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Two-year outcomes of an adjunctive telephone coaching and electronic contact intervention for adolescent weight-loss maintenance: the Loozit randomized controlled trial

Abstract

This paper reports the final 24-month outcomes of a randomized controlled trial evaluating the effect of additional therapeutic contact (ATC) as an adjunct to a community-based weight-management program for overweight and obese 13–16-year-olds. ATC involved telephone coaching or short-message-service and/or email communication once per fortnight. Adolescents were randomized to receive the Loozit group program—a two-phase behavioral lifestyle intervention with (n=73), or without (n=78), ATC in Phase 2. Adolescents/parents separately attended seven weekly group sessions (Phase 1), followed by quarterly adolescent sessions (Phase 2). Assessor-blinded, 24-month changes in anthropometry and metabolic health included primary outcomes body mass index (BMI) z-score and waist:height ratio (WHtR). Secondary outcomes were self-reported psychosocial and lifestyle changes. By 24 months, 17 adolescents had formally withdrawn. Relative to the Loozit program alone, ATC largely had no impact on outcomes. Secondary pre-post assessment of the Loozit group program showed mean (95% CI) reductions in BMI z-score (−0.13 (−0.20, −0.06)) and WHtR (−0.02 (−0.03, −0.01)) in both arms, with several metabolic and psychosocial improvements. Adjunctive ATC did not provide further benefits to the Loozit group program. We recommend that further work is needed to optimize technological support for adolescents in weight-loss maintenance. Australian New Zealand Clinical Trials Registry Number ACTRNO12606000175572.

Introduction

There are limited high-quality data on long-term outcomes of adolescent obesity treatment, particularly low-intensity community-based programs that could be sustainably delivered in typical healthcare systems.1 The Loozit group program is a 24-month behavioral lifestyle intervention specifically designed to treat overweight and obese 13–16-year-olds in community settings. The program involves seven weekly group sessions (Phase 1) for adolescents and parents, followed by quarterly adolescent booster group sessions for weight-loss maintenance (Phase 2) between 2–24 months. The randomized controlled trial (RCT) component, and novel aspect of this study, was the evaluation of adjunctive additional therapeutic contact (ATC) provided fortnightly to adolescents in one arm of the study, via telephone coaching, short message service (SMS) and/or email communication, in Phase 2. There are few, if any, community-based adolescent weight-management RCTs that have such a long weight-loss maintenance intervention or involve interactive electronic contact.1

We have previously reported that Loozit group program participants had a stabilization in overweight after 2 months,2 with greater reductions in overweight by 12 months (mean (95% CI) change in body mass index (BMI) z-score (−0.09 (−0.12, −0.06)).3 At both 2 and 12 months, there were also improvements in most psychological outcomes, various metabolic outcomes, and lifestyle behaviors.2, 3 However, at 12 months, ATC largely had no impact on outcome measures. The primary aim of this paper was to evaluate the effectiveness of ATC provided as an adjunct to this extended weight-loss maintenance intervention, by reporting its impact on the final outcomes at 24 months. A secondary aim was to report pre post outcomes of the Loozit group program.

Materials and methods

Study design

Methods used in this paper replicate those in the 12-month outcomes paper3 with further details published in the protocol.4 Recruitment occurred from 2006 to 2009 mainly via media and schools.5 Eligible participants were overweight and obese (BMI z-score: 1.0–2.5), but otherwise healthy, 13–16-year-olds, who could attend group sessions with a parent/carer, and had landline telephone and mobile phone and/or email access. Randomization to the Loozit group program (‘G’-only) or group program plus ATC (‘G+ATC’), was stratified by sex, age and intervention site, and occurred after informed written consent was provided. This study is registered with the Australian New Zealand Clinical Trials Registry (ACTRNO12606000175572) and was approved by Human Research Ethics Committees of The Children′s Hospital at Westmead (CHW), Sydney West Local Health District, and the University of Sydney.

Intervention

The Loozit group behavioral lifestyle intervention was conducted at a community health center and CHW, Sydney, Australia, commencing with 7 × 75-min weekly group sessions (Phase 1), held separately for adolescents and parents/carers in both study arms. From 2–24 months (Phase 2), the maintenance program involved 5 × 60-min quarterly adolescent booster group sessions plus 12- and 24-month outcome assessment sessions. Facilitated by trained dietitians, group sessions were based upon a cognitive behavioral approach,6 and recommendations were consistent with clinical practice guidelines.7 In Phase 2, ‘G+ATC’ adolescents were scheduled to receive ATC fortnightly (overall 14 telephone coaching sessions and 32 SMS and/or email messages).

Measures

Primary outcomes were baseline to 24-month changes in BMI z-score8 and waist:height ratio (WHtR). Secondary outcomes included changes in other anthropometric and metabolic measures (Table 1) and self-reported psychosocial and behavioral variables. Psychosocial well-being was assessed using the Mental Health Inventory-5,9 sex-specific body dissatisfaction scales,10 the MacArthur Scale of Subjective Social Status11 and the Harter Self Perception Profile for Adolescents.12 A 15-item food-frequency questionnaire13 and eating behavior questions14 assessed dietary intake. The Children′s Leisure Activities Study Survey measured physical activity and sedentary behaviors.15 Adolescents and parents anonymously completed program satisfaction questionnaires. Intervention participation and reported adverse events were recorded.

Table 1 Anthropometric and metabolic outcomes by treatment group and time over 24 months

Statistical analyses

Data were analyzed using SPSS, v.19 (SPSS Inc., Chicago, IL, USA) with statistical significance accepted as P<0.05. Non-normally distributed variables were log-transformed for analysis and are presented as back-transformed data. Linear mixed models were used for all outcomes except dietary variables that were dichotomized and analyzed with generalized estimating equation models with a binomial distribution. Models used an intention-to-treat approach with an unstructured covariance structure to test for time (as repeated factor with levels: baseline, 2, 12 and 24 months) and group effects. Group-by-time interactions were included if fixed effects were significant. The least significant difference method was used for post hoc comparisons. Base models were adjusted for additional significant effects of sex and baseline age.

Results

Participants

Figure 1 presents participation from recruitment to 24 months. Of 151 randomized adolescents, 9% did not receive any intervention, and, by 24 months, a further 11% had formally withdrawn. Twenty-four-month anthropometry/BP and metabolic outcomes were assessed in 62% and 47% of adolescents, respectively. Baseline anthropometry/BP and demographic characteristics were not different between adolescents who formally withdrew and those who did not, or adolescents with and without 24-month follow-up. Booster session attendance declined from 69% to 31% between the first and final session. The median (range) number of telephone coaching sessions received and SMS/email messages sent, respectively, was 12 (2 to 15) and 31 (14 to 33). Of 93 adolescents and 79 parents who completed satisfaction questionnaires, respectively, 87% and 97%, responded they would recommend the Loozit program to others. Adverse events throughout the study included parent-reported disordered eating (n=3) and poor body image (n=2), prescription drug overdose (n=1) and a fractured ankle (n=1).

Figure 1
figure1

RCT participation from recruitment to 24 months.

Effect of ATC

There were no statistically significant group effects or group-by-time interactions indicating an effect of ATC for primary outcomes, and very few for secondary outcomes at 24 months (Table 1). Compared with the G-only group at each time point, the G+ATC group had a higher systolic BP (mean (95% CI) group difference: 3 mm Hg (0,6)), only after adjusting for sex and baseline age, and lower perceived athletic competence (−0.22 (−0.44, 0.00)). Accounting for significant group-by-time interactions did not change 24-month outcomes except for the greater amount of time spent using the computer in the G+ATC group at 24 months (2.3 h (1.0, 4.9)).

Pre-post assessment of the Loozit program

Anthropometry and metabolic health

Table 1 presents anthropometric and metabolic outcomes by group and time. Time effects, that is, baseline to 24-month changes, for both arms combined are reported herein. At 24 months, there were statistically significant reductions in BMI z-score, WHtR, total cholesterol, HDL cholesterol and triglycerides, and increases in systolic and diastolic BP. Adjusting for sex and baseline age had no effect except the aforementioned group-by-time interaction for systolic BP.

Psychosocial well-being and lifestyle behaviors

Improvements were seen in: body shape satisfaction (mean: 0.43 (95% CI: 0.20, 0.65)), subjective social status (1.26 (0.86, 1.66)), and except for close friendship, all Harter self-perception measures including global self-worth (0.20 (0.09, 0.32)). Participants were more likely to report less frequent consumption of high-fat meat products (odds ratio: 0.22 (95% CI: 0.14, 0.36)), lunch every day (0.49 (0.30, 0.82)) and more likely to report never/rarely consuming fruit juice (2.47 (1.59, 3.82)). Light-intensity physical activity reduced (mean: −0.80 h (95% CI: −0.96, −0.64)) and total leisure activities increased (1.2 h (1.0, 1.4)) including non-screen-based activities (1.4 h (1.1, 1.7)). Adjusting for sex and baseline age had no effect on these outcomes.

Discussion

To our knowledge, this is the first community-based RCT in adolescents investigating the potential impact of telephone coaching combined with electronic communications on long-term weight-management outcomes. As found at 12 months,3 the ATC intervention did not have a significant impact on outcomes at 24 months or attendance at Phase 2 booster sessions. This finding is surprising given the promising application of youth-friendly, electronic technologies in weight-management interventions,16 and as a tool for behavior change.17 It is possible that ATC provided once per fortnight in this RCT did not meet the threshold for change. Daily SMS communications have since been found acceptable to adolescents receiving obesity treatment18, 19 but weight outcomes were not evaluated.

The Loozit group program 24-month outcomes were similar to those at 12 months.3 Between 12 and 24 months, adolescent overweight (BMI z-score) reduced and previous reductions in abdominal adiposity (WHtR) were sustained, despite the generally poor long-term attendance at booster group sessions. Consistent findings included reductions in total cholesterol, triglycerides, consumption of high-fat meat products and lunch, and improvements in most psychosocial outcomes. New findings at 24 months included increases in total and non-screen-based leisure activities and BP (within normal range), and reductions in HDL cholesterol and light physical activity. However, these results reflect the expected secular increases in BP20 and sedentary behaviors,21 and decreases in lunch intake21 and physical activity.21

Absence of a ‘no treatment’ control group somewhat limits interpretation of the group program′s effectiveness but including one would not have been ethical, given the intervention duration. Another limitation was the increasing proportion of missing outcome data (Figure 1), despite persistence in re-scheduling missed measurement sessions.

The 24-month, Loozit group program has proved feasible to deliver in a community setting with modest resources. However, ATC provided no additional therapeutic benefit as a maintenance adjunct to the Loozit program. These results highlight how challenging long-term work with obese adolescents can be and the need to identify strategies for further optimizing weight-management outcomes and treatment engagement. We recommend that future trials evaluate the health outcomes of adjunctive ATC delivered at least once a week, and utilizing existing and emerging youth-friendly technologies.

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Acknowledgements

The Loozit RCT was funded by a University of Sydney Research & Development Grant (2006); a bequest of the Estate of the late RT Hall (2006–08); Macquarie Bank Foundation (2006–08); Financial Markets Foundation for Children (2007–08); and the Heart Foundation of Australia Grant-in-Aid (2009–10). VAS was supported by an Australian National Health and Medical Research Council Biomedical Postgraduate Scholarship (#505009). The funding bodies did not have any input into the design and conduct of the study; the collection, management, analysis, and interpretation of the data; and the preparation, review or approval of this manuscript. We would like to thank the participating adolescents and their parents/carers, as well as The Children′s Hospital at Westmead (CHW) Public Relations Department and local schools for assisting with recruitment. We thank Dr Jennifer Peat and Dr Federica Barzi of the Clinical Epidemiology Unit, CHW, for providing statistical advice. We would also like to thank Anthea Lee, Kate Stevenson, Kristy McGregor, Michele Casey, Susie Burrell, Kerryn Chisholm, Genevieve Dwyer, and Jessica Finlay for their contributions to the study.

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Correspondence to B Nguyen.

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Nguyen, B., Shrewsbury, V., O'Connor, J. et al. Two-year outcomes of an adjunctive telephone coaching and electronic contact intervention for adolescent weight-loss maintenance: the Loozit randomized controlled trial. Int J Obes 37, 468–472 (2013). https://doi.org/10.1038/ijo.2012.74

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Keywords

  • adolescent
  • randomized controlled trial
  • weight loss
  • weight maintenance
  • group therapy
  • cellular phone

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