Browsing by Author "Dutton, Gareth R."

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    A randomized trial comparing weight loss treatment delivered in large versus small groups
    (Springer Nature, 2014-09-24) Dutton, Gareth R.; Nackers, Lisa M.; Dubyak, Pamela J.; Rushing, Nicole C.; Huynh, Tuong-Vi T.; Tan, Fei; Anton, Stephen D.; Perri, Michael G.; Mathematical Sciences, School of Science
    Background: Behavioral interventions for obesity are commonly delivered in groups, although the effect of group size on weight loss has not been empirically evaluated. This behavioral weight loss trial compared the 6- and 12-month weight changes associated with interventions delivered in a large group (LG) or small groups (SG). Methods: Obese adults (N = 66; mean age = 50 years; mean BMI = 36.5 kg/m2; 47% African American; 86% women) recruited from a health maintenance organization were randomly assigned to: (1) LG treatment (30 members/group), or (2) SG treatment (12 members/group). Conditions were comparable in frequency and duration of treatment, which included 24 weekly group sessions (months 1-6) followed by six monthly extended care contacts (months 7-12). A mixed effects model with unstructured covariance matrix was applied to analyze the primary outcome of weight change while accounting for baseline weight and dependence among participants' measurements over time. Results: SG participants lost significantly more weight than LG participants at Month 6 (-6.5 vs. -3.2 kg; p = 0.03) and Month 12 (-7.0 vs. -1.7 kg; p < 0.002). SG participants reported better treatment engagement and self-monitoring adherence at Months 6 and 12, ps < 0.04, with adherence fully mediating the relationship between group size and weight loss. Conclusions: Receiving obesity treatment in smaller groups may promote greater weight loss and weight loss maintenance. This effect may be due to improved adherence facilitated by SG interactions. These novel findings suggest that the perceived efficiency of delivering behavioral weight loss treatment to LGs should be balanced against the potentially better outcomes achieved by a SG approach.
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    Comparison of an alternative schedule of extended care contacts to a self-directed control: a randomized trial of weight loss maintenance
    (BMC, 2017-08-15) Dutton, Gareth R.; Gowey, Marissa A.; Tan, Fei; Zhou, Dali; Ard, Jamy; Perri, Michael G.; Lewis, Cora E.; Mathematical Sciences, School of Science
    Background Behavioral interventions for obesity produce clinically meaningful weight loss, but weight regain following treatment is common. Extended care programs attenuate weight regain and improve weight loss maintenance. However, less is known about the most effective ways to deliver extended care, including contact schedules. Methods We compared the 12-month weight regain of an extended care program utilizing a non-conventional, clustered campaign treatment schedule and a self-directed program among individuals who previously achieved ≥5% weight reductions. Participants (N = 108; mean age = 51.6 years; mean weight = 92.6 kg; 52% African American; 95% female) who achieved ≥5% weight loss during an initial 16-week behavioral obesity treatment were randomized into a 2-arm, 12-month extended care trial. A clustered campaign condition included 12 group-based visits delivered in three, 4-week clusters. A self-directed condition included provision of the same printed intervention materials but no additional treatment visits. The study was conducted in a U.S. academic medical center from 2011 to 2015. Results Prior to randomization, participants lost an average of −7.55 ± 3.04 kg. Participants randomized to the 12-month clustered campaign program regained significantly less weight (0.35 ± 4.62 kg) than self-directed participants (2.40 ± 3.99 kg), which represented a significant between-group difference of 2.28 kg (p = 0.0154) after covariate adjustments. This corresponded to maintaining 87% and 64% of lost weight in the clustered campaign and self-directed conditions, respectively, which was a significant between-group difference of 29% maintenance of lost weight after covariate adjustments, p = 0.0396. Conclusions In this initial test of a clustered campaign treatment schedule, this novel approach effectively promoted 12-month maintenance of lost weight. Future trials should directly compare the clustered campaigns with conventional (e.g., monthly) extended care schedules. Trial registration Clinicaltrials.gov NCT02487121. Registered 06/26/2015 (retrospectively registered)
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    Pre-Treatment and During-Treatment Weight Trajectories in Black and White Women
    (Elsevier, 2022) Schneider-Worthington, Camille R.; Kinsey, Amber W.; Tan, Fei; Zhang, Sheng; Borgatti, Alena; Davis, Andrea; Dutton, Gareth R.; Mathematical Sciences, School of Science
    Introduction: Black participants often lose less weight than White participants in response to behavioral weight-loss interventions. Many participants experience significant pretreatment weight fluctuations (between baseline measurement and treatment initiation), which have been associated with treatment outcomes. Pretreatment weight gain has been shown to be more prevalent among Black participants and may contribute to racial differences in treatment responses. The purpose of this study was to (1) examine the associations between pretreatment weight change and treatment outcomes and (2) examine racial differences in pretreatment weight change and weight loss among Black and White participants. Methods: Participants were Black and White women (n=153, 60% Black) enrolled in a 4-month weight loss program. Weight changes occurring during the pretreatment period (41 ± 14 days) were categorized as weight stable (±1.15% of baseline weight), weight gain (≥+1.15%), or weight loss (≤-1.15%). Recruitment and data collection occurred from 2011 to 2015; statistical analyses were performed in 2021. Results: During the pretreatment period, most participants (56%) remained weight stable. Pretreatment weight trajectories did not differ by race (p=0.481). At 4-months, those who lost weight before treatment experienced 2.63% greater weight loss than those who were weight stable (p<0.005), whereas those who gained weight before treatment experienced 1.91% less weight loss (p<0.01). Conclusions: Pretreatment weight changes can impact weight outcomes after initial treatment, although no differences between Black and White participants were observed. Future studies should consider the influence of pretreatment weight change on long-term outcomes (e.g., weight loss maintenance) along with potential racial differences in these associations.
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    Similar weight loss and maintenance in African American and White women in the Improving Weight Loss (ImWeL) trial
    (Taylor & Francis, 2021) Kinsey, Amber W.; Gowey, Marissa A.; Tan, Fei; Zhou, Dali; Ard, Jamy; Affuso, Olivia; Dutton, Gareth R.; Mathematical Sciences, School of Science
    Objective: African Americans (AA) are often underrepresented and tend to lose less weight than White participants during the intensive phase of behavioral obesity treatment. Some evidence suggests that AA women experience better maintenance of lost weight than White women, however, additional research on the efficacy of extended care programs (i.e. continued contacts to support the maintenance of lost weight) is necessary to better understand these differences. Methods: The influence of race on initial weight loss, the likelihood of achieving ≥5% weight reduction (i.e. extended care eligibility), the maintenance of lost weight and extended care program efficacy was examined in 269 AA and White women (62.1% AA) participating in a 16-month group-based weight management program. Participants achieving ≥5% weight reduction during the intensive phase (16 weekly sessions) were randomized to a clustered campaign extended care program (12 sessions delivered in three, 4-week clusters) or self-directed control. Results: In adjusted models, race was not associated with initial weight loss (p = 0.22) or the likelihood of achieving extended care eligibility (odds ratio 0.64, 95% CI [0.29, 1.38]). AA and White women lost −7.13 ± 0.39 kg and −7.62 ± 0.43 kg, respectively, during initial treatment. There were no significant differences in weight regain between AA and White women (p = 0.64) after adjusting for covariates. Clustered campaign program participants (AA: −6.74 ± 0.99 kg, White: −6.89 ± 1.10 kg) regained less weight than control (AA: −5.15 ± 0.99 kg, White: −4.37 ± 1.04 kg), equating to a 2.12 kg (p = 0.03) between-group difference after covariate adjustments. Conclusions: Weight changes and extended care eligibility were comparable among all participants. The clustered campaign program was efficacious for AA and White women. The high representation and retention of AA participants may have contributed to these findings.