A randomized trial comparing weight loss treatment delivered in large versus small groups

International Journal of Behavioral Nutrition and Physical Activity

Michael G Perri¹  Stephen D Anton²  Fei Tan⁵  Tuong-Vi T Huynh³  Nicole C Rushing⁴  Pamela J Dubyak¹  Lisa M Nackers¹  Gareth R Dutton³ 

[1] Department of Clinical and Health Psychology, University of Florida, Gainesville, FL, USA;Department of Aging and Geriatric Research, University of Florida, Gainesville, FL, USA;Division of Preventive Medicine, University of Alabama at Birmingham, 1717 11th Avenue South, Medical Towers 615, Birmingham 35205, AL, USA;Department of Psychology, Florida State University, Tallahassee, FL, USA;Department of Mathematical Sciences, Indiana University-Purdue University Indianapolis, Indianapolis, IN, USA

关键词: Randomized trial;    Lifestyle intervention;    Group size;    Weight loss;   

Others  :  1136191
DOI  :  10.1186/s12966-014-0123-y

 received in 2014-05-01, accepted in 2014-09-19,  发布年份 2014

【 摘 要 】

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.

【 授权许可】

   
2014 Dutton et al.; licensee BioMed Central Ltd.

【 图 表 】

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