Cardiovascular Disease, Diabetes, High Blood Pressure, Cholesterol, and Bodyweight
The disease burdens from CVD, diabetes, and related conditions of high blood pressure, high cholesterol, and excessive bodyweight are increasing worldwide.1 Once considered diseases of industrialized countries or of the affluent in developing countries, they are now recognized as global problems.
In 2001, CVD became the world's leading cause of death and now accounts for 28 percent of all deaths worldwide, with 80 percent of the burden in low- and middle-income countries. Most of that burden falls in Asia and Eastern Europe because of the large populations in these regions and the high incidence of coronary artery disease in Eastern Europe and Central Asia. Diabetes is also on the rise around the world, reaching a prevalence of 5.1 percent in 2003. The prevalence of diabetes is greatest in high-income countries at 7.8 percent, and in developing regions ranges from a low of 2.4 percent in Sub-Saharan Africa to a high of 7.6 percent in Eastern Europe and Central Asia. Despite the higher prevalence of diabetes in high-income countries, the majority of the disease burden from diabetes, more than 70 percent, is in the developing regions because of their larger populations.2
"Despite the higher prevalence of diabetes in high-income countries, the majority of the disease burden from diabetes, more than 70 percent, is in the developing regions because of their larger populations."
Another way of looking at the burden of CVD, diabetes, and related conditions is to classify them by risk factor. The World Health Report 2002 (WHO 2002) estimated that globally, 7.1 million deaths could be attributed to high blood pressure, 4.4 million deaths to high cholesterol, and 2.6 million deaths to excessive weight. Excessive weight is a growing problem in almost every country, even the poorest. It is increasing so rapidly that in middle-income countries the disease burden associated with having a body mass index greater than 25 is now equal to or greater than the disease burden resulting from undernutrition.
These diseases are not inevitable consequences of modern life. Low rates can be achieved with moderate changes in lifestyles that are fully compatible with life in the 21st century. Nevertheless, the requisite changes in smoking habits, physical activity, and diet may not be easy and will require support and encouragement through investments in education, changes in food policies, and sometimes even changes in urban infrastructure. Whereas the required behavioral changes are the same everywhere, the ways to achieve them will necessarily vary across countries and regions, with different approaches corresponding to cultural, social, and economic features.
Lifestyle Interventions
The key risk factors for CVD and diabetes—obesity, physical inactivity, and unhealthy diets—require interventions to change unhealthy lifestyles. These changes are most likely to occur with implementation of a coordinated range of interventions to encourage individuals to maintain a healthy weight, participate in daily physical activity, and consume a healthy diet. A healthy diet replaces saturated and trans fat with unsaturated fat; increases consumption of fruits, vegetables, and whole grains; and limits sodium intake and excessive calories from any source, but especially from sugar-based beverages.
". . . in middle-income countries the disease burden associated with . . . a body mass index greater than 25 is now equal to or greater than the disease burden . . . from undernutrition."
Education is key to implementing such changes. It appears to be more effective when provided through multiple methods and sites, such as schools, workplaces, mass media, and health centers. Educational messages are also more effective if they are reinforced by action. Schools, for example, should provide not only curricula on good nutrition but also healthy meals; worksites should not only inform workers about the role of physical activity but facilitate the use of nonmotorized transportation.
"Because using an automobile is twice as costly in Europe as in the United States, Europeans walk or bicycle more and use their cars approximately 50 percent less than Americans."
Urban design and transportation policy are other key elements of lifestyle interventions. People can be encouraged to increase their physical activity by using public and nonmotorized transport, especially walking and bicycling. Although not normally considered an instrument for improving health, national transportation policies can strongly influence automobile use and dependency. Low taxes on gasoline, free parking, and wide street design encourage the use of automobiles (as in the United States), while narrow streets, limited parking, and high gasoline costs discourage their use (as in Western Europe). Because using an automobile is twice as costly in Europe as in the United States, Europeans walk or bicycle more and use their cars approximately 50 percent less than Americans. The same trends in public policy are played out in low- and middle-income countries. Singapore has been a leader in discouraging private automobile use and encouraging use of public transport, walking, or bicycling. By contrast, China has explicitly encouraged families to buy automobiles by lowering taxes, simplifying registration procedures, and allowing foreign financing.
Food policy is another important area for encouraging lifestyle change. Policy tools include how food is processed by fortifying foods with micronutrients and limiting advertising for unhealthy foods. One of the most effective ways to improve diets is to regulate or provide incentives for food manufacturers to replace unhealthy ingredients or products with healthier ones. Changes in types of fats, for example, can be almost imperceptible to consumers and relatively inexpensive. Many European manufacturers have greatly reduced foods' trans-fatty acid content by changing production methods. In this way, the Netherlands reduced the trans fat content of the food supply from about 6 percent of the energy content to approximately 1 percent in a single decade. In Mauritius, government policies replaced commonly used palm oils for cooking with soybean oil, which reduced the intake of fatty acids and lowered serum cholesterol levels. Other easily targeted changes in food processing include reducing salt and fortifying foods with micronutrients such as vitamin A, vitamin B12, iodine, iron, and folic acid.
". . . the Netherlands reduced the trans fat content of the food supply from about 6 percent of the energy content to approximately 1 percent in a single decade."
Experience has provided some lessons for implementing successful lifestyle interventions across populations:
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Interventions should be long term with multiyear time frames.
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Credible agencies should be responsible for such interventions.
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Collaboration between the health sector, other government agencies, schools, workplaces, and the voluntary sector is important.
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Cooperation with the food industry is essential to ensure the availability of reasonably priced healthier food options with food labeling that presents relevant information in a clear, reliable, and standardized way.
Several lines of evidence indicate that most coronary artery disease, stroke, and diabetes and some cancers can be prevented or delayed by realistic changes in diet and lifestyle. One line of evidence is based on declines in coronary artery disease in countries that have implemented preventive programs. A dramatic example is that of Finland, which had the highest rates of CVD in the world, and where a comprehensive program focused on diet and lifestyle modification reduced the mortality rate by approximately 75 percent between 1972 and 1992 (box 5.1).
[Box 5.1]
DCP2 estimates the cost-effectiveness of several of these interventions. Replacing saturated fat with monounsaturated fat in manufactured products, accompanied by a community media campaign, can reduce coronary artery disease events by 4 percent. The total cost of these changes would range from US$1.80 to US$4.50 per person per year depending on the region. The incremental cost-effectiveness ratio would range from US$1,865 per DALY averted in South Asia to US$4,012 per DALY averted in the Middle East and North Africa.
Replacing the 2 percent of energy that comes from trans fat with polyunsaturated fat would reduce CVD by 7 to 40 percent and would also reduce type 2 diabetes. The effect would vary by region. Trans fat consumption is already low in China, so replacing it with polyunsaturated fat would not avert as much disease as in South Asia, where commonly used cooking fats have an extremely high trans fat content. Because partially hydrogenated fat could be eliminated or significantly reduced by voluntary industry action as done in the Netherlands or regulation as in Denmark, this intervention requires no consumer education, and the cost amounts to no more than US$0.50 per person per year. The cost-effectiveness ratio for this intervention ranges from US$25 to US$73 per DALY averted depending on the region. The intervention is cost saving in all regions.
"Legislation that mandates reducing the salt content of manufactured foods, accompanied by an educational campaign, can reduce blood pressure and would cost US$6 per person per year."
Legislation that mandates reducing the salt content of manufactured foods, accompanied by an educational campaign, can reduce blood pressure and would cost US$6 per person per year. This intervention would cost US$1,325 per DALY averted in South Asia and US$3,056 per DALY averted in the Middle East and North Africa.
Medical Interventions
When lifestyle changes are insufficient to avert CVD or diabetes, a variety of medical interventions exist. Many of these are sophisticated and expensive, such as grafting new arteries around the heart or opening a blockage with angioplasty, but relatively inexpensive treatments for chronic CVD are also available. For individuals who have suffered heart attacks, medications such as beta-blockers and aspirin can reduce the chance of a recurrence. The essential treatment for averting death from type 1 diabetes is insulin injections to maintain proper blood glucose levels. For type 2 diabetes, treatment requires changes in diet and physical activity, which are also needed for type 1 disease, and oral glucose-lowering agents, with insulin required only in severe cases. Blood pressure and lipids can also be controlled with pharmaceuticals. Other effective interventions for diabetes include early detection and screening followed by treatment for retinopathy, microalbuminuria, and foot disease.
"Even in middle-income countries . . . diabetics requiring glycemic control had access to insulin only 26 to 49 percent of the time."
Glucose levels of those with both type 1 and type 2 diabetes are currently poorly controlled in low- and middle-income countries. A 1997 survey by the International Diabetes Federation showed that no country in Africa had universal access to insulin for those who needed it. In the Democratic Republic of Congo, those with type 1 diabetes had access to insulin less than 25 percent of the time, implying a high mortality rate. Even in middle-income countries, such as El Salvador and Peru, diabetics requiring glycemic control had access to insulin only 26 to 49 percent of the time.
Most of the evidence regarding the cost-effectiveness of medical treatments for CVD and diabetes is from high-income countries. Medical interventions for CVD that are likely to be cost-effective in low- and middle-income countries include the following:
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anticlotting agents such as aspirin and heparin to prevent venous thromboembolism
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benzathine penicillin injections as secondary prevention, usually for five years, for those whose who have had rheumatic fever
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angiotensin-converting enzyme inhibitors for congestive heart failure
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anticoagulants for mitral stenosis and atrial fibrillation
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various drugs, including beta-blockers and off-patent statins, for long-term care of postmyocardial infarction.
Having defibrillators in emergency vehicles is highly cost-effective in high-income countries but is unlikely to be cost-effective in most lower-income countries. Nevertheless, having them available in hospitals may be cost-effective.
Medical researchers are pinning great hopes on the development of a so-called polypill to prevent CVD. The hypothetical polypill would combine several medications, including generic aspirin, a beta-blocker, a thiazide diuretic, an angiotensin-converting enzyme inhibitor, and a statin. When taken by a population with a 35 percent risk of CVD, the incremental cost-effectiveness ratio of such a polypill ranges from US$721 per DALY averted in the Middle East and North Africa to US$1,065 per DALY averted in East Asia and the Pacific. The cost-effectiveness is understandably lower in populations where the prevalence of CVD is lower.
"Medical researchers are pinning great hopes on the development of a so-called polypill to prevent CVD . . ."
The cost-effectiveness of medical interventions for diabetes varies greatly. Some are cost saving; others can cost more than US$73,000 per quality-adjusted life year gained. DCP2 estimates of the cost-effectiveness of these interventions explicitly incorporate differences in implementation, including the ease of reaching the targeted population and interventions' technical complexity, capital intensity, and cultural acceptability. Using this framework, glycemic control, blood pressure control, and foot care are all cost-effective and feasible.
" . . . for diabetes . . . glycemic control, blood pressure control, and foot care are all cost-effective and feasible."
Glycemic control costs less than managing the complications that arise in its absence. Ensuring adequate access to insulin is an important, cost-effective approach for people with type 1 diabetes, for whom insulin is essential. Blood pressure control for those with hypertension is also cost-effective and cost saving. Because many of the medications that control blood pressure are generic drugs, the drug cost in low- and middle-income countries is quite low. Furthermore, many people with diabetes in these countries also have poor control of their blood pressure. The combination makes these medications highly cost-effective.
Thus the cost-effectiveness of medical interventions varies considerably across contexts, depending on the availability of skilled personnel, the prices of drug, and the prevalence of risks. By contrast, lifestyle interventions are often cost saving because they avert conditions that can be costly to treat.
"By 2020, unless cancer prevention and screening interventions effectively reduce . . . incidence . . . the number of new cancer cases will increase from . . . 10 million cases in 2000 to an estimated 15 million . . ."
