Evidence, theory and context - using intervention mapping to develop a school-based intervention to prevent obesity in children (original) (raw)
Intervention Mapping
The six main steps of IM (Figure 1) are: i) needs assessment; ii) detailed mapping of programme objectives and their behavioural and environmental determinants; iii) selecting techniques and strategies to modify the determinants of behaviour and the environment; iv) producing intervention components and materials; v) planning for adoption, implementation and sustainability; and vi) creating evaluation plans and instruments. IM uses behavioural theory and research evidence to develop specific learning and change objectives for the target population and to identify the personal and external determinants of these objectives. Theory and other considerations (e.g. stakeholder opinions, feasibility data) also guide the choice of intervention methods and strategies to achieve these objectives. We used a variety of methods to gather the appropriate information to enable us to produce a feasible and acceptable intervention that has the potential to change behaviours at a school, child and family level. These included literature reviews, discussions with stakeholders (teachers, head teachers, education advisors, local public health leads in physical activity and obesity) and experts in behavioural science and obesity research. We also carried out focus groups with children and interviews with parents and teachers during early pilot work to inform our selection of intervention techniques and strategies and to ensure that these remained feasible to deliver within normal school activities.
The following sections provide a summary of the first 4 steps of the IM process used to produce the HeLP intervention. Steps 5 and 6 involve programme implementation, adoption, monitoring and evaluation and are not presented here. While the steps are described in linear fashion they are, in fact, iterative. For example, defining a more specific behaviour change objective (e.g. parents need to buy and provide healthier snacks) might lead to the consideration of additional behavioural determinants (those which affect parental shopping behaviours as well as those which affect the child's eating behaviour).
Step 1: Needs Assessment
The IM process begins with a needs assessment of the health problem, which includes identification of the problem behaviours (and to some extent their determinants) and of desired programme outcomes as well as the environmental conditions associated with the problem.
Reviewing the evidence base
The starting point was to review the literature to identify (i) risk factors for childhood obesity and children's current eating/drinking and physical activity behaviours (ii) the determinants of these behaviours and (iii) apparently successful and unsuccessful components of previous school-based interventions to prevent and reduce obesity.
(i)Possible risk factors for obesity
Obesity results from an imbalance between consumption and expenditure of energy. Controlled experimental and epidemiological studies suggest a number of dietary risk factors associated with increased energy intake in children and adults. These included, diets with a high energy density [8] usually characterised by foods high in fat and low in fibre, including fast food [9, 10] and large habitual portion sizes [11]. Experimental studies also report that liquid calories have lower satiating properties than solid food [12] and epidemiological studies report an increased risk of weight gain or obesity in consumers of sugar-rich drinks. A single carbonated drink per day can add 10% to a child's energy intake [12]. According to the National Diet and Nutrition Survey (2008/9), in the UK children's intake of non milk extrinsic sugars (NMES) provides 15% of food energy [13], compared to a recommendation of not more than 11% [14]. Carbonated soft drinks are a major source of NMES providing 19% of NMES intake in children aged 4-10 and over one-third in children aged 11-18 [13].
Reduced energy expenditure has also been associated with weight gain [15] and numerous studies in adults and children reported an association between lower weight gain and higher levels of physical activity [16]. Stratton et al reported a decrease in the levels of cardiovascular fitness in 9-11 year olds in England between 1997 and 2003 while the prevalence of obesity increased over the same time period [17]. Children's TV viewing time and time spent playing electronic games has been associated with overweight and obesity [18–20], total calorific intake [21] and the consumption of snack foods [22]. Longitudinal data from the Avon Longitudinal Study of Parents and Children (ALSPAC), found strong associations between children's fat mass at age 14 and their physical activity at age 12 [23]. We also know that today's children are spending more time in front of the television or computer screen than in previous generations - an average of two and a half hours of TV and 1 hour and 50 minutes online a day [[24](/article/10.1186/1479-5868-8-73#ref-CR24 "Childwise: The Childwise Monitor Trends report 2010/11. Childwise. 2011, Childwise, Norwich, [ http://www.childwise.co.uk/childwise-published-research-detail.asp?PUBLISH=53
]")\]. (i.e. nearly 4 1/2 hours a day of screen time). An attempt to encourage children to replace screen-based sedentary behaviours with more active pursuits is clearly an appropriate aim in preventing obesity in children and promoting a healthy lifestyle.(ii)Determinants of behaviours
A variety of family and social determinants affecting children's eating and activity behaviours have been identified. For eating, these include food preferences, food availability and accessibility, modeling (copying the behaviour of others), mealtime structure (social context of meals, the role of TV during mealtimes, eating out, portion size, school meals, snacking habits), feeding styles (the caregivers approach to maintain or modify children's behaviours with respect to eating) and socio-economic and cultural factors (e.g. family time constraints, education, income, ethnicity and culture) [25]. In terms of children's physical activity, parental support (e.g. transporting the child, observing the activity, encouraging the child, providing equipment, participating with the child and reinforcing physical activity behaviours) has been identified as a key determinant both directly and indirectly through its positive association with self efficacy perceptions [26]. Griew et al recently reported that children's school time physical activity varied according to the primary school they attended even after accounting for individual demographic and the school compositional factors with a 'school effect' explaining 14.5% of the variation in pupils' school-time physical activity [27]. However, it is less clear that school based activities have a substantial effect on total, as opposed to school time, activity. In a study of 3 schools from one area, with different sporting facilities and opportunity for physical activity in the curriculum, Mallam et al (2003) reported large differences in school time activity levels but virtually no differences in the total activity of the children [28].
This research suggests that while it appears that schools have the potential to create a positive physical activity culture that can influence whether children engage in physical activity it will be crucial in intervention studies to assess whether any effects translate in to changes in total as opposed to only school time activity.
Drawing on the social ecological approach [[29](/article/10.1186/1479-5868-8-73#ref-CR29 "Egger G, Swinburn B: An "ecological" approach to the obesity pandemic. British Medical Journal. 1997, 315: 477-480.")] we began from the theoretical perspective that, while both eating and activity behaviours in children are partly determined by choices made by the children, they are highly dependent both on direct intervention by parents (e.g. the food provided, opportunities for physical activity) and by patterns of behaviour within the family, within the school and within peer groups. As children get older the relative importance of self directed, as opposed to family directed, behaviours increases and these behaviours are influenced by wider social factors which include the school environment and peer group norms. Therefore any intervention we designed needed to affect behaviour through influencing the children, their families and the school environment. There is some evidence from previous studies of interventions in children that the use of drama/theatre can be an effective tool to engage children, increase knowledge and change behaviours [30–33]. For example, in an obesity prevention programme aimed at low income children and their parents, an after school theatre-based intervention was shown to motivate and engage both parents and children and increase awareness of the need for making changes. However, the authors did conclude that theatre alone is not enough to lead to behavioural change and that the next step should be to incorporate this delivery method into more comprehensive programmes with both educational and environmental components [31]. Two small studies in primary schools in the UK based on drama/the arts reported increases in vegetable, salad and fruit juice consumption [32, 33]. Although both these studies had serious methodological weaknesses, the use of drama to engage children to change specific behaviours looked promising and was explored at length with experts from drama and education as a possible implementation strategy in step 3 of the intervention mapping process.
We were mindful that there were other key drivers including intrinsic factors such as genes and the wider social environment but these are less modifiable and so were not considered as potential points of intervention.
(iii) School-based interventions
The most recent systematic review (2009) of controlled trials of school-based interventions identified 38 studies; 3 dietary intervention only, 15 physical activity only and 20 combined diet and physical activity [34]. The authors concluded that there was insufficient evidence to determine the effectiveness of dietary interventions alone, but suggested that interventions which increase activity and reduce sedentary behaviour may help children to maintain a healthy weight, although results were short-term and inconsistent. Results for combined diet and activity were also inconsistent, although there was a suggestion that the combined approach might be more effective in preventing children becoming overweight in the long term. Social Cognitive Theory (SCT), which proposes that a dynamic interaction exists between personal, behavioural and environmental factors, provides a basis for many of these programmes, particularly the constructs of self efficacy, behavioural capability (knowledge and skills to perform a behaviour), outcome expectations, self regulation and reinforcement [35]. Environmental conditions of eating behaviour such as school lunch provision and parental/home environment were often targeted [36, 37]. A review of reviews of effective elements of school health promotion across behavioural domains (substance abuse, sexual behaviour and nutrition) found that five elements from the highest quality reviews were found to be effective for all three domains using two types of analysis. These were use of theory; addressing social influences (especially social norms); addressing cognitive behavioural skills; training of facilitators and multiple components. Using one type of analysis only, another two elements were identified: parental involvement and a large number of sessions [38].
The authors concluded that the 5 elements identified should be primary candidates to include in programmes targeting these behaviours.
Stakeholder consultation
A second approach to needs assessment is to collect information to enable a deeper understanding of the context or community in which the intervention is to be delivered [7]. The next step in our needs assessment was therefore to run a workshop with practitioners, policy makers and researchers from education, child health, sports science, the local PCT and the local healthy schools team. In the workshop we addressed the nature of the problem and the findings of our literature review, seeking ideas about possible behavioural objectives for schools, children and their families and what the desired outcomes of the programme should be.
This workshop resulted in agreement about four key principles which it was suggested should guide our intervention design. Firstly, that a public health approach should be adopted including all children rather than targeting the overweight. The adverse health consequences of obesity are not limited to those at the extreme end of the BMI distribution and, although most children remain lean, many will gain weight as adults. In addition, separating children within a class for special intervention risks stigmatising them. Secondly, the intervention needed to engage parents and offer them strategies through which they could directly (through parenting) or indirectly (through the creation of supportive environments) foster the development of healthy eating and activity behaviours among their children/family. Thirdly, in order to provide an intervention that was not only feasible and acceptable to schools, but had potential for long term sustainability, the intervention should dovetail with healthy lifestyle initiatives already present in schools and aim to meet National Curriculum requirements for the age group targeted, something previously recommended by Doak et al (2006) in a review of interventions and programmes to prevent obesity in children [39]. Finally, the methods chosen to deliver the intervention to children and parents not only needed to engage, motivate and inspire but should also be realistically deliverable by teachers and relevant external groups operating within a school setting.
Outputs
Based on the above needs assessment process we decided to develop an intervention which aimed to support children to achieve small sustainable changes across childrens' patterns of diet and physical activity but with a focus on three key behavioural objectives:
- to reduce the consumption of sweetened fizzy drinks
- to increase the proportion of healthy snacks consumed and
- to reduce TV viewing and other screen based activities.
Step 2: Detailed mapping of programme objectives
Step 2 provides the foundation for intervention development by specifying in detail who and what will change as a result of the programme. The products of step 2 are proximal programme objectives or PPOs. These are statements of demonstrable behaviours (in the target group) or changes in the environment that need to occur in order affect the determinants of the overall behavioural objectives that have been identified in step 1 (and further refined in step 2). To define PPOs, we first defined key behavioural objectives (see above) and broke these down into smaller steps (performance objectives) and then identified the determinants of each performance objective. Then we specified 'proximal programme objectives' (i.e. the most immediate targets of intervention - what needs to be learnt or changed in order to modify behavioural determinants and consequently the key behavioural objectives).
As the aim of our intervention was to develop a school-based intervention which was delivered to children but was able to influence parents and the school as well, activities needed to include parents/families, teachers and the senior management team (SMT). Further, more specific behavioural objectives, called performance objectives (POs) were developed for each group (children, parents/family, teachers, SMT). These constituted individual behaviours, motivations, abilities and environmental opportunities in the home and within the school for each group in order for the three key behavioural objectives to be achieved. The performance objectives developed for the parents/family, teachers and the SMT were focused on engaging the school and the children's families in order to create the necessary conditions to enable children make sustainable changes to their eating and activity behaviours. For example, at the outset, a PO for the SMT was for them to 'buy into' the Programme and believe it would benefit the school and the children and would dovetail with the existing year 5 curriculum and school initiatives already in operation. For the purposes of this paper we will confine our examples to the performance objectives related to the child, however, a detailed intervention specification supporting this paper is available to view (See Additional file 1) which shows the POs, determinants (change targets), BCTs and methods of delivery for all the target groups.
a) Defining overall behavioural objectives
The creation of a behavioural objective requires breaking down the desired outcome, in this case, preventing obesity, into component parts that influence or are required to achieve the desired outcome. The three key target behaviours, reducing consumption of sweetened fizzy drinks, increasing the proportion of healthy snacks consumed and reducing TV viewing and other screen-based activities were expanded into a set of sub-component behaviours (performance objectives, POs). These performance objectives clarified the exact behavioural performances expected from children, parents and teachers in order to meet these key objectives and referred to individual level behaviours, motivations, abilities as well as to environmental opportunities for such behaviours at the home and school level. As involvement of parents was vital in achieving the three key target behaviours, we knew we needed children to clearly communicate the messages to their parents and engage them in supporting their goals. This was originally construed as a PPO related to the determinants of social support, modelling and reinforcement but was promoted to a PO so that the intervention could explicitly focus on strategies to promote this dialogue between the child and their family. The iterative process of identifying performance objectives was added to over time as the mapping process identified additional issues. For example the concept of enabling children to recognize and resist temptation for unhealthy snacks was originally a PPO (which aims to address the determinant of 'urges for unhealthy foodstuff' as related to the objective of 'reducing unhealthy snacks') which we also promoted to a performance objective to allow a more detailed analysis of this key issue. Although this process was time consuming, it was useful in creating a more focused and considered intervention.
b) Identification of Determinants
In order to specify our 'change targets' i.e. those potentially modifiable determinants of obesity related behaviours we i) reviewed the determinants of children's eating and physical activity behaviours reported by experimental and epidemiological studies and components of previous school-based interventions to prevent and reduce obesity; ii) sought expert opinion from an advisory panel of researchers in the field and behavioural scientists; and iii) made reference to theories of behaviour and/or behaviour change. The determinants were categorised as personal (factors within the individual under their direct control) or external (factors outside of the individual that can directly influence the health behavior or environmental conditions). The final list of determinants to be targeted is provided in Table 1. These were selected based on their links to theoretical models of behavior change which have formed a basis for previous school-based interventions and their potential to be modified within a school setting.
Table 1 Examples of determinants of eating and physical activity behaviour in children targeted by the Healthy Lifestyles Programme
A focus on delivering the Programme in such a way that children enjoyed the activities and were motivated to participate was also seen as a key determinant for a number of POs, as affective responses are linked to both physical activity and eating behaviours. It is likely that children will be motivated and enjoy activities if they have positive attitudes towards the behaviour [40], feel competent to make changes [41], perceive significant others to be motivated and perceive they have some control over outcomes [42]. The main determinants or 'change targets' for the HeLP Programme therefore, were (i) knowledge and skills (ii) self efficacy, (iii) self awareness, (iv) taste, familiarity and preference, (v) perceived norms (vi) support, modelling and reinforcement from family members and (vii) access and availability of opportunity. Having selected our change targets or determinants the next step was to identify the specific behaviours necessary to modify them.
c) Define proximal program objectives
The final part of this step is to define the proximal programme objectives (PPOs) by mapping performance objectives (row headings in tables 2, 3 and 4) against determinants (column headings in table 2, 3 and 4) in a table to form a matrix. In the tables, cells created from personal determinants record what the target group should do and/or know and cells created from external determinants record what should change in the environment in order for there to be a positive impact on each determinant so that the performance objective can be achieved. These end statements are the PPOs. For example, for children to communicate healthy lifestyle messages to parents and seek their help and support, change in three personal and two external determinants are required (see Table 2). From a personal perspective, the child needs specific knowledge and skills to communicate the messages to their parents and seek their help and support (taught throughout the intervention using a variety of methods) and perceive that their peers are talking about the project and also seeking their parents support. Practising communication through role play and engaging parents using homework tasks, drama productions and school assemblies may increase self efficacy in communicating messages to parents and making suggestions for support. From an external perspective, the child requires support and reinforcement from parents, teachers and peers. This increased communication with parents/family needs to increase family awareness of healthy lifestyles and in turn lead to the family increasing availability and accessibility of healthy snacks and active pursuits at home.
Table 2 Matrix of performance objectives and determinants for 'Establish Motivation'
Table 3 Matrix of performance objectives and determinants for 'Take Action'
Table 4 Matrix of performance objectives and determinants for 'Stay Motivated'
The end point of step 2 in the intervention mapping process, i.e. defining proximal programme objectives, is an iterative process and we moved back and forth between the tasks of defining POs and their associated determinants from the ones targeted in the HeLP Programme (see Table 1) and the creation of statements of demonstrable behaviours. e.g. 'practices skills to seek parental support' that would modify a particular determinant and thus help achieve the performance objective. This process produced an overwhelming amount of information which we had to condense in order to develop a feasible and acceptable intervention within the school setting.
During the process of creating the matrix, in order to guide the sequential order in which behaviour change techniques were delivered in our intervention, we decided to map performance objectives onto a process model of behaviour change. The Health Action Process Model (HAPA) [42] was selected as a 'starting point' as it is consistent with the theoretical models of behaviour change mentioned earlier and suggests that behaviour change occurs through a sequence of adoption, initiation and maintenance processes. This phased model implies a clear order of distinct actions which is easily understood and is compatible with a sequential application of techniques spread across the curriculum of a school year. By taking these phases into account, performance objectives and their associated PPOs were mapped onto three processes of behaviour change; Establish motivation (develop confidence and skills, make decisions); Take action (create an action plan and implement it); Stay motivated (monitor progress, assess and adapt goals).
Tables 2, 3 and 4 present matrices of performance objectives and a selection of the key determinants targeted in the HeLP intervention for each of the three processes of behavior change. The combination of performance objectives, and behavioural determinants, generates (in the cells of the table) the proximal objectives for the Programme (PPOs). These have then been mapped onto the appropriate process of behavior change in the HAPA model. This provided a clear framework to guide the selection and sequencing of the behavior change techniques and practical strategies which constitute the intervention.
Step 3: Specify behaviour change techniques
The product of step 3 is an inventory of behaviour change techniques selected to match each proximal programme objective. A behaviour change technique (BCT) e.g. 'model/demonstrate behaviour' is a technique designed to change a specified theoretical process or determinant of behaviour. For example, using strategies in the intervention that enable children to practice a targeted behaviour and/or see role models perform the behaviour, is designed to increase self efficacy (confidence in being able to perform the target behaviour), which is a construct of social cognitive theory.
Finding appropriate techniques begins with the question "How can the learning and change objectives (the PPOs) for each performance objective be accomplished?" Methods for identifying suitable techniques included a) discussions with stakeholders, and experts in behaviour change (behavioural science academics/health promotion staff); b) reference to a taxonomy of behavioural change techniques [43, 44]; c) consideration of theory and practice in other school-based interventions; d) applying criteria for feasibility, acceptability and cost within a school setting.
A range of suitable BCTs were then selected and included: role modelling, skill and knowledge building, communication skills training, self monitoring, problem solving, modelling/demonstrating behaviour, barrier identification, goal setting, decision balance and social support. For example, to practice skills to communicate the desired healthy lifestyle messages to their parents and seek their support, children modelled and demonstrated the behaviour by participating in a variety of role play scenes, followed up with discussions of issues led by the drama facilitator. Many BCTs may need to be applied to bring about a single PPO e.g. for children to 'practice skills to resist temptation' (PPO number 32, see Table 2), the BCTs used were 'prompt barrier identification', 'problem solving', 'decision balance', 'model/demonstrate behaviour' and communication skills training'. This linked to the PO of 'understand and resist temptation'. (see Table 5).
Table 5 Behaviour change techniques and strategies for performance objectives associated with 'Establish Motivation'
Step 4: specifying practical strategies and designing the intervention
The implementation strategy is simply the process for delivery of a particular behavior change technique. The strategy needs to be appropriate for the target population and the setting in which the intervention will be conducted. We were mindful (as per our needs assessment) that strategies chosen needed to be deliverable by teachers and relevant external groups operating within a school setting, dovetail with healthy lifestyle initiatives already going on in schools at the time and, where possible, meet National Curriculum requirements for this age group.
a) Specifying implementation strategies
It was clear the strategies chosen to deliver the key messages needed to inspire and motivate the children so that they discussed the Programme at home with their parents and each other. Previous research has suggested that drama may be an appropriate means of engaging children, increasing knowledge and changing health behaviours [30–33]. Following discussions with experts in education and drama, it was hypothesised that interactive drama based activities where the children take ownership of the issues was more likely to motivate children to become engaged with the process, make changes and to engage their parents than passive receipt of messages. We also hypothesised that, if the children were involved in the development of materials, including the scenarios they produce (facilitated by actors), they would be more likely to be receptive to the health messages. Drama sessions were also compatible with the existing school curriculum and could provide a framework within which to deliver many of the proposed behaviour change techniques in a way which is accessible and engaging for children.
Table 5 presents a summary of behaviour change techniques and implementation strategies chosen to accomplish PPOs (not shown) for each performance objective related to 'establishing motivation'. To view the table showing techniques and strategies for 'take action' and 'stay motivated' see Additional file 2.
b) Designing the Programme
Utilising the Health Action Process Model, our chosen implementation strategies were then ordered to create three intervention components (components 2-4) following the sequence of the three broad behaviour change processes in the HAPA model, with an additional component (component 1) designed to create a receptive context within the school (Table 6). The HeLP intervention runs over 3 school terms (Spring and Summer term of year 5 and Autumn term of year 6) so that it is feasible and acceptable to schools and to encourage transfer of knowledge and skills into year 6. Table 6 provides a summary of each component of the intervention (with timescales), summarised implementation strategies and their associated performance objectives. Performance objectives marked * for component 1 have not been discussed in this paper as they do not relate directly to the child but a detailed intervention specification showing performance objectives for all target groups is available to view (See Additional file 1).
Table 6 The HeLP Programme and associated POs