Answers on Childhood Obesity
Dr. William H. Dietz, Director of the Division of Nutrition, Physical Activity and Obesity Prevention in the Center for Chronic Disease Prevention and Health Promotion at the Centers for Disease Control and Prevention (CDC), is one of the nation’s most renowned experts on childhood obesity.
Q. A plateau in childhood obesity levels was recently reported in JAMA. Are you concerned that people will lose concern for this issue?
A. For the longest time, obesity was thought of as a cosmetic problem not a health problem. In my view, the focus on the adverse health effects of childhood obesity and the many initiatives begun in schools and communities since 2000 may be accounting for the apparent plateau reported in children between 2003 and 2006. However, if you listen carefully to what people are saying, including me, that only means we are at the corner; it doesn’t mean we have turned the corner on the epidemic. With a prevalence of childhood obesity at roughly 18 percent and 30 percent in adults, we can’t assume we’ve solved the problem. It is going to take significant cultural, policy and environmental changes. I think the plateau reflects an awareness of the health effects of childhood obesity, but we can’t be complacent because we have not yet turned it around.
Q. How long has childhood obesity been considered an epidemic?
A. In the early 1980s, we proposed that the prevalence of pediatric obesity was increasing based on skin folds; BMI (body mass index) was not a widely accepted measurement at the time. A seminal study was the association of television viewing and obesity in children in 1985. However, awareness, or a more general sensitivity to this issue, really began in the early part of this decade with the publication of the trend maps based on state obesity data. (Viewable at www.cdc.gov).
Q. Is childhood obesity more prevalent in the United States or is it a global issue?
A. Every country that has longitudinal data is showing an increase. There is an even higher prevalence in some countries in the Middle East and in Micronesia than in the United States, but as yet we do not have enough data to know why. Nor do we have sufficient current data to analyze urban and rural population comparisons.
Q. How is childhood obesity measured?
A. BMI is used as the standard measure of obesity in children. However, it is based on percentiles because children are growing. The definition of obesity in children is a BMI greater than the 95th percentile for children who are the same age and sex.
Q. What are the consequences of childhood obesity?
A. Childhood obesity is associated with a variety of cardiovascular disease risk factors such as elevated blood pressure, elevated lipid levels, and elevated insulin or glucose, which are precursors for heart disease or Type 2 diabetes in young adults. We know roughly 15 years elapses between the diagnosis of Type 2 diabetes and the appearance of complications like renal disease. For a fifteen year old diagnosed today, that would mean that by age 30 there would be a substantial likelihood of having the burden of chronic disease associated with the diagnosis. We know that obesity has accounted for over 25 percent of the increase in medical cost between 1987 and 2000. Some estimates place its annual cost at over 100 billion dollars a year. The crisis in health care costs suggest we need to focus on the prevention of childhood obesity.
Q. What factors contribute to childhood obesity?
A. There is no single factor. There have been such major changes in the food supply and our access to it, how we consume it, as well as major changes in our physical activity levels and patterns. Both increased energy intake and reduced energy expenditure have contributed to this epidemic. Also, the social norms about fatness have shifted. Because the BMI of the pediatric population has increased, increased body fat is not recognized as abnormal. There is a higher prevalence of childhood obesity if one parent is obese and an even greater prevalence if both parents are obese. Some data also suggests that severe obesity in children and adolescents is associated with a higher risk of family dysfunction around issues such as drug use, divorce, alcohol use, or physical abuse.
Q. Is there a genetic component to childhood obesity?
A. Yes, but that gene doesn’t get expressed unless there is an environment that fosters increased food intake or reduced physical activity. There is clearly a genetic-environment interaction. Those genes were present in the population 30 years ago before obesity started to increase. It is the change in environmental factors that have promoted the development of obesity.
Q. Is there an effective strategy to combat childhood obesity?
A. The behaviors that we have targeted are promoting increased physical activity, breast-feeding, and fruit and vegetable consumption and reducing the intake of high-energy density foods, sugar sweetened beverages and television time. We have to address several of these variables simultaneously if we are going to make any progress.
Q. What are some of the challenges to implementing that strategy?
A. Between 2000 and 2006, there have been many significant changes, for example: the types of foods available and physical activity programs in schools, and community programs that have been associated with a successful reduction in obesity.
However, some initiatives may not have a very strong evaluation component. One of the things that we lack the most right now are intervention studies which demonstrate what we can do to effectively reverse obesity in a variety of settings like schools or communities.
Q. How important is the work of organizations such as the Michael & Susan Del Center for Advancement of Healthy Living to that strategy?
A. The federal government doesn’t have a lot of money to do this, so support from groups including the Michael & Susan Dell Foundation is critically important. Funders have in many respects helped to drive the agenda on obesity. The foundation’s investment in CATCH in Texas is a terribly important initiative and could make a significant contribution to the control of this problem.
Q. What can be done right now to make a difference?
A. In my view, it is going to take a multi-component approach in multiple settings to turn the childhood obesity trend around. Simple school based intervention by itself or medical counseling about the need for parents to provide children with fruits and vegetables is not going to work unless complemented by community based changes. Our children can’t very well be active if they live in a neighborhood that isn’t safe or doesn’t have sidewalks or access to recreational facilities. Parents can’t very well increase fruit and vegetable consumption if there’s no access to supermarkets. We have to make efforts to change the environments in which children live to foster better nutrition and physical activity.
Q. What is your outlook on this issue?
A. We haven’t yet gotten to the point where we have instituted the types of policies or environmental changes that I think are going to lead to a decrease in obesity. I’m not quite sure what’s its going to take to turn the corner. However, I think we are making a difference and I am optimistic.
Dr. William H. Dietz, Director of the Division of Nutrition, Physical Activity and Obesity Prevention in the Center for Chronic Disease Prevention and Health Promotion at the Centers for Disease Control and Prevention (CDC), is one of the nation’s most renowned experts on childhood obesity.
Q. A plateau in childhood obesity levels was recently reported in JAMA. Are you concerned that people will lose concern for this issue?
A. For the longest time, obesity was thought of as a cosmetic problem not a health problem. In my view, the focus on the adverse health effects of childhood obesity and the many initiatives begun in schools and communities since 2000 may be accounting for the apparent plateau reported in children between 2003 and 2006. However, if you listen carefully to what people are saying, including me, that only means we are at the corner; it doesn’t mean we have turned the corner on the epidemic. With a prevalence of childhood obesity at roughly 18 percent and 30 percent in adults, we can’t assume we’ve solved the problem. It is going to take significant cultural, policy and environmental changes. I think the plateau reflects an awareness of the health effects of childhood obesity, but we can’t be complacent because we have not yet turned it around.
Q. How long has childhood obesity been considered an epidemic?
A. In the early 1980s, we proposed that the prevalence of pediatric obesity was increasing based on skin folds; BMI (body mass index) was not a widely accepted measurement at the time. A seminal study was the association of television viewing and obesity in children in 1985. However, awareness, or a more general sensitivity to this issue, really began in the early part of this decade with the publication of the trend maps based on state obesity data. (Viewable at www.cdc.gov).
Q. Is childhood obesity more prevalent in the United States or is it a global issue?
A. Every country that has longitudinal data is showing an increase. There is an even higher prevalence in some countries in the Middle East and in Micronesia than in the United States, but as yet we do not have enough data to know why. Nor do we have sufficient current data to analyze urban and rural population comparisons.
Q. How is childhood obesity measured?
A. BMI is used as the standard measure of obesity in children. However, it is based on percentiles because children are growing. The definition of obesity in children is a BMI greater than the 95th percentile for children who are the same age and sex.
Q. What are the consequences of childhood obesity?
A. Childhood obesity is associated with a variety of cardiovascular disease risk factors such as elevated blood pressure, elevated lipid levels, and elevated insulin or glucose, which are precursors for heart disease or Type 2 diabetes in young adults. We know roughly 15 years elapses between the diagnosis of Type 2 diabetes and the appearance of complications like renal disease. For a fifteen year old diagnosed today, that would mean that by age 30 there would be a substantial likelihood of having the burden of chronic disease associated with the diagnosis. We know that obesity has accounted for over 25 percent of the increase in medical cost between 1987 and 2000. Some estimates place its annual cost at over 100 billion dollars a year. The crisis in health care costs suggest we need to focus on the prevention of childhood obesity.
Q. What factors contribute to childhood obesity?
A. There is no single factor. There have been such major changes in the food supply and our access to it, how we consume it, as well as major changes in our physical activity levels and patterns. Both increased energy intake and reduced energy expenditure have contributed to this epidemic. Also, the social norms about fatness have shifted. Because the BMI of the pediatric population has increased, increased body fat is not recognized as abnormal. There is a higher prevalence of childhood obesity if one parent is obese and an even greater prevalence if both parents are obese. Some data also suggests that severe obesity in children and adolescents is associated with a higher risk of family dysfunction around issues such as drug use, divorce, alcohol use, or physical abuse.
Q. Is there a genetic component to childhood obesity?
A. Yes, but that gene doesn’t get expressed unless there is an environment that fosters increased food intake or reduced physical activity. There is clearly a genetic-environment interaction. Those genes were present in the population 30 years ago before obesity started to increase. It is the change in environmental factors that have promoted the development of obesity.
Q. Is there an effective strategy to combat childhood obesity?
A. The behaviors that we have targeted are promoting increased physical activity, breast-feeding, and fruit and vegetable consumption and reducing the intake of high-energy density foods, sugar sweetened beverages and television time. We have to address several of these variables simultaneously if we are going to make any progress.
Q. What are some of the challenges to implementing that strategy?
A. Between 2000 and 2006, there have been many significant changes, for example: the types of foods available and physical activity programs in schools, and community programs that have been associated with a successful reduction in obesity.
However, some initiatives may not have a very strong evaluation component. One of the things that we lack the most right now are intervention studies which demonstrate what we can do to effectively reverse obesity in a variety of settings like schools or communities.
Q. How important is the work of organizations such as the Michael & Susan Del Center for Advancement of Healthy Living to that strategy?
A. The federal government doesn’t have a lot of money to do this, so support from groups including the Michael & Susan Dell Foundation is critically important. Funders have in many respects helped to drive the agenda on obesity. The foundation’s investment in CATCH in Texas is a terribly important initiative and could make a significant contribution to the control of this problem.
Q. What can be done right now to make a difference?
A. In my view, it is going to take a multi-component approach in multiple settings to turn the childhood obesity trend around. Simple school based intervention by itself or medical counseling about the need for parents to provide children with fruits and vegetables is not going to work unless complemented by community based changes. Our children can’t very well be active if they live in a neighborhood that isn’t safe or doesn’t have sidewalks or access to recreational facilities. Parents can’t very well increase fruit and vegetable consumption if there’s no access to supermarkets. We have to make efforts to change the environments in which children live to foster better nutrition and physical activity.
Q. What is your outlook on this issue?
A. We haven’t yet gotten to the point where we have instituted the types of policies or environmental changes that I think are going to lead to a decrease in obesity. I’m not quite sure what’s its going to take to turn the corner. However, I think we are making a difference and I am optimistic.