Obesity prevention

Why this is important

Many studies of interventions to prevent and manage obesity were of short duration, with little or no follow-up, were conducted outside the UK and were poorly reported. There is an urgent need for randomised controlled trials (or other appropriately designed studies, in line, for example, with the transparent reporting of evaluations of nonrandomized designs, TREND statement), with at least 12 months postintervention follow-up.

Studies should use validated methods to estimate body fatness (BMI), dietary intake and physical activity, and should assess the benefits of measures additional to BMI (such as waist circumference in children). Details of the intervention, provider, setting and follow-up times should be reported. The development of a consolidated standards of reporting trials 'CONSORT'-type statement for public health research is strongly recommended. In research on managing obesity in clinical settings, the effects of different levels of intensity of non-pharmacological interventions and follow-up should be assessed. Further research is also needed on the effectiveness of pharmacological and surgical interventions in people with comorbidities such as type 2 diabetes or cardiovascular disease.

Why this is important

There is little UK-based evidence on the effectiveness of multicomponent interventions among key at-risk groups (for example, young children and families and black and minority ethnic groups), vulnerable groups (for example, looked-after children and young people, lower-income groups and people with disabilities) and people at vulnerable life stages (for example, women during and after pregnancy and people stopping smoking).

Interventions should be undertaken in 'real world' everyday clinical and non-clinical settings and should investigate how the setting, mode and source of delivery influence effectiveness. There is a need for research evaluating multicomponent interventions to manage obesity in primary care, because factors such as the types of participant, the training of staff and the availability of resources may affect the results. Future research should:

Why this is important

There is little evidence on the cost effectiveness of interventions, partly because of a lack of outcome measures that are amenable to health economic evaluations. Much of the evidence on the effectiveness of prevention strategies concerns crude measures such as average weight loss rather than response rates. Follow-up is usually short. In clinical research, more information from quality-of-life questionnaires throughout the intervention and follow-up period would help assess how valuable any clinical improvement is to the individual. This would allow greater comparison between types of intervention and improve assumptions made in cost-effectiveness analyses. It would be valuable to run cost-effectiveness studies in parallel with clinical trials, so that patient-level data can be collected.

Why this is important

There are considerable barriers to the implementation of interventions, including organisational structures and personal views of both health professionals and patients. The enthusiasm and motivational skills of the health professional providing support and advice are likely to be key, and interventions may be more effective when tailored to the individual's needs.Further research is required to identify:

Population trends in overweight and obesity

Data on the prevalence of overweight and obesity at national and regional levels (with subgroup analysis by age, gender and social status) are published annually by the 'Health survey for England' (HSE) and the 'Welsh health survey'. The continued collection of such data at national and regional levels is strongly recommended. The 'Health survey for England' also provides detailed data on children and on black and minority ethnic groups about every 5 years. To allow full analysis of trends, more frequent collection of data among these and other vulnerable groups at national and local levels is encouraged.

Local and national action

Although considerable action is being undertaken at a local level that could directly or indirectly have an impact on the prevention or management of obesity, little evaluation is being undertaken. This observation is reflected in the 2005 Dr Foster survey of obesity services, which found that only 15% of primary care organisations monitored interventions such as physical activity programmes and exercise on prescription. Many potentially important broader community policies are also not evaluated in terms of their health impact – examples include congestion charging, which is implemented to address traffic rather than health issues, and safer routes to schools.

It is therefore recommended that all local action – including action in childcare settings, schools and workplaces – be monitored and evaluated with the potential impact on health in mind. An audit of health impact should also be undertaken after each change has taken place. The need to evaluate projects should be taken into account when planning funding for those projects. It is recommended that the evaluation of local initiatives is carried out in partnership with local centres that have expertise in evaluation methods, such as health authorities, public health observatories and universities.

There is also limited high quality long-term evaluation of national schemes that are implemented locally and may have an impact on weight, diet or physical activity (such as interventions promoting a 'whole-school approach' to health, Sure Start initiatives and exercise referral schemes for children). It is therefore recommended that all current and future actions be rigorously monitored and evaluated with their potential health impact in mind. Evaluation of campaigns (including social marketing campaigns) should go beyond the 'reach' of the campaigns and more fully explore their effectiveness in changing behaviour.

Clinical practice

In clinical practice there is a need to set up a registry on the use of orlistat in young people. There is also a need to undertake arrangements for prospective audits of bariatric surgery, so that the outcomes and complications of different procedures, their impact on quality of life and nutritional status, and the effect on comorbidities can be monitored in both the short and the long term.