EXPERTS PONDER THE GLOBAL RISE OF CHRONIC DISEASE
A growing global epidemic of chronic disease, such as heart disease, stroke, cancer and diabetes, will cause at least 35 million deaths this year, costing the world economy billions of dollars, even though medical science has identified the principal causes and knows ways to prevent it, experts said at a AAAS seminar in Washington, D.C.
Speakers at the first Philip Hauge Abelson Advancing Science Seminar said that twice as many premature deaths are caused worldwide by chronic diseases as by all infectious diseases, maternal and perinatal conditions and nutritional deficiencies combined. And while the toll from infectious diseases is declining globally, deaths from chronic disease are expected to increase by 17 percent in the next 10 years.
The 8 December seminar included speakers from the World Health Organization (WHO), from pharmaceutical and medical device manufacturers and from university research labs. It was the inaugural event in a series named for Abelson, a researcher in physics, biology and other sciences, and the editor for 22 years of Science, which is published by AAAS. Abelson died last year at the age of 91.
Alan I. Leshner, AAAS chief executive officer and executive publisher of Science, said the seminar series would address major societal challenges and focus on the frontiers of science and technology.
Robert Beaglehole, WHO’s director of Chronic Diseases and Health Promotion, said in the keynote address that the toll of premature death from chronic disease is increasing worldwide principally because of unhealthy diets, physical inactivity and the use of tobacco and the aging of populations in almost all countries.
Diet and the lack of physical activity is contributing to a growing pattern of obesity, a key risk factor for diabetes and early heart disease. And it’s not just happening in the rich countries, such as the United States and South Africa, where recent reports show that 75 percent of women aged 30 and over are overweight. A "very frightening statistic," said Beaglehole, is that in countries both rich and poor, about 22 million children worldwide under the age of five are already obese.
"We’ve done a lot to observe the emergence of this problem," he said. "We have done practically nothing to solve it."
Beaglehole said that common misunderstandings about chronic disease have affected policy decisions and slowed the worldwide response to the emerging epidemic.
For instance, he said it’s widely believed that premature heart disease, stroke, diabetes and other chronic diseases are mostly a plague among the elderly and among the rich in high-income countries.
Actually, said Beaglehole, 80 percent of deaths from chronic diseases are in low- and middle-income countries. A WHO report found that poor people, in all but the least developed countries, are more likely than the rich to develop chronic diseases and are more likely to die early. And it is not just the elderly who are victims. The WHO report found that almost half of the deaths from chronic diseases occur in people under 70 years old.
"A very dangerous misunderstanding is that chronic disease is the result of unhealthy lifestyles under the control of individuals," Beaglehole said. "The reality is that poor people and children have very limited choices, and it is unfair to blame them for the environmental conditions in which they suffer."
There’s also the belief by many that chronic diseases and premature deaths cannot be prevented.
"The reality is that approximately 80 percent of premature heart disease, stroke and type 2 diabetes is preventable, as are 40 percent of all cancers — many of which result from tobacco consumption," said Beaglehole. "A few known risk factors explain the vast majority of premature chronic disease deaths."
A global effort to attack the causes of chronic disease could reduce death rates by 2 percent a year and save 36 million lives within a decade, he said. Ninety percent of the lives saved, said Beaglehole, would be in low- and middle-income countries. Slowing the epidemic of premature death from chronic diseases will have to involve policy issues beyond the health field, he said. For instance, farm subsidies often affect the type of food available in some countries. An example: The consumption of full fat milk is encouraged in schools in some European countries because of subsidies, said Beaglehole. Excessive fat, sugar and salt in the diet lead to obesity, type 2 diabetes, heart disease and stroke.
Other specialists at the Abelson seminar reported recent findings that offer new hope for treatment and management of heart disease, high blood pressure, obesity, diabetes and cancer.
Eric J. Topol, provost of the Cleveland Clinic Lerner College of Medicine, said studies of families with heart attack have demonstrated specific genes that are causative or induce susceptibility. This will allow strategies of lifestyle and individualized therapy early in life to prevent heart attacks decades later.
The battle against the growing epidemic of obesity will require fundamental changes in attitudes toward food and exercise, said Holly Wyatt, the program director at the Centers for Obesity Research and Education at the University of Colorado Health Sciences Center. In American society, she said, "we’ve had a lot of pressures to not expend more energy than we have to and we had a lot of pressure to eat more than we need."
To change the behaviors that lead to obesity will require encouragement from virtually every element in society — employers, schools, churches, community centers and retail stores, she said. Such programs have worked in the past to discourage tobacco use and encourage using seat belts in cars. Without such an effort, Wyatt said that by 2008 about 75 percent of Americans will be at a body weight that negatively affects health.
Basic research on how the kidneys regulate salt in the body has given medical science a new understanding of the causes of high blood pressure, a major risk factor for heart attack, stroke and kidney failure, said Rick Lifton, Sterling Professor and chairman of Genetics atYale University School of Medicine. He said there are biological pathways and gene mutations that cause the kidneys to sequester sodium, leading to increases in blood pressure. Drugs to counter these effects could lead to dramatically improved treatments for hypertension, a disorder that affects a billion people world wide and is linked to about 5 million deaths annually.
Dr. Gerald I. Shulman, an investigator of the Howard Hughes Medical Institute and professor of internal medicine and cellular & molecular physiology at Yale University, said that new, non-invasive studies using magnetic resonance spectroscopy have demonstrated that the development of insulin resistance in type 2 diabetes is directly related to the build-up of fat inside muscle and liver cells where it disrupts normal insulin signaling and action in these organs. Studies in transgenic and knockout mice as well as in humans have shown that removing this excess intracellular fat can restore insulin sensitivity and cure type 2 diabetes. The results from these studies provide new targets for novel therapies that might be developed to reduce intracellular fat levels and reverse insulin resistance in patients with type 2 diabetes, said Shulman.
Copyright 2005. American Association for the Advancement of Science
