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July 25, 2002
Good morning. I am Dr. William Dietz, Director of the Division of Nutrition and Physical Activity at Centers for Disease Control and Prevention (CDC). I am pleased to be here today to participate in this important discussion on the risk of obesity and the scientific basis of diet and physical activity.
Burden of Obesity
The burden placed on our society by obesity and related chronic diseases is enormous. In the last 20 years, obesity rates have increased by more than 60 percent in adults. Since 1980, rates have doubled in children and tripled in adolescents. More than 25 percent of the adult population in the United States is obese, or approximately 50 million adults. Almost 15 percent of our children and adolescents are overweight, or approximately eight million youth. Rates of obesity and severe obesity are greater among African Americans and Mexican American women. Obesity in the United States is truly epidemic.
We have already begun to see the impact of the obesity epidemic on other diseases. For example, type 2 diabetes, a major consequence of obesity, also has increased rapidly over the last 10 years. Although type 2 diabetes in children and adolescents was virtually unknown 10 years ago, it now accounts for almost 50 percent of new cases of diabetes in some communities. Obesity is also a major contributor to heart disease, arthritis, and some types of cancer. Recent estimates suggest that obesity accounts for 300,000 deaths in the country annually, second only to tobacco related deaths.
The contribution of childhood onset obesity to adult disease is even more worrisome. Although onset of obesity in childhood only accounts for 25 percent of adult obesity, obese adults who were overweight children have much more severe obesity than adults who became obese in adulthood. Sixty percent of overweight children have at least one additional cardiovascular disease risk factor, and 25 percent have two or more. Hospitalization rates for the complications of obesity in children and adolescents have tripled.
The combination of chronic disease death and disability accounts for roughly 75 percent of the $1.3 trillion spent on health care each year in the United States. Last year, The Surgeon General's Call to Action to Prevent and Decrease Overweight and Obesity suggested that obesity and its complications were already costing the nation $117 billion annually. By way of comparison, obesity has roughly the same association with chronic health conditions as does 20 years of aging, and the costs of obesity were recently estimated to exceed the health care costs of smoking and problem drinking.
The recent increases in the prevalence of obesity indicate that obesity-associated diseases and the costs associated with them will also increase. For example, the prevalence of diabetes increased 49 percent between 1990 and 2000 (95 percent of all diagnosed diabetes cases are type 2). Type 2 diabetes was previously a disease of older adults, but now accounts for a substantial proportion of new cases of diabetes in children and adolescents. State Medicaid costs already account for 20 percent of an average state's budget. The epidemic of obesity and its associated diseases will likely increase these costs further. According to an American Diabetes Association cost study, the estimated economic cost of diabetes in 1997 was $98 billion. Of this amount, $44 billion was due to direct medical costs and $54 billion to lost productivity.
The rapid increases in obesity across the population and the burden of costly diseases that accompany obesity indicate we cannot afford to ignore this epidemic. The rapidity with which obesity has increased can only be explained by changes in the environment that have modified calorie intake and energy expenditure. Fast food consumption now accounts for more than 40 percent of a family's budget spent on food. Soft drink consumption supplies the average teenager with over 10 percent of their daily caloric intake. The variety of foods available has multiplied, and portion size has increased dramatically. Fewer children walk to school, and the lack of central shopping areas in our communities means that we make fewer trips on foot than we did 20 years ago. Hectic work and family schedules allow little time for physical activity. Schools struggling to improve academic achievement are dropping physical education and assigning more homework, which leaves less time for sports and physical activity. Television viewing has increased. Neighborhoods can be unsafe for walking, and parks may be unsafe for playing. Many office buildings tend to have inaccessible and uninviting stairwells that are seldom used, and many communities are built without sidewalks or bike trails to support physical activity.
Public Health Approach
The population that we are trying to reach is too large for us to rely solely upon individual interventions, which target one person at a time. Instead, the prevention of obesity will require coordinated policy and environmental changes that affect large populations simultaneously. The Secretary has identified obesity prevention as a priority within the Department of Health and Human Services. Many related activities are currently taking place within the Department and necessitate collaboration among agencies as well as the creation of public-private partnerships. The CDC has tried to develop effective prevention and treatment strategies through our state obesity programs, state coordinated school health programs, partnerships with other organizations, and an applied research agenda.
A Coordinated Strategy to Address the Obesity Epidemic
Currently CDC funds 12 states to prevent and reduce obesity and its chronic related diseases. Our support permits states to develop and test nutrition and physical activity interventions to prevent obesity through strategies that focus on policy-level changes (e.g., States assess and rate childcare centers for nutrition and active play) or a supportive environment (e.g., competitive pricing of fruits and vegetables in school cafeterias). For example, in Massachusetts, The National Institutes of Health (NIH) funded a school-based obesity curriculum known as Planet Health. This curriculum, which integrated reduced fat, increased fruit and vegetable intake, increased physical activity, and reduced television; with messages in science, math, language and social studies classes significantly reduced obesity in adolescent girls. The CDC is now supporting the expansion of this program into public, charter, and parochial school systems in Boston.
Another example is the North Carolina Healthy Weight Initiative, which involves communities and an energetic statewide task force comprised of community leaders and health professionals. The group has developed a curriculum known as "Color Me Healthy" for 4 and 5 year olds that focuses on interactive, innovative learning opportunities on eating healthy and being active. Through an innovative collaboration with the U.S. Department of Agriculture (USDA), implementation of "Color Me Healthy" is underway in 71 counties through cooperative extension and the Special Supplemental Nutrition Program for Women, Infants and Children (WIC). These programs help illustrate how CDC-funded programs translate research findings into practice, and integrate Department of Health and Human Services (DHHS) activities with those of other government agencies.
In addition to the collaboration with state health departments, CDC also funds 20 state educational agencies through the Coordinated School Health Program. This program reaches students in elementary and secondary schools and strives to increase physical activity and improve the nutrition among our nation's young people. Through this program, the CDC awards competitive grants to state, tribal, and territorial educational agencies to:
As part of this program, many states have begun to implement their own strategies. For example, West Virginia has adopted one of the strongest standards for school nutrition in the nation. The West Virginia Board of Education prohibits the sale or serving of the following foods at school: chewing gum, flavored ice bars, and candy bars; foods or drinks containing 40 percent or more, by weight, of sugar or other sweeteners; juice or juice products containing less than 20 percent real fruit or vegetable juice; and food(s) with more than eight grams of fat per one-ounce serving. At West Virginia elementary and middle schools, soft drinks are prohibited. In addition to implementing these policies, the West Virginia Department of Education Office of Healthy Schools collaborated with the Office of Child Nutrition and the West Virginia Nutrition Coalition plan and delivered a week-long nutrition symposium for school food service, health education, and school health services professionals. These programs impact more than 300,000 students in a state where over 25 percent of the children ages 5–17 live in poverty.
CDC's coordinated school health program enables state departments of education and health to work together efficiently, respond to changing health priorities, and effectively use limited resources to meet a wide range of health needs among the state's school-aged population.
National or state programs alone will not succeed unless they are supported by a wide array of partnerships. Nutrition and physical activity programs must be integrated across other CDC-funded state programs aimed at cancer, diabetes, and cardiovascular disease. In addition, as the North Carolina program emphasizes, nutrition and physical activity programs must be linked to other departments, such as the USDA. Groups that share concerns about the impact of obesity on other diseases, such as the American Heart Association and the American Cancer Society, are natural allies in obesity prevention efforts. For example, the CDC is exploring joint training activities with the American Cancer Society around nutrition and physical activity strategies within states.
At least four behavior change strategies appear justified by the current state of our knowledge. These include the development of sophisticated marketing messages designed to increase health behaviors among youth, reduced television viewing in children and adolescents, increased physical activity for the population, and the promotion of breast feeding and efforts to increase its duration.
The prevalence of obesity has been directly related to the amount of time children and adolescents watch television, and therefore reducing television time appears to be an effective strategy to treat and prevent obesity. Nonetheless, incentives for parents to reduce the amount of time their children watch television must still be identified. Some research suggests that parental concerns about televised violence or sexuality may be more persuasive reasons than obesity prevention to control children's television time.
Physical activity represents our most effective strategy for obesity and the one for which the most substantial body of evidence exists. Increased physical activity for overweight patients reduces many of the co-morbidities associated with obesity such as hypertension, hyperlipidemia, and glucose intolerance. The chapter on Physical Activity in the Guide for Community Preventive Services lists six evidence-based strategies that can be used to increase physical activity. These include large-scale, intense, highly visible, community-wide campaigns; point-of-decision prompts that encourage people to use the stairs instead of the elevators; physical education programs in schools; providing social support for increasing physical activity; individually adapted health behavior change programs; and enhanced access to places for physical activity.
Large-scale, intense, highly visible, community-wide campaigns are effective in both rural and urban communities and among different ethnic and socioeconomic groups. Such campaigns direct their messages to large audiences through different types of media, including television, radio, newspapers, movie theaters, billboards, and mailings. They promote activities such as support or self-help groups, physical activity counseling, risk factor screening and education, health fairs, and environmental changes such as the creation of walking trails.
Point-of-decision prompts that encourage people to use the stairs instead of elevators or escalators are effective in getting people to be more physically active. Point-of-decision prompts are signs that encourage people to use nearby stairs for health benefits or weight loss. These signs tell people about the health benefits from taking the stairs, and they remind people who already want to be more active that an opportunity to be physically active is at hand. These type of interventions are effective in a variety of settings including train, subway and bus stations, shopping malls and university libraries. They are also effective among different population subgroups - both men and women, both obese and not obese individuals.
Physical education programs in schools provide a safe supervised opportunity for physical activity for children and adolescents. Daily participation in physical education among high schools students has declined from 42 percent in 1991 to 29 percent in 1999. Physical activity may improve class room behavior and performance.
Efforts made in community settings to provide social support for increasing physical activity are effective. These interventions focus on changing physical activity behavior through building, strengthening, and maintaining social networks that provide supportive relationships for behavior change (e.g., setting up a buddy system, making contracts with others to complete specified levels of physical activity, and setting up walking groups to provide friendship and support). Interventions involve either creating new social networks or working within existing networks, such as in the workplace. These interventions are effective in various settings including communities, worksites, and universities, men and women, among adults of different ages, and among both sedentary people and those who are already active.
Also effective are individually adapted health behavior change programs, which teach behavioral skills to help participants incorporate physical activity into their daily routines. Programs should be tailored to each individual's specific interests, preferences, and readiness for change. These programs teach behavioral skills such as: goal-setting and self-monitoring of progress toward those goals; building social support for new behaviors; behavioral reinforcement through self-reward and positive self-talk; structured problem solving to maintain the behavior change; and, prevention of relapse into sedentary behavior. These interventions may be delivered to people either in-group settings or by mail, telephone, directed media or by health care providers and are effective among both men and women.
Access to places for physical activity provides opportunities for those who are motivated to utilize such facilities. Promotion of trails or park use enhances the likelihood that recreational facilities will be utilized. The Department of Health and Human Services, the National Park Service, U.S. Department of Agriculture, and the Army Corps of Engineers recently signed a Memorandum of Understanding to promote outdoor lands for physical activity.
Breast feeding is unquestionably the most appropriate form of feeding for most infants, and clearly reduces the incidence of acute diseases of infancy and early childhood. Recent studies of breast-feeding indicate that children who are breast-fed appear to have a reduced risk of obesity later in life. Nonetheless, only 64 percent of new mothers initiate breast feeding, and only about 29 percent have continued breast feeding six months after birth. A major research objective is to understand how to increase breast feeding rates and duration through strategies such as spouse support or worksite modifications that permit mothers to continue to feed their children breast milk after they return to work.
Medical approaches are an integral part of weight control. When 25 percent of adults are affected with obesity, the effective translation of proven strategies into approaches that can be used in primary care settings must become a high priority. We recently calculated what it would cost if all obese Americans were started on one of the two available drugs for the treatment of obesity. The costs of drug therapy were approximately the same as the direct costs of obesity. This observation indicates that conventional medical therapy for the treatment of obesity is extremely expensive. However, last year an NIH clinical trial demonstrated that diet, exercise, and modest weight loss decreased the incidence of diabetes by almost 60 percent - a far greater improvement than the pharmaceutical therapy in the comparison group. These results emphasize the importance of lifestyle modification in the treatment of prediabetes. We are currently working with several managed care organizations to begin the process of translating these approaches into strategies that can be used in primary care. In a meeting to be held this summer, we will begin the process of identifying simple and effective counseling techniques that can be used by physicians, nurse practitioners and nutritionists to help obese patients. Evaluation of these approaches will be critical.
Dietary Supplement Use
Investigators at CDC recently examined the usage of nonprescription weight loss products by adults in five states, including Florida, Iowa, Michigan, West Virginia, and Wisconsin. Seven percent of adults reported that they had used an over-the-counter (OTC) weight loss product in the past two years. Two percent reported the use of phenylpropanolamine, and one percent reported the use of an ephedra product. As expected, use of OTC products was increased among obese women. Almost 30 percent of obese women and 14 percent of obese men reported use of an OTC drug in the past two years. An important limitation of these surveys was the relatively limited number of questions that could be asked and the small sample size. Therefore, we have been pleased to help the Office of Dietary Supplements at NIH collect data from a greater number of adults in South Carolina. These data will help clarify the frequency and duration associated with the use of these products, as well as whether information about OTC drug use was discussed with their physicians.
In summary, obesity in the United States is epidemic and it is adversely affecting the health and well-being of Americans. The diseases associated with obesity like diabetes have also begun to increase, and are already adding to health care costs. CDC programs have begun to address the problem of obesity, but are small and just beginning. Nonetheless, comprehensive nutrition and physical activity approaches to prevent and treat obesity appear the most cost-effective strategy to reduce obesity and its complications.
Thank you for the opportunity to talk about this very critical issue. I would be happy to answer any questions the Committee may have.
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Last revised: July 25, 2002