CANCER PREVENTION INSTITUTE OF CANADA

Last updated: 15-Jan-2007

Risk Factor Interventions

This section is part of a broader set of initiatives to support the development of province-wide strategies for chronic disease prevention, with a particular focus on heart disease, cancer, chronic respiratory disease, and diabetes.

In spring of 2004 the B.C. Healthy Living Alliance took on the task of developing provincial advocacy targets for the reduction of four major risk factors by the year 2010. This is consistent with the mandate of the Alliance, namely “To improve the health of British Columbians through leadership that enhances collaborative action to promote physical activity, healthy eating and living smoke-free.”

An initial step in this process was the preparation of a document which provided a detailed examination of the four risk factors, namely, smoking, unhealthy eating, physical inactivity, and overweight, and their link to chronic disease. This report, 2010 Target Setting for Risk Factors for Chronic Diseases: Background Document for Consultation, also reviewed current risk behaviour at the provincial, health authority, and health service delivery area.

A second step was to develop consensus on provincial population-level targets for the four risk factors for 2010 – targets that take into account the variation in risk behaviour in communities across the province. Once targets had been established, a key question related to the achievement of those targets. Which interventions are effective at assisting in achieving the targets?

This section, derived from the report: “Risk Factor Interventions – An Overview of their Effectiveness”, represents the third step in this process; it is a comprehensive review of the effectiveness of interventions designed to impact selected risk factors. In this project we use the term ‘interventions’ in its broadest form, including specific programs, policy initiatives, advertising campaigns, and so on, plus more than one approach combined in comprehensive strategies.

In addition to the four major risk factors noted above, exposure to second-hand tobacco smoke, ultraviolet radiation, occupational and environmental carcinogens and infections have been added to this review.

Further work will use the information contained in this report to prioritize interventions (including an evaluation of cost effectiveness) and estimate the resources needed to implement the selected approaches in the British Columbia context. In addition, the potential benefits of achieving targets established for 2010 will be assessed.

Combining the Factors

Most risk factors do not exist in isolation. This is particularly the situation with smoking, unhealthy weight, unhealthy eating, and physical inactivity, which may exist in combination in the same individual.

There are several arguments for treating key risk factors in this report in an integrated manner. First, for each of the four risk factors it is demonstrable that they have a significant independent effect on mortality and morbidity; thus to make the most population health gains, sometimes the factors need to be addressed simultaneously or, at least, in a clearly structured sequence.

The four risk factors noted above are also related to one another to various degrees. One of the key relationships between factors is “overlap.” Although there are health impacts of, say, physical inactivity that are in fact independent of other factors, it is also clear that there are a large percentage of impacts that flow from the contribution of inactivity to obesity. Sedentary Canadians, for example, have a 44% higher rate of obesity than physically active Canadians; the effect on related disease rates would thus likely be a combination of the two factors.

The multiplicity of risk factors can extend in more than two dimensions. Just as activity and weight are linked, nutrition can be seen as closely related to both those factors. In fact, unhealthy weight, unhealthy eating and physical inactivity are so inextricably bound together as risk factors for the “metabolic syndrome” which is a precursor to type 2 diabetes and cardiovascular disease, that this report will treat them in an integrated way in a major section.

Smoking, though treated separately, must be brought in to the multi-factorial discussion. Most importantly, smoking heightens the negative health impacts of being obese. Smoking also demonstrates that risk factors sometimes move in opposite directions. The weight gain that can accompany smoking cessation, for example, should be addressed in any integrated risk factor policy.

Smoking also indirectly affects other factors such as obesity through the influence of decades of research and practice around effective interventions. The lessons derived from the “tobacco wars” will help to shape other aspects of this report.

A final consideration is that the process of targeting multiple risk factors increases the opportunity for collaboration between different stakeholders in the world of prevention and health promotion, and the possibility of focusing limited resources to achieve the greatest benefit. The fact that a short list of major risk factors relate to the same serious chronic diseases multiplies the potential for such initiatives.

Reviewing the Evidence

The plan in this section is to “summarize the summaries.” By the 1980s, leaders in medical research and healthcare had begun to realize that critical reviews were needed to put results from individual studies into an appropriate context. As well, the sheer volume of biomedical publishing requires the resources of expert meta-analysis and synthesis. There are an estimated 30,000 medical journals published annually.

All published studies are also not created equal. It is especially important to isolate high-quality research results in order to confidently propose “evidence-based” interventions. Expert reviews of related studies typically use a criteria grid to eliminate low-quality studies and weight the results of the remaining ones according to the scientific rigor of their research methodology. Appendix A contains an overview of the major review sources consulted in this report.

Organizing the Interventions

In the initial scan, the interventions in each major subsection will be organized into all or most of the following seven categories (as appropriate), which themselves are mostly driven by the setting where the intervention is implemented:

• Community-based Interventions
• Workplace-based Interventions
• School-based Interventions
• Home-based Interventions
• Clinical Interventions and Management
• Regulatory and Economic Interventions
• Comprehensive Strategies

In this taxonomy, mass media interventions will be classified under community-based interventions; regulatory and economic mechanisms, which certainly also affect whole communities, are separated out as interventions requiring the direct action of senior governments. Comprehensive strategies represent a combination of two or more of the other categories. Sometimes the term “comprehensive” is used loosely to mean “multi-component,” but this is a mistake, since every one of the categories includes projects which comprise multiple interventions.

No taxonomy of risk factor interventions is perfect, which is why so many have been proposed by different reviewers. For instance, there are local and senior government policy initiatives with specific targets (e.g., legislated smoking bans in schools or workplaces)) which will be included under the settings where they most apply.

The Social Context of Human Health

It has been very common in the past to treat risk factor control as a matter of individual behavioural choices and change. While this remains an important dimension of health promotion and disease prevention, increasing attention is being paid to the social dimensions of human life which may either support or impede healthy lifestyle decisions and impact the associated prevalence of disease. Three aspects of human existence which transcend individual behaviour will be woven into this report at different points, including:

• the socio-economic context
• the socio-environmental context
• the socio-cultural context

Many of the concepts under these headings overlap with the concerns of social ecology, namely, to consider social networks and supports systems, the historical context of people’s lives, cultural milieu (norms, values and expectations), and institutional interactions in the public (e.g., school) and private (e.g., workplace) sphere .[1]

Socio-Economic Context

Risk factors are influenced by socioeconomic factors, sometimes called the social determinants of health. A recent report for the Interior Health Authority described social determinants of health in the following way:
Social and economic exclusion is not a choice. People who are socially and economically excluded from society experience material deprivation, including barriers to jobs and education. They also tend to experience psychological stress and frequently adopt unhealthy behaviours as a means to cope with these stresses.[2]

This description combines three different, though interrelated, streams in the conceptualization and study of social determinants:[3]

Materialist: disadvantaged people are deprived of the material necessities for health; most of the research so far has focused on income inequalities, rather than, for example, access to education or employment.

Psychosocial: the way psychological stress and limited social support limits the ability to avoid behavioural risks.

Political: looks at systemic forces, including international, national and regional policies that increase poverty and unequal access to health resources.

Socio-Environmental Context

A socio-environmental approach is closely related to the social determinants of health, with the main difference being one of emphasis. While social determinants originally were derived through studies of individual-level socioeconomic measures, an environmental approach considers the impact that area-wide socioeconomic characteristics might have on the prevalence of risk factors.[4] Although the research is still relatively limited, the suggestion is that simply living in a deprived area may have an impact on behaviour not just because of the example and influence of more risky behaviour in the neighbourhood, but because of the unpleasant, unsafe environment where there are fewer opportunities for making healthy choices.[5]

Socio-Cultural Context

The third social context builds on the ideas that the cultural norms and expectations in a society can exert a powerful influence on behaviour.
Social denormalization is a related phenomenon which describes the point where attitudes match and reinforce behavioural change (which has been brought about by whatever means), so that the wide majority of a population has adopted a new dominant attitude, e.g., smoking in someone’s home without permission is unacceptable. This type of attitudinal shift is closely akin to the “diffusion of innovations” theory proposed by Rogers.[6] The theory allows for a stage of idea development or marketing where most people in a community have adopted an innovation.

The application of denormalization to risk factor reduction within a population is clear and appropriate. It represents a call to create long-term public health messageswithin society that eventually produce a sea-change in public sentiment, that in turn might be more effective than any other intervention in changing personal behaviour. This shift in social atmosphere has the advantage of being at least temporarily self-sustaining, i.e., with little or no additional public investment.

A Clinical Caveat

Although population health initiatives will be well-represented in this report, there also will be an emphasis on clinical interventions for both primordial and primary prevention. Although some question whether the limited reach of clinical approaches (compared to the efficiency of population-based interventions) should exclude them from priority consideration, the position of this report regarding increasing clinical capacity is justifiable. Apart from the strong evidence base indicating the effectiveness of clinical interventions for behaviour change and risk factor reduction (see below), there is the simple matter of appropriately supporting the change that motivated individuals who are at-risk want to make. It is hardly socially justifiable to stir up interest in health improvement at a population level, and then not adequately “catch” those who desire to do something about it and would benefit from intensive support measures.