7. The Obesity Epidemic needs to be taken seriously
Obesity is increasing. This is a national and international problem which affects people across all ages, genders and deprivation categories, although there are higher rates amongst older populations, those with learning difficulties, women and in areas of multiple deprivation. One fifth of pre-school children and 60% of adults are either overweight or obese (50) .
The proportion of the NHS Greater Glasgow and Clyde population either overweight or obese has increased rapidly by 12% in 8 years, with more than 60% of adults and 20% of pre-school children now affected (Figure 7.1).
This rising prevalence of being overweight and obese is a phenomenon that can be ascribed to a general increase in the average weight of the entire population rather than a problem reserved to specific subgroups of the population. Figure 7.2 shows that this is a problem affecting the whole population demonstrated by a ‘shift to the right’ of the population weight distribution over 8 years.
Obesity can be thought of as part of a continuum which stretches from underweight, through normal weight to overweight and obesity.
Obesity is defined for adults as any individual body mass index value over 30 (with overweight defined as a BMI between 25 and 30). This measure is less useful in children since there is a normal and wide variation in the BMI measure as children grow. Obesity trends in children are therefore monitored by comparing the BMI distribution of today with a reference distribution of childhood BMI from 1990.
Causes and effects of obesity
In simple terms, the obesity epidemic results from an imbalance between the amount of energy we collectively consume in our diet and the amount of energy we expend. Complex interactions occur at an individual level, amongst families, in communities and in society as a whole which combine to deliver this energy imbalance. This phenomenon is best explained as the presence of an ‘obesogenic environment’ where the circumstances in which we live contrive to bring about a continuous rise in the prevalence of obesity. This includes the commercial marketing of food, the urban environment, the transport system and popular culture (51). Taken together these interlinked systems combine to create a ‘runaway weight gain train’ upon which the population is riding (52).
Obesity is associated with numerous health problems such as diabetes, heart disease, arthritis, high blood pressure, some cancers and mental health problems. Vulnerability to these illnesses varies, for example, with age, gender, co-morbidity and ethnic origin. Its rising prevalence therefore represents a threat to the current trends in continuous health improvement for most conditions in Scotland.
Preventing and managing obesity
A number of organisations have conducted studies of the evidence base for the prevention and management of obesity. They include the Faculty of Public Health (53), the Cochrane collaboration (54), Health Scotland (55, 56), Scottish Intercollegiate Guidelines Network (57), the World Health Organisation (58), the House of Commons Health Committee (59) and National Institute for Health and Clinical Excellence (60). The broad conclusion of this huge volume of work is that the evidence base for effective measures to successfully prevent or manage obesity is limited. However there have been few studies on the more ‘upstream’ societal determinants of health that cannot easily be studied using the traditional framework of randomised trials.
Figure 7.3 shows a broader approach to ways in which we take action on obesity.
NICE has developed model patient flow diagrams based on the evidence for the management of obesity. These include evidence for using appetite suppressant drugs and surgery for those morbidly obese. There is now widespread recognition that there is very little evidence to support the traditional approach of telling people to “pull yourself together, eat less and exercise more”. The recommendations for preventing obesity in national guidelines are summarised in the figure 7.4.
Figure 7.4 - Recommended actions for the prevention of obesity in NICE guidelines 2006 (61, 62)
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How NHS Greater Glasgow and Clyde and its partners are responding
NHS Greater Glasgow and Clyde and its partners are working to tackle the obesity epidemic in a number of ways. For example they are:
Despite these activities the proportion of the population who are overweight or obese continues to increase. The activities that are designed reduce obesity are being overpowered by the ever-accelerating drivers of obesity. Unless we reverse the development of the obesogenic environment, which combines with our genes to make overweight or obesity more normal, we will need to treat an almost exponential rise in the medical consequences of obesity, and deal with obesity in a soaring number of people to prevent these consequences. This will involve action by many agencies at many levels, but NHS Greater Glasgow and Clyde should lead the development of an environment for weight reduction. This can be done through the partnerships it has with local authorities through CHPs. NHS Greater Glasgow and Clyde should encourage all relevant agencies to make the prevention of obesity a priority and support them to make the necessary changes.
The Glasgow City Physical Activity Strategy Let’s Make Glasgow More Active is an example of good practice. The Strategy takes a broad approach and complements the current Commonwealth Games Bid by providing a balance between recognition, celebration and support for the role of sport.
The Strategy’s main objectives are to:
Other community planning partnerships are also developing physical activity strategies, for example Renfrewshire launched their strategy in June 2007.
In addition, the NHS should further develop its clinical pathways for identifying and managing the people who would benefit from treatment to reduce weight. This is particularly the case for children in NHS Greater Glasgow and Clyde.
Key public health messages and priorities for action
In order to reverse the obesity epidemic two things need to happen:
The population as a whole has to consume less food energy. This is only likely to happen when food policy is based on the interests of health. Examples of this approach might include:
The population as a whole needs to expend more food energy. This is only likely to happen when the barriers to active transport (such as walking, cycling and the use of public transport) are removed and when limits are applied to sedentary forms of transport (such as cars). Examples of this approach include: