Modern Global Epidemic Of Obesity

Modern Global Epidemic Of Obesity In his Annual report of 2002, the UK Chief Medical Officer has described it as a health time bomb. Overweight and obese children are likely to stay obese into adulthood with increased risk of associated major chronic diseases. Consequently, socioeconomic disparities observed in obesity supplement socioeconomic inequalities in health (Law et al., 2007). Prevention of childhood obesity therefore is critical. In this paper, the author will examine the complex interaction of social, economic, biological and environmental determinants of health that may explain the recent explosion, shifts in demographic trends of this worldwide problem, and briefly explore lifestyle and behavioural factors that may create particular risks. A discussion about causes, complications and treatment options of childhood obesity will follow. The author will review and analyse determinants and health policy initiatives, critically appraise various global, national and local strategies, initiatives and interventions, which aim to prevent obesity in childhood and examine their link to conventional health promotion models and theories. By critically examining the range of interactions and existing initiatives, the author seeks to propose appropriate interventions to tackle the growing challenge of childhood obesity. Key words: childhood obesity, inequalities, policy, strategy, prevention, health promotion DEFINITION Obesity/Adiposity is defined as a condition characterised by excessive body fat. Body fat can either be stored predominantly around the waist or around the hips. Body Mass Index (BMI) is used to measure obesity and defined as: Bodyweight (Kg) (Keys et al., 1972) Height (m) 2 BMI is useful in clinical practice and epidemiologic studies, but has limitations. Freedman et al. (2004) reported that although BMI is a good measure of fat mass in children with high BMIs, it is not a reliable indicator in thinner children. Two international datasets that are widely used to define overweight and obesity in pre-school children are International Obesity Task Force (IOTF) reference and World Health Organisation (WHO) Child Growth Standards (2006). None is superior to the other and both tend to underestimate or overestimate the prevalence when used on the same population (Monasta et al. 2010). Thresholds for obesity in children in UK (and Scotland) are measured by referring to UK National BMI classification system that uses reference curves based on data from several British studies between 1978 and 1990 (Cole et al, 2000). Children are classified as overweight or obese using the 85th and 95th percentiles as cut points. PREVALENCE, trends and costs Obesity has become an epidemic in many parts of the world and surveys over the last decade have documented the rapidly increasing prevalence of obesity and overweight among children along with rising socioeconomic inequalities (Wang and Lobstein, 2006; Lobstein, Baur and Uauy, 2004). The latest WHO report (Mercedes, Monika and Elaine, 2010) based on surveys from 144 countries estimates that globally, 43 million children (including 35 million in developing countries) are overweight and obese and another 92 million are at risk of overweight. This corresponds to a prevalence increase from 4.2% in 1990 to 6.7% in 2010. In England, 2008 figures showed 16.8% of boys aged 2 to 15, and 15.2% of girls were classed as obese, an increase from 11.1% and 12.2% respectively in 1995 (The Health and Social Care Information Centre, 2010). Amongst Organisation for Economic Cooperation and Development (OECD) countries, only USA and Mexico having higher levels of obesity than Scotland and this is expected to get worse even with current intervention practices. Scottish Govt. report (2010) states that in 2008, 15.1% children were obese and 31.7% were overweight. Amidst this doom and gloom scenario are recent reports (Stamatakis, Wardle and Cole, 2010) showing trends in overweight and obesity prevalence have stabilized or reversed in pre-teens and early teenage years in France, Switzerland and Sweden. In the US too, the obesity epidemic may be stabilising (Ogden et al.,2010) but it is too early to know whether the data do reflect a true plateau (Cali and Caprio, 2008). Similarly, in England, trends in overweight and obesity prevalence have levelled off after 2002 (Stamatakis, Wardle and Cole, 2010); however, socioeconomic inequalities have deepened. Healthcare (direct) costs of obesity are only a fraction of overall (indirect) costs to society (McCormick, 2007) which are due to loss of employment, production levels and premature pensions and deaths. Obesity is responsible for 2-8% of total health costs in Europe and other developed countries (WHO, 2007). Direct costs of obesity in Scotland were about  £175 million in 2007/8 and expected to double by 2030. The indirect costs were much higher (about  £457 million) and expected rise to  £0.9 billion- £3 billion by 2030 (Scottish Govt. report, 2010). In England, recent estimate of direct obesity-related costs to NHS is  £4.2 billion and this may double by 2050. Cost to the wider economy is in the region of  £16 billion, and will rise to  £50 billion per year by 2050 if left unchecked (Department of Health (DH) report, 2010). INEQUALITIES Although no clear relationship between socio-economic status (SES) in early life and childhood obesity (but confirmed a strong relationship with increased fatness in adulthood) was reported by Parsons et al.,(1999); a more recent systematic review by Shrewsbury and Wardle (2008) supports the view that overweight and obesity tend to be more prevalent among socio-economically disadvantaged children in developed countries. Similar patterns are shown in data from England (Stamatakis, Wardle and Cole, 2010; Law, 2007) and Scotland (Scottish Govt. report, 2010). However, trends vary within different ethnic populations as highlighted by Wang and Zhang (2006); a review by Caprio et al. (2008) who studied the influence of race, ethnicity and culture on obesity trends concluded higher prevalence in non-Caucasian populations in US. Although earlier reports (Wang, 2001) revealed that the burden of this problem was mainly in wealthier sections of the population in developing nations, recent reports (Lobstein, Baur and Uauy, 2004; Wang and Lobstein, 2006) indicate that prevalence is rising among the urban poor in these countries, possibly due to their exposure to Westernized diets overlapping with a history of undernutrition. The reasons for the differences in prevalence of childhood obesity among population groups are complex, involving race, ethnicity, genetics, physiology, culture, SES including parental education, environment, as well as interactions among these variables (Law et al.,2007; Caprio and Cali, 2008; Townsend and Ridler, 2009). ETIOPATHOGENESIS and COMPLICATIONS Kirk, Penney and McHugh (2010) argue the complexity of the obesogenic environment, which comprises of personal (e.g. diet and physical activity preferences; disability), physiological (e.g. genetics, race and ethnic, psychological, metabolic) and environmental factors (home, school, and community). Other contributory factors are influences in society (e.g., social and peer influences, food advertisements) and availability of and access to optimal health care. Although genetic factors can have an effect on individual predisposition (Wardle et al., 2008), perinatal and maternal factors explain rapidly rising global prevalence rates. Key perinatal factors for childhood obesity (Wojcik and Mayer-Davis (2010), cited in Freemark, 2010) are maternal overweight before, during and after pregnancy, smoking and bottle-feeding. The mothers dietary habits and level of physical activity are also significant. Decreased physical activity levels associated with sedentary recreation (video and computer games), mechanised transportation (less walking), and increasing urbanization (limited opportunity to physical activity) are all associated with increased risk of obesity (Trost et al. 2001; Gordon-Larsen, McMurray and Popkin, 2000). Children with disability are at a greater risk to develop obesity (Reinehr et al.,2010); factors include health concerns and restricted access to physical activity. Epstein et al. (2008) propose that television viewing encourages weight gain not only by decreasing physical activity, but also by increasing energy intake. In addition, television advertising could adversely affect dietary patterns throughout the day (Lewis and Hill, 1998). Psychosocial factors can influence dietary and physical activity behaviours that define energy balance. Children who suffer from neglect and depression are at increased risk for obesity during childhood and later in life (Johnson GJ et al.,2002; Pine DS et al.,2001).In contrast, social support from parents and others increases participation in physical activity of children and adolescents (Sallis, Prochaska, Taylor, 2000). There is evidence that breast milk in infancy may protect against overweight in childhood (Harder et al.,2005) while intake of foods with high glycemic index, sugary soft drinks and fast foods are associated with increased risk and prevalence of childhood obesity (Ludwig et al.,2001; French, 2001); however, long term trials are needed to corroborate this association. Also, eating out (Zoumas-Morse et al.,2001) appears to be an important contributory life style factor. Excessive fat in the diet is believed to cause weight gain (Jequier, 2001); though, this association is not consistently shown in epidemiological studies (Atkin L-M Davies, 2000; Troiano,2000). Lustig (2006) proposes that the relationship between changes in the environment and neuroendocrinology of human energy balance is complex. The author explains that behaviours of increased caloric intake and decreased energy expenditure are secondary to obligate weight gain that is due to associated hyperinsulinemia, leptin antagonism and interference with normal satiety. Childhood obesity is a multisystem disease with potentially serious complications. Several studies suggest that childhood overweight/obesity is associated with increased risk of mortality in adult life (Gunnell,1998; Dietz,1998). Young-Hyman et al. (2001) have documented cardiovascular risk factors along with insulin resistance in children as young as five years old. The rising prevalence of type 2 diabetes in obese children is worrying in view of the vascular complications (heart disease, stroke, limb amputation, kidney failure, blindness) (Ludwig and Ebbeling,2001). These risks appear to be higher in non-Caucasians (Goran, Ball and Cruz,2000). According to Strauss, (2000) adverse psychosocial effects are more severe in white girls. Treatment Effective intervention is essential because obese children are likely to face substantial health risks as they mature (Cali and Caprio, 2008). Further, as healthcare costs of this problem are rising (Wang and Dietz, 2002); intervention is required to prevent morbidity in adulthood while effective tools for primary prevention are developed. Spear et al. (2007) reviewed the evidence about the treatment options in primary care, community, and tertiary care settings and proposed a comprehensive 4-step approach for weight management. Uli, Sundarajan and Cuttler (2008) support a similar strategy. Several reviews of lifestyle (i.e. dietary, physical activity and/or behavioural therapy) interventions for treating childhood obesity (Oude- Luttikhuis et al.,2008; Wilfley et al., 2007) have concluded that family based combined behavioural and lifestyle interventions can produce significant reduction in overweight in children and adolescents. Although Golan and Crow (2004) suggested that targeting exclusively parents for change was superior to targeting only children for change, behavioural approaches involving both parents and children in the framework of a combined lifestyle intervention appear to be more effective (Wilfley et al. 2007; Epstein 1994; Bronwell, Kelman and Stunkard 1983). Moreover, intensive lifestyle intervention (with daily exercise, mandatory caloric restriction, multiple clinic visits and counselling sessions) appears to be more successful (Nemet at al. 2005) than standard lifestyle intervention (Epstein and Wing 1980). There is no consistent evidence to show that decreasing sedentary behaviour by reducing television viewing is effective in weight reduction (Dennison et al. 2004; Gortmaker et al. 1999). However, limiting TV food advertising to children appears to be a useful cost-effective population-based intervention (Magnus et al. 2009). In obese adolescents, treatment with orlistat or sibutramine as adjunct to lifestyle intervention is prescribed sometimes. However, these drugs can have significant side effects and this approach needs close monitoring and follow-up (Freemark, 2007). Morbidly obese adolescents can benefit from sizeable weight loss following bariatric surgery but with potential serious complications (Lawson et al., 2006; Uli et al.,2008). This necessitates close follow-up and dedication to a specialized dietary regimen (Shen, Dugay and Rajaram, 2004) for successful results. Evidence base of school-based interventions: Systematic reviews of random controlled trials (RCT) by Reilly and McDowell (2003) and Bluford, Sherry and Scanlon (2007) did not find sufficient evidence base for interventions to prevent childhood obesity and recommended further research. In contrast, Thomas et al. (2004) put forward a more positive conclusion in their review. Similarly, Flynn et al. (2006) and Doak et al. (2006) reported favourable outcomes in nearly all trials they reviewed. Interestingly, in an analysis of school-based programs, authors from National Institute for Health and Clinical Excellence (NICE), UK (2006) indicated that the evidence does not convincingly support the multidisciplinary whole school approach promoted by UK National Healthy Schools Program. Nonetheless, Connelly, Duaso and Butler (2007) in their review of RCTs have supported a decisive role for obligatory provision of aerobic physical activity in schools coupled with nutritional education and skills training. Finally, Kropski, Keckley and Jensens review (2008) concludes that although evidence is limited, schools play an important role in prevention strategies and directing different techniques at boys and girls may have more impact. HEALTH PROMOTION MODELS RELATED TO PREVENTION OF CHILDHOOD OBESITY Knowledge-Attitude-Behaviour model proposes that as knowledge accumulates, changes in attitude are set off resulting in gradual change in behaviour (Baranowski 1999). The model assumes that a person is logical by instinct. However, evidence shows that generally people in a variety of circumstances do not act logically (Shafir and LeBeouf, 2002). A common application of this model to promote change is providing health and nutritional information within school syllabi. Gaining knowledge may help to set goals and boost self-confidence but has not been shown to cause change in behaviour (Schnoll and Zimmermann, 2001) or to change in physical activity behaviour (Rimal, 2001) except perhaps in specific right people (Wang and Biddle 2001). Besides, there is no evidence that interventions based only on education strategies will change behaviour (Contento et al.,1995). According to Behaviour Learning Theory (BLT), when a specific stimulus elicits a desired behaviour, there is increased likelihood of that behaviour recurring if that behaviour is reinforced (Skinner,1938 as cited in Baranowski et al.,2003). A modern version of BLT, the Behavioural Economics model (Epstein and Salaens,1999) suggests behaviour is the result of benefits and costs where benefits are reinforcers. Obese people find food more reinforcing than others do whereas physical activity has greater reinforcing value among non-obese people. In addition, preference for a specific physical activity declines when the distance to that activity increases which reduces the reinforcing value of that activity (Raynor, Coleman and Epstein, 1998). Thus, obese people are more likely to find behaviours that lead to obesity more reinforcing. Saelens and Epstein (1998) applied the model successfully in obtaining increased physical activity. However, application of reinforcers on controlling behaviour is challenging and can be beyond the ability of many parents. The Health Belief Model explains the utility of health services. It has been widely applied to health-related behaviours (Janz, Champion and Strecher, 2002). The model describes health actions through the interaction of sets of beliefs: perceived susceptibility, perceived seriousness perceived benefits and disadvantages and cues to action. A meta-analysis study by Witte and Allan (2000) of fear-based communications revealed that they could induce behavioural change by affecting individuals perception of threat. However, children and adolescents often tend to perceive themselves as invincible, thus the concept of fear, threat and perceived risk and susceptibility are not useful in this age group. HBM may become more relevant if people perceive obesity as a serious threat waiting to happen to them (Baranowski, 2003). Social Cognitive Theory (SCT) proposes (Bandura 1999) that behaviour is a function of continuous mutual interaction between the environment and the person. The theory assumes that people generally strive for positive outcomes and evade negative ones by changing their behaviours by using self-control. Programs based on SCT have resulted in some changes as reported in a review by Sharma (2006) of school-based interventions for preventing childhood obesity where SCT was the most popular intervention tool. However, the theory lacks predictability for understanding childrens behaviour that is related to food and activityit could be that the concepts are too complex for children (Baranowski, Cullen and Baranowski,1999). Furthermore, children may not be expected to or capable of sufficient self-control over their diet and physical activity. Environmental variables like parenting and availability of food and physical equipment may be more beneficial (Cullen et al.,2003). Theory of Reasoned Action (TRA) and Theory of Planned Behaviour (TPB): To explain the relation between attitudes and behaviour (Ajzen and Fishbein,1975 in Baranowski et al.,2003) proposed TRA and said that people are more prone to perform a specific behaviour when they have the intention to perform it. The theory has many limitations one is that presence or absence of choice can influence behaviour e.g. unable to perform the intention to buy healthy food due to its unavailability in the local store. Ajzen and Madden (1986) modified TRA to TPB, which emphasises that perceived behavioural control influences intention. Goding and Koks review (1996) argued that the efficiency of the theory varies between health-related behaviour categories. TPB model has been applied to childhood obesity prevention programs with results showing both good (Andrews, Silk and Eneli, 2010) and mixed (Fila and Smith, 2006) predictability. The Transtheoretical model (T) proposes that health behaviour change progresses through six stages of change: pre-contemplation, contemplation, preparation, action, maintenance, and termination and describes 10 processes that enable this change (Prochaska et al.,1992). The model has been successfully applied in addictive disorders but has limitations when applied in the treatment of eating and weight disorders (Wilson and Schlam, 2004). T has been applied to obesity with studies reporting both good (Sarkin et al., 2001) and poor predictability (Macqueen, Brynes and Frost, 2002 in Wilson and Schlam, 2004). The complex etio-pathogenesis of childhood obesity suggests that Social Ecological (SE) Models may generate creative and lasting solutions (Huang and Glass, 2008). The SE model initiated by Bronfenbrenner (1977) and subsequently developed for understanding obesity by Davison and Birch (2001) and Story et al., (2008) proposes that individuals contribute their cognitions, skills and behaviours, lifestyle, biology and demographics, while surrounded in other circles representing the social, physical and macro-level environments to which they are exposed. Swinburn, Egger and Raza (1999) have described the ANGELO (analysis grid for environments linked to obesity) framework which is an ecological model for understanding environments that are obesogenic. Figure 1. The IOTF model is a SE model and describes societal policies and processes with direct and indirect influences on body weight (Kumanyika et al.,2002) as shown here in Figure 1(above). An ecological approach is also the basis of the Canadian model, Child Health Ecological Surveillance System (CHESS). As illustrated in Appendix 4, it demonstrates a local approach to tackle childhood obesity and has possible global implications (Plotnikoff, 2010). Global, regional and national prevention strategies As part of the response to fight the childhood obesity epidemic, WHO (2004) developed the Global Strategy for Diet, Physical Activity and Health (DPAS) and produced a range of tools to assist Member States and stakeholders to implement DPAS. It emphasised that National plans should have achievable short-term and intermediate goals. A schematic model developed for WHO by Sacks, Swinburn and Lawrence (2009) for implementation and monitoring of DPAS provides the basis for a framework for action and explains how supportive environments, policies and programmes can influence behaviour change in a population and have lasting environmental, social, health and economic benefits. The monitoring and evaluation component provides the foundation for promotion, policy development and action. Figure 2: Implementation framework for the Global Strategy on Diet, Physical Activity and Health. The model emphasises the need of right mix of upstream (socio-ecological) approaches to shape the economic, social and physical (built and natural) environments, midstream ( lifestyle) approaches to directly influence behaviour (reducing energy intake and increasing physical activity), and downstream (health services) approaches to support health services and clinical interventions (Sacks, Swinburn and Lawrence, 2008 in WHO report, 2009). According to WHO (2009), population-based prevention strategies developed in the context of a social determinants-of-health approach and implemented both at the national level and locally in school and community-based programmes will help to change the social norm by encouraging healthy behaviours. Furthermore, transferring the responsibility of tackling health risks from the individual to decision-makers will help to combat associated socio-economic inequalities. In addition, strategies will need coordinated action by multiple stakeholders and effective leadership for success. Surveillance tools for growth assessment recommended by WHO are Child Growth Standards (WHO Reference, 2007) and the Global School-based Student Health Survey (GSHS) (WHO, 2009). Key challenges of population based strategies identified by WHO are increasing globalization of food systems that have created economic and social drivers of obesity through changes in food supply and peoples diets, worsening socioeconomic inequalities and tackling obesity in children with physical and/ or mental disabilities. Other important hurdles are poorly designed urbanisation and achieving cost-effectiveness. In this regard, combined approaches that address multiple determinants can improve efficiency of intervention programmes according to a model-based analysis by OECD and WHO (Sassi 2009 in WHO report 2009). The Ottawa Charter for Health Promotion (WHO 1986) recommends that global prevention strategies should work at multiple settings (e.g. schools, after-school programmes, homes and communities and clinical settings) and use the correct mix of approaches for a given situation along with concern for country- and community-specific factors, such as availability of resources and/or socioeconomic disparities. It emphasises that such strategies must identify and include at-risk groups, set priorities and realistic targets and engage with all stakeholders in a transparent manner. The public should have access to information on partnerships including potential conflicts of interest. Successful implementation and sustenance of such strategies depends on long-term planning, budgeting and identifying cost-effective interventions such as the ACE-Obesity project (Carter et al., 2009). It is also important to dissociate private sector funding from projects that set direction and techniques of such programs by adopting novel funding strategies. The IOTF (2007) have developed in consultation with WHO a set of (Sydney) principles that define the commercial promotions of foods and beverages to children and guide action on changing marketing practices them. The principles aim to ensure a degree of protection for children against obesogenic foods and beverages. The European Union (EU) Member States have adopted the European Charter on Counteracting Obesity (2006), which defines WHO policies and action areas at the local, regional, national and international levels for all interested parties in government and private sectors (e.g. food manufacturers, advertisers and traders) and also organizations of professionals (providers) and consumers (users). Policy strategies emphasise the need to identify and focus on at-risk population groups, set realistic goals, and use efficiently coordinated multiple settings and approaches. They also stress the need for research into all aspects of treatment and prevention methods and develop creative sustainable funding (WHO Europe, 2007). In UK (England), to encourage individual behavioural change, the strategy Healthy Weight, Healthy Lives: A Cross-Government Strategy (DH, 2008) has been developed with emphasis on healthy growth and development of children, promotion of healthier food choices and bringing physical activity into peoples lives by building healthy towns on the EPODE model ( Borys 2006). It also aims to provide personalised advice and support and create incentives to be healthy. Policy drivers include national policy changes (e.g. increased support for monitoring of growth, promotion of breast feeding, bans on unhealthy food advertisements, social marketing campaigns) and changes to the food supply (e.g. development of a healthy food code, front-of-pack labelling, limits on fast-food restaurants near schools and parks, increased supply of fresh fruit and vegetables to stores in deprived areas). Change4Life is the marketing arm of the Governments strategy to stress on prevention through healthier habits from early life (DH, 2009). Other strategies are development of a national physical activity plan in part tied to the 2012 Olympics with the purpose of improving built environments and support more weight management services. The national Government leads the project and provides resources for local authorities, National Health Service (NHS), and community care partnerships. Government agencies and their partners coordinate to raise funds and integrate projects into existing strategies and programmes for cost-effectiveness. Long-term goals include developing a national dialogue on societys response to the epidemic of obesity, provide more support and guidance for PCTs and local authorities and build up skills and capabilities of staff, set aside extra resources and while demonstrating good governance and clear accountability. In Scotland, the Government and Convention of Scottish Local Authorities (COSLA) have developed a Route Map for decision-makers in government to work with their partners, NHS and businesses to develop and deliver lasting solutions to prevent overweight and obesity (Scottish 2010). The Government has targets to reduce the rate of increase in the proportion of children with unhealthy BMI by 2018 but none yet for obesity or weight management. The aim is to reduce energy consumption, increase physical activity, minimise sedentary behaviour, and create positive health behaviour through early life interventions and building healthier work place environments. Policy drivers to manage obesity include HEAT (health, efficiency, access and access target) which measures achievement rates for intervention programmes, Counterweight which is a second-level program to support people who need management of their weight, and Scottish Enhanced Services that provides childhood obesity services in primary and community care settings. To prevent obesity, the Government has developed several initiatives in a framework Lets Make Scotland More Active which is for promoting increased physical activity. Policies to help build healthier lifestyle are the National Food and Drink Policy Recipe for Success, eight Healthy Weight Communities programmes nation-wide, and Seven Smarter Choices Smarter Places to study travel behaviours of communities and their potential to adopt healthier choices. Take Life On is a national social marketing drive that aims to improve diet and fitness of communities and Beyond the School Gate and Scotlands Healthy Weight Outcomes Framework will provide guidance to help create health-promoting communities. In addition, there are several national programs directed to a Greener, Healthier, Smarter, Safer and Stronger Scotland which are likely to have indirect contribution to tackle overweight and obesity. CONCLUSION: The essay emphasises the rapidly increasing burden of childhood obesity with associated population profile changes and increasing social inequalities. It explains the complex multifaceted and interlinked causal pathways that form the obesogenic environment. The author has described community and school-based obesity intervention and prevention programmes and explored the role of research protocols in gathering evidence for such interventions and their usefulness. Various prevention strategies and interventions (singly and in combination) that are in practice and the settings and conditions in which they may be effective are reviewed and compared. Existing global, regional and national prevention and implementation strategies and their need to tackle upstream influences to fight childhood obesity are explained. The present evidence for effective treatment and prevention of childhood obesity is not consistent. It is very difficult to attain significant weight on a long term basis in spite of strenuous efforts it could be that present prescriptions for diet and exercise are not as effective as they need to be; in addition, the adversities in the environment can overwhelm the beneficial effects of techniques used in current intervention techniques. Further research is required to identify realistic options for treatment and best practice procedures for public health policies that are cost-effective, culturally sensitive, deal with upstream influences and address population inequalities. Although numerous school and community based programs are having an impact, there is a need for evidence to evaluate effective social interventions so that social policies direct healthy lifestyle approaches. From the review of available evidence, the author has learnt that policymakers and professiona