconds; P < 0.05). Scores on the SPPB improved in both the intervention and educational control groups from pre- to post-test (P < 0.05), with significant differences between groups (P = 0.02). Knee extension strength was maintained in both groups.
Our findings suggest that a lifestyle-based weight loss program consisting of moderate caloric restriction plus moderate exercise can produce significant weight loss and improve physical function while maintaining muscle strength in obese, older adult women with mild to moderate physical impairments.
obesity; weight loss; physical function; oxidative stress; inflammation; walking speed
Weight loss outcomes achieved through conventional behavior change interventions are prone to deterioration over time. Basic learning laboratory studies in the area of behavioral extinction and renewal and multi-level models of weight control offer clues as to why newly acquired weight loss skills are prone to relapse. According to these models, current clinic-based interventions may not be of sufficient duration or scope to allow for the practice of new skills across the multiple community contexts necessary to promote sustainable weight loss. Although longer, more intensive interventions with greater reach may hold the key to improving weight loss outcomes, it is difficult to test these assumptions in a time efficient and cost-effective manner. A research design tool that has been increasingly utilized in other fields (e.g., pharmaceuticals) is the use of biosimulation analyses. The present paper describes our research team's use of computer simulation models to assist in designing a study to test a novel, comprehensive socio-environmental treatment approach to weight loss maintenance in children ages 7 to 12 years.
Weight outcome data from the weight loss, weight maintenance, and follow-up phases of a recently completed randomized controlled trial (RCT) were used to describe the time course of a proposed, extended multi-level treatment program. Simulations were then conducted to project the expected changes in child percent overweight trajectories in the proposed study.
A 12.9% decrease in percent overweight at 30 months was estimated based upon the midway point between models of “best-case” and “worst-case” weight maintenance scenarios.
Preliminary data and further analyses, including biosimulation projections, suggest that our socio-environmental approach to weight loss maintenance treatment is promising and warrants evaluation in a large-scale RCT. Biosimulation techniques may have utility in the design of future community-level interventions for the treatment and prevention of childhood overweight.
Rural women have among the highest rates of obesity and sedentary lifestyle, yet few studies have examined strategies for delivering state-of-the-art obesity treatment to hard-to-reach rural areas. The purpose of this pilot trial was to examine the impact and cost-effectiveness of a 6-month behavioral weight loss program delivered to rural women by phone either one-on-one with a counselor or to a group via conference call. Thirty-four rural women (mean BMI=34.4, SD=4.6) were randomized to group phone-based treatment or individual phone-based treatment. Completers analysis showed that weight loss was greater in the group condition (mean=14.9 kg=, SD=4.4) compared to the individual condition (mean=9.5 kg, SD=5.2; p=.03). Among the total sample, 62% of participants in the group condition achieved the 10% weight loss goal compared to 50% in the individual condition, and group treatment was found to be more cost-effective. Future research is warranted to examine the benefits of group phone-based treatment for long-term management of obesity among rural populations.
obesity treatment; rural; phone counseling; group treatment
Project STORY is a 3-arm, randomized, planning and feasibility study assessing the effectiveness of two behavioral weight management interventions in an important and at-risk population, overweight children and their parents in medically underserved rural counties.
Participants will include 90 parent-child dyads from rural counties in north central Florida. Families will be randomized to one of three conditions: (a) a Family-Based Behavioral Group Intervention, (b) a Parent-Only Behavioral Group Intervention, and (c) a waitlist control condition. Child and parent participants will be assessed at baseline (month 0), post-treatment (month 4) and follow-up (month 10). Assessment and intervention sessions will be held at Cooperative Extension offices within each local participating county. The primary outcome measure is change in child body mass index (BMI) z-score. Additional key outcome measures include child dietary intake, physical activity, self-esteem, body image, and parent BMI.
The goals of the study are to (a) assess the feasibility of recruitment in rural settings, (b) develop and evaluate training protocol for group leaders, (c) determine strategies to increase adherence to monitoring and goal setting protocol, (d) evaluate strategies for participant retention, (e) assess the relative cost-effectiveness of the interventions, (f) assess the acceptability of the intervention to families and Cooperative Extension administrators and personnel, and (g) if successful, estimate the sample size needed for a full scale trial. This research has potential implications for medically underserved rural communities with limited resources and preventive health care services. If successful, a Parent-Only intervention program may provide a cost-effective and practical intervention for families in underserved rural communities.
Obesity; Children; Behavioral Intervention; Treatment; Randomized Controlled Trial
A major challenge following successful weight loss is continuing the behaviors required for long-term weight maintenance. This challenge may be exacerbated in rural areas with limited local support resources.
This study describes and compares program costs and cost-effectiveness for 12-month extended care lifestyle maintenance programs following an initial 6-month weight loss program.
A 1-year prospective controlled randomized clinical trial.
The study included 215 female participants age 50 or older from rural areas who completed an initial 6-month lifestyle program for weight loss. The study was conducted from June 1, 2003, to May 31, 2007.
The intervention was delivered through local Cooperative Extension Service offices in rural Florida. Participants were randomly-assigned to a 12-month extended care program using either individual telephone counseling (n=67), group face-to-face counseling (n=74), or a mail/control group (n=74).
Main Outcome Measures
Program delivery costs, weight loss, and self-reported health status were directly assessed through questionnaires and program activity logs. Costs were estimated across a range of enrollment sizes to allow inferences beyond the study sample.
Statistical Analyses Performed
Non-parametric and parametric tests of differences across groups for program outcomes were combined with direct program cost estimates and expected value calculations to determine which scales of operation favored alternative formats for lifestyle maintenance.
Median weight regain during the intervention year was 1.7 kg for participants in the face-to-face format, 2.1 kg for the telephone format, and 3.1 kg for the mail/control format. For a typical group size of 13 participants, the face-to-face format had higher fixed costs, which translated into higher overall program costs ($420 per participant) when compared to individual telephone counseling ($268 per participant) and control ($226 per participant) programs. While the net weight lost after the 12-month maintenance program was higher for the face-to-face and telephone programs compared to the control group, the average cost per expected kilogram of weight lost was higher for the face-to-face program ($47/kg) compared to the other two programs (approximately $33/kg for telephone and control).
Both the scale of operations and local demand for programs are important considerations in selecting a delivery format for lifestyle maintenance. In this study, the telephone format had a lower cost, but similar outcomes compared to the face-to-face format.
Obesity; cost-effectiveness; randomized trial; rural health