Obesity is on the increase. By 2000, it is predicted that 18 per cent of men and 24 per cent of women in the UK will be obese. And this will have an impact on their quality of life.
It is generally accepted that the benefits of healthcare must be evaluated alongside the costs of achieving them, and that quality of life should represent an integral part of the benefits package.
But there is no agreement on what factors make up quality of life, although it is agreed that this quality is multi-dimensional, with physical, psychological and social functioning and general well-being among the dimensions.
Physical functioning concerns mobility, self care, daily living activities and a range of other activities. Psychological functioning encompasses cognitive functioning as well as depression and moods such as anger. Social functioning assesses social, recreational, employment and sexual functions. Finally, overall well-being evaluates the individual's general health perceptions and life satisfaction.
Quality of life analysis provides a valuable perspective when evaluating new drug treatments, particularly when comparing alternative therapies for chronic disease, where there are minimal differences in patient survival. Despite scepticism concerning their perceived subjectivity, quality of life measures are gaining importance for evaluating healthcare and lifestyle change in such diseases.
Effects of obesity
Obesity is defined as an excess of adipose tissue (body fat), and its prevalence has doubled in the UK in the past decade. This increase is repeated in all westernised societies.
It is now accepted that obesity is not entirely explained by either inappropriate eating behaviour or insufficient exercise. The complexities of obesity encompass animal models of obesity, genetics, biochemical changes and are compounded by the psycho-social and cultural factors which create susceptibility to human obesity.
'It is safe to assume that there is no single personality type that underlies obesity. The idea of the happy-go-lucky fat person is in reality a myth,' a US study notes.1 Children associate being overweight with poor social functioning, low academic achievement and reduced levels of fitness and health.2
Obesity is highly stigmatised in many industrial countries, being seen as something that is self-inflicted, and an indication of lack of will- power.3
Conversely, weight loss is associated with greater social interaction and improved physical and mental functioning.
The co-morbidities associated with obesity are well documented. The diseases with the highest associated risks are coronary heart disease, diabetes, musculoskeletal disorders and certain cancers.
Implications for the health service
Preliminary findings from a study we are undertaking in North West region of the costs of coronary heart disease emphasise the resource burden imposed on the NHS.
The study analysed data from a North West region health needs survey of over 60,000 people carried out in 1992. Questionnaires had been returned by nearly 38,000 people giving basic and demographic, socio-economic and self-reported health status information.
Body mass index was calculated from information on height and weight and correlated against the individual's self-reported health status in a range of areas, from heart disease to haemorrhoids. This enabled an estimate to be made of the excess health resource used by those classified as obese (BMI of 30 or more).
The study shows that effective interventions for obesity would lead to savings of 10 per cent in the cost of treating men and up to 13 per cent in the cost of treating women. The timing of changes in patients' health status indicate that hypertension allied with obesity in the early 30s may be a predictor for the development of serious co-morbidities later in life.4
New initiatives in public health emphasise the effect that lifestyle, housing and employment exert on health. At the same time the NHS is moving from a paternalistic to a partnership model. Evaluation of health interventions should reflect such changes. This requires the clinical evaluation of obesity to be supplemented by a quality of life assessment. This is an invaluable method of evaluating costs and benefits of obesity from all perspectives.
Impact on quality of life
In looking at the effect of obesity on quality of life, some studies have placed more emphasis on poor physical functioning while others report poor psycho-social functioning.
But there is no doubt that apart from its associated medical conditions, obesity produces a host of further complications. Research suggests that one of the primary reasons individuals seek treatment for obesity is not the dire medical consequences but the impact their body weight has on their lives.5
In a large study, Mathias et al assessed health-related quality of life and health-state preference in people with obesity.6 They concluded that obesity may have a negative effect on health-related quality of life because of decreased psychological well-being, stigmatisation and less social integration. This study is the first comprehensive look at a moderately obese population. Many previous studies have only been able to detect differences between morbidly obese people and those of normal weight.
A 1997 study on working life found that workers rated colleagues with cancers, low vision, facial burns, diabetes and limb amputations as similar to themselves in terms of value and promotion potential. But fellow employees who were obese or suffering from depression were perceived less favourably, even if they had the same qualifications.
Job discrimination in the form of low wages, getting the sack, being de-selected at interview and being passed over at interview are frequently reported by obese people, and job satisfaction has been shown to increase with weight loss. This finding emphasises the importance of job satisfaction as a quality of life measure.
Quality of life studies with obese people indicate that most evaluate their health state as undesirable. Morbid obesity causes impaired quality of life beyond the impact of medical complications of the disease. And patients' perceptions of their own health state can have an important effect on compliance with treatment, and hence its outcome.
The perceptions of the patient should be explicitly incorporated into healthcare decision-making. Such a partnership approach would enhance clinical effectiveness in an area where the motivation and self-esteem of the patient is a fundamental determinant of the success or otherwise of therapeutic interventions.
Effective quality of life assessment allied with cost analysis produces a complete picture of obesity and allows the implementation of clinically effective treatment, with due regard to resources.
Lynne Roberts is research fellow, and Alan Haycox is senior lecturer in health economics, prescribing research group, pharmacology and therapeutics, Liverpool University.
Severe obesity is on the increase in Britain and accounts for considerable excess hospital costs.
The benefits of new treatments need to be assessed in terms of psychological, as well as physical, benefits to patients.
Programmes aimed at changing lifestyles will be effective only when obesity is considered in terms of all its effects on the individual.
1 Allison D. Handbook of Assessment Methods for Eating Behaviours and Weight-related Problems: measures, theory and research. US: Sage, 1995.
2 Hill A, Silver E. Fat, Friendless and unhealthy: nine-year-old children's perception of body shape stereotypes. International Journal of obesity and related metabolic disorder 1995; 19: 423-430.
3 Allon N. The Stigma of Obesity in Everyday Life, from Psychological Aspects of Obesity: a handbook. Editor: Wolfan B. New York: Van Nostrand Reinhold, 1981.
4 Bagust A, Roberts B et al. The Cost of Obesity and the Potential for Effective Intervention. To be published.
5 Fontaine K, Bartlett K. Estimating Health-Related Quality of Life in Obese Individuals. Disease Management and Health Outcomes J 1998; 3: 61- 69.
6 Mathias S, Williamson C et al. Assessing health-related quality of life and health state preferences in persons with obesity: a validation study. Quality of Life Research 1997; 6(4): 311-322.