Challenging Dogma - Fall 2009

Thursday, December 17, 2009

Health belief Model: losing a battle against obesity - Marina Tuzova

Health behaviors contribute to many of today’s public health problems. Studies in early 90s demonstrated that unhealthy behaviors are responsible for 40–60% of the deaths in the US (1). This issue is particularly important for the problem of child and adolescent obesity, which is the leading cause of disease development during adulthood in the US. Having a healthy diet and an active lifestyle are just two examples of the many health behaviors that have been shown to effectively reduce obesity in children. The question is how to introduce healthy behaviors to children and replace unhealthy habits.

There are health models used by sociologists to predict people’s health choices. A model that has been highly used historically is called the Health Belief Model.

The original Health Belief Model, introduced by Rosenstock (1966), was based on four constructs of the core beliefs of individuals based on their perceptions:

  • Perceived susceptibility (an individual's assessment of their risk of getting the condition);
  • Perceived severity (an individual's assessment of the seriousness of the condition, and its potential consequences);
  • Perceived barriers (an individual's assessment of the influences that facilitate or discourage adoption of the promoted behavior);
  • Perceived benefits (an individual's assessment of the positive consequences of adopting the behavior);

A variant of the model also includes the perceived costs of adhering to prescribed intervention as one of the core beliefs.

Constructs of mediating factors were later added to connect the various types of perceptions with the predicted health behavior:

  • Demographic variables (such as age, gender, ethnicity, occupation);
  • Socio-psychological variables (such as social economic status, personality, coping strategies);
  • Perceived efficacy (an individual's self-assessment of ability to successfully adopt the desired behavior);
  • Cues to action (external influences promoting the desired behavior, may include information provided or sought, reminders by powerful others, persuasive communications, and personal experiences);
  • Health motivation (whether an individual is driven to stick to a given health goal);
  • Perceived control (a measure of level of self-efficacy);
  • Perceived threat (whether the danger imposed by not undertaking a certain health action recommended is great);

The model attempts to predict the likelihood of the individual’s concern to undertake a recommended health action (such as preventive and curative health actions). The Health Belief Model relates largely to the cognitive factors predisposing a person to a health behavior, concluding with the belief in one's self-efficacy for the behavior. The model leaves much still to be explained by factors enabling and reinforcing one's behavior, and these factors become increasingly important when the model is used to explain and predict more complex lifestyle behaviors that needs to be maintained over a lifetime.

The Health Belief Model (Rosenstock 1966, revised by Becker et al):

The health belief model emphasises only individual cognitions, not the social context of these cognitions. It is assumed that behaviours result from a rational weighing of the potential costs and benefits of the behaviour. A systematic, quantitative review of studies that had applied the Health Belief Model among adults into the late 1980s found it lacking consistent predictive power for many behaviors, probably because its scope is limited to predisposing factors. Nevertheless, the health belief model continued to be the most frequently applied model in published descriptions of programs and studies in health education and health behavior in the early 1990s. It remains, however, a guide to practitioners in planning the communication component of health education programs (2).

Health Belief Model (HBM) was used by public health professionals to replace unhealthy food choices in children and adolescents with healthy food choices, but it failed. The USA is facing an obesity epidemic. Obesity is a major cause of morbidity and mortality and is associated with high medical expenditures. It has been suggested that obesity prevention could result in cost savings (3). An underlying problem in developing a comprehensive strategy to address the rise in childhood obesity is that the attitude towards the treatment of obesity has historically focused exclusively on the behaviors of the obese individual (which is the baseline for HBM). Obesity treatments for adults consist of behavioral or medical interventions designed to change one person at a time. Obese children are treated the same way, with specific psychological, behavioral and medical treatments aimed at individual children and their families. A recent decision of several school systems to mail home letters to parents of overweight children to alert them to their child’s poor health status, exemplifies the attitude that parents and children are responsible for solving the problem of childhood obesity (4). Besides not working, the strategy was harmful: it created stigmatization of obese and overweight children, which means that no interventions will work later on. After investing over $1.2 billion in the government's "war on obesity," the National Institutes of Health (NIH) has released the final version of its strategy to combat obesity in America. The Strategic Plan for NIH Obesity Research represents a multi-dimensional research agenda to enhance both the development of new research and the coordination of obesity research, according to NIH Director Elias M. Zerhouni, M.D. (5). Would it do any good? The plan was still based on the old conservative behavioral models including HBM, which do not work as good predictors of human irrational behavior. The complexity of the obesity epidemic requires the cooperation of key stakeholders in this effort, and not only stakeholders, but also society in general. No one sector - academia, government, industry, or health care - has been successful in combating this disease to date. On March 2004, The Harvard Medical School Division of Nutrition hosted the symposium “Science-Based Solutions to Obesity: What is the Role of Academia, Government, Industry, and Health care?” as a platform to address the role of these stakeholders, both individually and collectively, in combating the nation’s epidemic of obesity. The discussion included the following: the science of obesity-related topics such as genetics, weight loss, portion size, energy density, and behavior; the need for more aggressive government policies; industry’s role in using research and development capabilities to promote healthier, portion-controlled products; and how to translate nutrition information from medical doctors to patients (6).

The behavior was discussed briefly and again only classic behavioral approaches were considered. No wonder the attempts to fight obesity keep failing. There are some human phenomena which seem to be the result of individual actions and personal decisions. But these phenomena are usually as much a result of social factors as of psychological ones. Let me give a simple example. There are four commonly suggested public health strategies to combat childhood obesity:

  • Limiting television viewing;
  • Encouraging daily physical activity;
  • Increasing fruit and vegetable intake;
  • Increasing water consumption instead of soda;

The study (7) examined the extent to which selected social theory constructs can predict these four behaviors in upper elementary school children. Even though the authors reported some success, the results of this study do not look convincing, the children are becoming more and more obese, the population in general is becoming more and more ill, and the Government keeps spending more and more money to combat the consequences, but not to implement the preventive measures. The conclusion is simple: considering only individual cognitions will never help to erase the problem. We are living in the society, and there are some social stereotypes, which we should fight first to be able to overcome.

Theories of the development of obesity stereotypes cannot easily explain the stigma associated with being obese (8). The societal message about being fat in the 21st Century is clear: it is bad to be fat. But why is it bad? Clearly, there are serious medical consequences of obesity. The medical issues, however, are sometimes used to cloud the clear bias and discrimination against obese people. Obese people are not discriminated against because they are medically compromised. They are stigmatized because their obesity is viewed as a reflection of poor character. Common stereotypes associated with obese people include attitudes that they are lazy, incompetent, lacking in self-discipline, self-indulgent and emotionally unhealthful (4). Evidence that important similarities exist between the symptoms of obesity and contagious illnesses were presented in the study (9), where young children have "theories" of illnesses, and obesity stereotypes are among the earliest that children develop, led to the hypothesis that children would find beverages purportedly created by obese children less tasteful and more memorable than beverages created by average weight children. Taste ratings were lower, ratings of the chances of feeling sick were higher, and memory was superior for obese-created drinks than for average-created drinks. Finally, children often created the false memory that the story character was an obese beverage creator. The rationality of children's responses was questionable; the roles of contagion and magical beliefs were questionable even more (9).

What do we know about how children eat?

Ø Biological factors:

  • Children have a preference for sweets and salt;
  • Children fear new and unfamiliar foods;
  • Children are predisposed to learn to prefer energy-dense foods;
  • Children can effectively self-regulate when provided with healthful food choices;

Ø Parenting factors:

  • Children need approximately 10 exposures to new foods to accept them;
  • Children can learn to prefer new foods as they become increasingly familiar;
  • Children are more likely to eat foods that teachers, parents and peers are eating;
  • Children will overeat when they are rewarded for eating;
  • Children desire palatable foods that they can see but are forbidden to have;

Ø What do we need to learn?

  • Are some children biologically vulnerable to difficulty self-regulating food intake?
  • Which comes first – parental restriction or childhood dis-inhibition?
  • Can children self-regulate intake when surrounded by palatable high calorie foods?
  • How does advertising affect children’s food preferences and intake?
  • How can parents encourage healthful eating without being perceived as withholding? (4).

Of course, the obesity is a disease with complex nature and deep social roots. We cannot rely on rational behavioral theories to explain why obese people do not choose the simple four healthy habits to lose the weight, to become healthy and to gain more self-esteem. The HBM does not explain the deep damage caused by stigma on obese kids and how to fight it. And it does not imply even simple social factors, like eating habits in the surrounded family, unhealthy school snacks, exposure to constant fast foods and soft drinks advertisements. We have to change the whole microenvironment to be able to change someone’s perception of what is good and what is bad. There should be examples and opinions from peers and family to make sure the healthy habit is naturally acquired from early childhood, because an obesity rate of 42.2% in our children is unacceptable. Is it possible? Well, it is when the healthy foods and physical activity are highly accessible and not very expensive.

Here are some proposed societal level interventions:

Ø Change the food environment:

  • Remove non-nutritive snack foods and sugared drinks from schools;
  • Discourage adults from feeding poor foods to children;
  • Pressure restaurants to provide ‘kids meals’ that are economical and nutritious;
  • Change the role of the food industry;
  • Pressure the food industry to stop developing and advertising nutritionally poor ‘children’s foods;
  • Encourage the food industry to create healthful and affordable food products for children;

Ø Change the view of obesity

  • Add weight to the list of personal characteristics that are unacceptable reasons for discrimination;
  • Include weight tolerance when we teach tolerance of other individual differences;
  • Educate the public on how to accept obese people while fighting the diseases linked to obesity (4).

The locus of responsibility for childhood obesity needs to shift away from individuals and towards the environment. It is a social disease and the society should share responsibility to fight it. There is increasing interest from both policy-makers and researchers in the social and environmental factors, which influence obesity. These factors include the physical environment, social values, technology and the economy. Interventions that aim to change social and environmental factors in order to reduce obesity may include taxes or subsidies to encourage healthy eating or physical activity, extra provision of sporting facilities, efforts to improve safety and accessibility of walking and cycling or play areas or attempting to influence the social meanings and values attached to weight, food or physical activity. However, there is still not a robust understanding of the extent to which social and environmental interventions work to reduce obesity (10).

Recently, Drs. Ken Resnicow and Roger Vaughan published a thought-provoking paper in the International Journal of Behavioral Nutrition and Physical Activity (IJBNPA). They argued that the most often used social-cognition theories in behavioral nutrition and physical activity are of limited use. These models described behavior change as a linear event, while Resnicow and Vaughan postulated that behavior change is more likely to occur in quantum leaps that are impossible to predict. They introduced Chaos Theory into the behavioral nutrition and physical activity domain as a more valid framework to study the complex process of health behavior change. Prof. Tom Baranowski provided a separate commentary on Resnicow and Vaughan's paper, which was also published recently in the IJBNPA (11). He recognized that there was a limited success of social cognition models, and poor application of these models and more research should be done to test these models, especially to further test the quantum and chaotic character of health behavior change. However, if such research supports the chaotic and quantum nature of health behavior change, the implications for behavioral nutrition and physical activity interventions will be highly limited, because even if behavior change is quantum rather than linear, the social cognition models are still relevant to inform interventions to promote quantum leaps in behavior change (12).

Proposed variables and applicable interventions (12):

References:

1. L.B. Trifiletti, A.C. Gielen, D.A. Sleet, K. Hopkins. Behavioral and social sciences theories and models: are they used in unintentional injury prevention research? Health Education Research; Vol.20, No.3, 2005, pp. 298–307.

2. Green L.W. Health Belief model. http://www.enotes.com/public-health-encyclopedia/health-belief-model

3. P.H.M. van Baal1, J.J. Polder, G.A. de Wit, R.T. Hoogenveen1, T. L. Feenstra, H.C. Boshuizen1, P.M. Engelfriet1, W.B.F. Brouwer. Lifetime medical costs of obesity: prevention - no cure for increasing health expenditure. PLoS Medicine, February 2008, Volume 5 (2), pp. 0242-0249.

4. M. B. Schwartz and R. Puhl. Childhood obesity: a societal problem to solve.

Obesity Reviews, 2003, Vol. 4, pp. 1-17.

5. R. Longley. NIH has strategy to fight U.S. obesity. Plan aims for treatment and prevention. www.about.com

6. G.L. Blackburn, W.A. Walker. Science-based solutions to obesity: what are the roles of academia, government, industry, and health care?

Am J Clin Nutr 2005; 82(suppl); pp. 207–210.

7. J. Murnan, P. M. Sharma, D. Lin. Predicting childhood obesity prevention behaviors using social cognitive theory: children in China. Int’l. Quarterly of Community Health Education; Vol. 26(1); pp. 73-84; 2006-2007.

8. T. Anesbury, M. Tiggemann. An attempt to reduce negative stereotyping of obesity in children by changing controllability beliefs. Health Education Research, Vol. 15, No.2, 2000, pp.145-152.

9. P.A Klaczynski. There's something about obesity: Culture, contagion, rationality, and children's responses to drinks "created" by obese children. Journal of experimental child psychology. 2008, vol. 99, No.1, pp. 58-74.

10. Woodman J, Lorenc T, Harden A, Oakley A. Social and environmental interventions to reduce childhood obesity: a systematic map of reviews. 2008; London: EPPI-Centre, Social Science Research Unit, Institute of Education, University of London.

11. T. Baranowski. Crisis and chaos in behavioral nutrition and physical activity. Int. J. Behav Nutr Phys Act, 2006, 3:27; 10.1186/1479-5868.

12. J. Brug. Order is needed to promote linear or quantum changes in nutrition and physical activity behaviors: a reaction to 'A chaotic view of behavior change' by Resnicow and Vaughan. Int J. Behav Nutr and Phys Act, 2006, No3: 29; 10.1186/1479-5868.

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