Focusing on fidelity: narrative review and recommendations for improving intervention fidelity within trials of health behaviour change interventions.

Background: Interventions to change behaviour have substantial potential to impact positively on individual and overall public health. Despite an increasing focus on health behaviour change intervention research, interventions do not always have the desired effect on outcomes, while others have diluted effects once implemented into real-life settings. There is little investment into understanding how or why such interventions work or do not work. Methodological inadequacies of trials of behavioural interventions have been previously suggested as a barrier to the quality and advancement of behavioural research, with intervention fidelity acknowledged as a key area for improvement. However, there is much ambiguity regarding the terminology and conceptualisation of intervention fidelity and a lack of practical guidance regarding how to address it sufficiently, particularly within trials of complex behavioural interventions. Objectives: This article outlines specific issues concerning intervention fidelity within trials of health behaviour change interventions and suggests practical considerations and specific recommendations for researchers, with examples from the literature presented. Conclusions: Recommendations pertain to (1) clarifying how fidelity is defined and conceptualised, (2) considering fidelity beyond intervention delivery, (3) considering strategies to both enhance and assess fidelity, (4) making use of existing frameworks and guidance, (5) considering the quality and comprehensiveness of fidelity assessment strategies, (6) considering the balance between fidelity and adaptation and (7) reporting the use of fidelity enhancement and assessment strategies and their results. Suggestions for future research to improve our understanding of, and ability to, address fidelity in behaviour change interventions are also provided.

A systematic review of school-based interventions targeting physical activity and sedentary behaviour among older adolescents.

Lack of physical activity (PA) and high levels of sedentary behaviour (SB) have been associated with health problems. This systematic review evaluates the effectiveness of school-based interventions to increase PA and decrease SB among 15-19-year-old adolescents, and examines whether intervention characteristics (intervention length, delivery mode and intervention provider) and intervention content (i.e. behaviour change techniques, BCTs) are related to intervention effectiveness. A systematic search of randomised or cluster randomised controlled trials with outcome measures of PA and/or SB rendered 10 results. Risk of bias was assessed using the Cochrane risk of bias tool. Intervention content was coded using Behaviour Change Technique Taxonomy v1. Seven out of 10 studies reported significant increases in PA. Effects were generally small and short-term (Cohen's d ranged from 0.132 to 0.659). Two out of four studies that measured SB reported significant reductions in SB. Interventions that increased PA included a higher number of BCTs, specific BCTs (e.g., goal setting, action planning and self-monitoring), and were delivered by research staff. Intervention length and mode of delivery were unrelated to effectiveness. More studies are needed that evaluate long-term intervention effectiveness and target SBs among older adolescents.

A European evidence-based guideline for the prevention of type 2 diabetes.

BACKGROUND: The prevalence and socioeconomic burden of type 2 diabetes (T2DM) and associated co-morbidities are rising worldwide. AIMS: This guideline provides evidence-based recommendations for preventing T2DM. METHODS: A European multidisciplinary consortium systematically reviewed the evidence on the effectiveness of screening and interventions for T2DM prevention using SIGN criteria. RESULTS: Obesity and sedentary lifestyle are the main modifiable risk factors. Age and ethnicity are non-modifiable risk factors. Case-finding should follow a step-wise procedure using risk questionnaires and oral glucose tolerance testing. Persons with impaired glucose tolerance and/or fasting glucose are at high-risk and should be prioritized for intensive intervention. Interventions supporting lifestyle changes delay the onset of T2DM in high-risk adults (number-needed-to-treat: 6.4 over 1.8-4.6 years). These should be supported by inter-sectoral strategies that create health promoting environments. Sustained body weight reduction by >or= 5 % lowers risk. Currently metformin, acarbose and orlistat can be considered as second-line prevention options. The population approach should use organized measures to raise awareness and change lifestyle with specific approaches for adolescents, minorities and disadvantaged people. Interventions promoting lifestyle changes are more effective if they target both diet and physical activity, mobilize social support, involve the planned use of established behaviour change techniques, and provide frequent contacts. Cost-effectiveness analysis should take a societal perspective. CONCLUSIONS: Prevention using lifestyle modifications in high-risk individuals is cost-effective and should be embedded in evaluated models of care. Effective prevention plans are predicated upon sustained government initiatives comprising advocacy, community support, fiscal and legislative changes, private sector engagement and continuous media communication.

Family involvement in weight control, weight maintenance and weight-loss interventions: a systematic review of randomised trials.

OBJECTIVE: To conduct a descriptive systematic review into the nature and effectiveness of family involvement in weight control, weight maintenance and weight-loss interventions. METHOD: We searched Medline and Psyclit for English language papers describing randomised trials with at least 1-y follow-up that evaluated interventions incorporating a family-based component. Studies involving people with eating disorders, learning disabilities and undernutrition or malnutrition were excluded. Data were extracted on characteristics of the participants, study design, target behaviours, nature of the intervention and study outcomes. A taxonomy was developed and used to classify family involvement in behaviour change interventions. Interventions were also classified according to an existing taxonomy that characterised the behaviour change techniques employed. RESULTS: A total of 21 papers describing 16 intervention studies were identified. Studies were small (mean sample size: 52), heterogeneous, poorly described but with few losses to follow-up (median 15%). The majority were North American and aimed at weight loss. Few studies described a theoretical underpinning to the behaviour change techniques employed. There was a suggestion that spouse involvement increased effectiveness but that adolescents achieved greater weight loss when treated alone. In studies including children, beneficial effects were seen when greater numbers of behaviour change techniques were taught to both parents and children. CONCLUSION: Relatively few intervention studies exist in this important area, particularly studies targeting adolescents, and they highlight continued uncertainty about how best to involve family members. The studies provide limited support for the involvement of spouses. They suggest that parental involvement is associated with weight loss in children, and that use of a greater range of behaviour change techniques improves weight outcomes for both parents and children. The development of future interventions and assessment of factors influencing effectiveness may be improved by paying careful attention to which family members are targeted and how they are involved in the intervention in terms of setting goals for behaviour change, providing support and training in behaviour change techniques.

Interventions to prevent weight gain: a systematic review of psychological models and behaviour change methods.

OBJECTIVE: To identify and review published interventions aimed at the prevention of weight gain. DESIGN: A systematic review of published interventions aimed at the prevention of weight gain. METHODS: Search strategies-we searched eight databases, manually checked reference lists and contacted authors. Inclusion and exclusion criteria-studies of any design, in which participants were selected regardless of weight or age, were included. Interventions targeting a specific subgroup, multifactorial interventions, interventions aimed at weight loss, and those with an ambiguous aim were excluded. Data extraction-data were extracted on behaviours targeted for change, psychological model, behaviour change methods and modes of delivery, methodological quality, characteristics of participants, and outcomes related to body weight and self-reported diet and physical activity. Classification and validation-a taxonomy of behaviour change programmes was developed and used for classification of underlying model, behaviour change methods, and modes of delivery. The data extraction and subsequent classification were independently validated. RESULTS: Eleven publications were included, describing five distinct interventions in schools and four in the wider community. Where diet and physical activity were described, positive effects were usually obtained, but all were measured by self-report. Effects on weight were mixed but follow-up was generally short. Smaller effects on weight gain were found among low-income participants, students and smokers. Many participants in the community-based studies were overweight or obese. Study dropout was higher among thinner and lower-income subjects. CONCLUSION: Interventions to prevent weight gain exhibited various degrees of effectiveness. Definite statements about the elements of the interventions that were associated with increased effect size cannot be made as only one of the five studies that involved an RCT design reported a significant effect on weight. This intervention involved a correspondence programme and a mix of behaviour change methods including goal setting, self-monitoring and contingencies. Future interventions might be more effective if they were explicitly based on methods of behaviour change that have been shown to work in other contexts. Effective interventions would be more easily replicated if they were explicitly described. Effectiveness might be more precisely demonstrated if more objective measures of physical activity and diet were used, and if the follow-up was over a longer period. International Journal of Obesity (2000) 24, 131-143

Fat Watch: a nationwide campaign in The Netherlands to reduce fat intake--process evaluations.

Fat Watch was a four-year campaign carried out in cooperation with retailers and industry, aiming at a reduction of fat consumption by 10% among the Dutch population. Mass media and supermarkets were the main conveyers of the message. Supermarkets participated well in the first (53%) and in the third year (51%), but to a lesser extent in the second year (36%). Campaign awareness in the target group (household shoppers for food) was relatively high in the first year (60%), but dropped in the next two years (40% and 32%, respectively). Combined with prominent mass media messages and with promotional activities of food products by suppliers, supermarkets seem a good channel for dissemination of nutrition information. Fat Watch has proved that cooperation of governmental, industrial and retail organizations for several years with respect to nutrition education activities is possible in the Netherlands.

Results of a community-based campaign to reduce fat intake.

In 1992, a community-based 'Fat Watch' campaign was held in the city of Alkmaar in the Netherlands. The campaign was implemented within the framework of the nationwide mass-mediated 'Fat Watch' campaign (1991-1994), which aimed at a 10% reduction in fat intake among the general Dutch population. The intervention was carried out as a pilot project to study the effectiveness of strategies and activities, and to apply them subsequently in more cities. The campaign aimed primarily at the active involvement of intermediaries. Effects of the campaign were studied by telephone questionnaires among about 500 respondents, before and after the campaign in both the experimental and a control community. The questionnaire was based on the 'attitude, social influence, self-efficacy' (ASE) model. The results showed that 56% of the respondents were aware of a campaign in their community and that the campaign was positively evaluated by those familiar with it. After the campaign, self-rated fat consumption was significantly higher. No differences between the experimental and control community were found regarding attitude, social influence or self-efficacy expectations towards a reduction in fat consumption or intention to buy low-fat food products. However, as opposed to the control community, there was a significant decrease in actual fat consumption between pre- and post-test in Alkmaar. Furthermore, after the campaign, significantly more respondents in the experimental community intended to eat lower-fat food products and reported a behavioral change in the last six months. It was concluded that the campaign was quite successful as far as campaign awareness was concerned, but that it did not result in substantial change of behavior. The limited decrease in fat consumption observed should be interpreted with care.