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Quote:
'Overweight' appears to be optimal in mortality study
By Gina Kolata The New York Times Wednesday, April 20, 2005
People who are overweight have a lower death risk than those of normal weight, federal researchers in the United States will report Wednesday in the newest and most comprehensive study of the impact of obesity.
The researchers, statisticians and epidemiologists from the Centers for Disease Control and the National Cancer Institute, also found that the risks of obesity were not apparent until people became extremely obese, a group that constitutes only 8 percent of Americans. But being very thin - even though the thinness was not caused by disease - also caused a slight increase in the death risk the researchers report.
The new study, which others said is the most rigorous yet, took into account such factors as smoking, age, race and alcohol consumption in a sophisticated statistical analysis derived from a well-known method that has been used to predict cancer risk.
It also used the federal government's own definitions of weight categories that measure fatness according to body mass index, an estimate of weight for height.
For example, people 173 centimeters tall, or 5 feet 8 inches, and weighing less than 55 kilograms, or 122 pounds, are underweight. If they weighed from 55 kilograms to 74 kilograms, their weight would be normal. They would be overweight if their weight was 74 to 88 kilograms. And if they weighed more than 88 kilograms, they would be obese.
In the new study, nearly all the death risk from obesity occurred in the heaviest of the obese, like 173-centimeter person weighing more than 104 kilograms.
But the findings are unexpected and researchers are reacting with a full gamut of responses. Some see the report as a long-needed reality check on what they see as the nation's near-hysteria over fat.
"I love it," said Dr. Steven Blair, who is president and chief executive of the Cooper Institute, a nonprofit research and educational organization in Dallas that focuses on preventive medicine.
Blair, whose data indicate that fitness is more important than fatness, added: "There are people who have made up their minds that obesity and overweight are the biggest public health problem that we have to face. These numbers show that maybe it's not that big."
Others said they simply did not believe the findings. Dr. Joann Manson, chief of preventive medicine at Harvard's Brigham and Women's Hospital, pointed to Harvard's own study of nurses that found mortality risks in being overweight and even greater risks in being obese. "We can't afford to be complacent about the epidemic of obesity," she said.
Dr. Mark Mattson a rail-thin researcher at the National Institute on Aging, who studies caloric restriction as a means to prolong life, said that while the results on very thin people are unexpected, it also is not clear that eating fewer calories means weighing so little. Caloric restriction might extend life, he said, but, he added, "there's certainly a point where you can overdo it with caloric restriction, and we don't know what that point is."
Other statisticians and epidemiologists commented that their methods and data were exemplary and their analysis compelling. They also said that the study's authors, Dr. Katherine Flegal, Dr. David Williamson, Dr. Barry Graubard and Dr. Mitchell Gail, were highly regarded and experienced scientists.
"This is a well known group, and I thought their analysis and their statistical approaches were very good," said Dr. Barbara Hulka, an emeritus professor of epidemiology at the University of North Carolina.
"This is clearly the best analysis - the best thought out and with the best data - that anyone has presented," said Dr. Daniel McGee Jr., a professor of statistics at Florida State University.
The study did not explain why overweight appears best as far as mortality is concerned. But one of the authors, Williamson, of the Centers for Disease Control and Prevention, said it may be because most people die when they are over 70, and having a bit of extra fat appears to be protective. "It's called the obesity paradox," Williamson said. But, he said, while the paradox is real, the reasons are speculative. "It's raw conjecture."
But, the investigators said, it also is possible that obesity and overweight are less of a health risk than they used to be.
In a paper published in the same issue of the Journal of the American Medical Association, Williamson and his colleagues report that high blood pressure and high cholesterol levels are less prevalent now then they were 30 or 40 years ago, and fatter people made the greatest improvements in controlling these conditions that can lead to heart disease. People are also smoking less. Diabetes remains the same, however, afflicting about 4 percent of people of normal weight, 6 percent of those who are overweight, and 14 percent of the obese.
The new study comes just 13 months after different researchers from the Centers from Disease Control and Prevention published a paper in the same journal and signed by the center's director, Dr. Julie Gerberding, warning that obesity and overweight were causing an extra 400,000 deaths a year and that soon excess weight was going to overtake smoking as the nation's leading preventable cause of premature death.
Now, according to the current study, obesity is causing about 111,000 extra deaths, but overweight is preventing about 86,000 deaths that would have been expected if those overweight people were in the normal weight range. And underweight is causing about 34,000 deaths a year.
Dr. Donna Stroup, the director of the Center for Disease Control's coordinating center for health promotion, speaking for the agency, did not take issue with the new figures. "From a scientific point of view, they are a step forward," she said. But, she added, the new analysis looks only at how long people live, not at the quality of their lives.
"Mortality really only represents the tip of the iceberg of the magnitude of the problem," Stroup said.
Estimating deaths due to obesity or overweight is a statistical challenge, the study investigators said. The idea is to determine, for each person in the population, what would be their risk of dying if you could move their weight to a normal weight.
For people whose weight is already in that range there would be no change in the risk of dying, of course. The question is, What happens to the risk for people whose weights are above or below the healthy range? The statistical adjustment comes because the idea is to keep factors like age, smoking and gender the same and ask what would happen if only weight was changed.
The message, Williamson said, is that perhaps people ought to take other factors into consideration when deciding whether to worry about the health risks of their weight.
Dr. Barry Glassner, a sociology professor at the University of Southern California who has scrutinized the obesity data, had a different message.
"The take-home message from this study it seems to me is unambiguous," he said. "What is officially deemed overweight these days is actually the optimal weight."
See more of the world that matters - click here for home delivery of the International Herald Tribune.
People who are overweight have a lower death risk than those of normal weight, federal researchers in the United States will report Wednesday in the newest and most comprehensive study of the impact of obesity.
The researchers, statisticians and epidemiologists from the Centers for Disease Control and the National Cancer Institute, also found that the risks of obesity were not apparent until people became extremely obese, a group that constitutes only 8 percent of Americans. But being very thin - even though the thinness was not caused by disease - also caused a slight increase in the death risk the researchers report.
The new study, which others said is the most rigorous yet, took into account such factors as smoking, age, race and alcohol consumption in a sophisticated statistical analysis derived from a well-known method that has been used to predict cancer risk.
It also used the federal government's own definitions of weight categories that measure fatness according to body mass index, an estimate of weight for height.
For example, people 173 centimeters tall, or 5 feet 8 inches, and weighing less than 55 kilograms, or 122 pounds, are underweight. If they weighed from 55 kilograms to 74 kilograms, their weight would be normal. They would be overweight if their weight was 74 to 88 kilograms. And if they weighed more than 88 kilograms, they would be obese.
In the new study, nearly all the death risk from obesity occurred in the heaviest of the obese, like 173-centimeter person weighing more than 104 kilograms.
But the findings are unexpected and researchers are reacting with a full gamut of responses. Some see the report as a long-needed reality check on what they see as the nation's near-hysteria over fat.
"I love it," said Dr. Steven Blair, who is president and chief executive of the Cooper Institute, a nonprofit research and educational organization in Dallas that focuses on preventive medicine.
Blair, whose data indicate that fitness is more important than fatness, added: "There are people who have made up their minds that obesity and overweight are the biggest public health problem that we have to face. These numbers show that maybe it's not that big."
Others said they simply did not believe the findings. Dr. Joann Manson, chief of preventive medicine at Harvard's Brigham and Women's Hospital, pointed to Harvard's own study of nurses that found mortality risks in being overweight and even greater risks in being obese. "We can't afford to be complacent about the epidemic of obesity," she said.
Dr. Mark Mattson a rail-thin researcher at the National Institute on Aging, who studies caloric restriction as a means to prolong life, said that while the results on very thin people are unexpected, it also is not clear that eating fewer calories means weighing so little. Caloric restriction might extend life, he said, but, he added, "there's certainly a point where you can overdo it with caloric restriction, and we don't know what that point is."
Other statisticians and epidemiologists commented that their methods and data were exemplary and their analysis compelling. They also said that the study's authors, Dr. Katherine Flegal, Dr. David Williamson, Dr. Barry Graubard and Dr. Mitchell Gail, were highly regarded and experienced scientists.
"This is a well known group, and I thought their analysis and their statistical approaches were very good," said Dr. Barbara Hulka, an emeritus professor of epidemiology at the University of North Carolina.
"This is clearly the best analysis - the best thought out and with the best data - that anyone has presented," said Dr. Daniel McGee Jr., a professor of statistics at Florida State University.
The study did not explain why overweight appears best as far as mortality is concerned. But one of the authors, Williamson, of the Centers for Disease Control and Prevention, said it may be because most people die when they are over 70, and having a bit of extra fat appears to be protective. "It's called the obesity paradox," Williamson said. But, he said, while the paradox is real, the reasons are speculative. "It's raw conjecture."
But, the investigators said, it also is possible that obesity and overweight are less of a health risk than they used to be.
In a paper published in the same issue of the Journal of the American Medical Association, Williamson and his colleagues report that high blood pressure and high cholesterol levels are less prevalent now then they were 30 or 40 years ago, and fatter people made the greatest improvements in controlling these conditions that can lead to heart disease. People are also smoking less. Diabetes remains the same, however, afflicting about 4 percent of people of normal weight, 6 percent of those who are overweight, and 14 percent of the obese.
The new study comes just 13 months after different researchers from the Centers from Disease Control and Prevention published a paper in the same journal and signed by the center's director, Dr. Julie Gerberding, warning that obesity and overweight were causing an extra 400,000 deaths a year and that soon excess weight was going to overtake smoking as the nation's leading preventable cause of premature death.
Now, according to the current study, obesity is causing about 111,000 extra deaths, but overweight is preventing about 86,000 deaths that would have been expected if those overweight people were in the normal weight range. And underweight is causing about 34,000 deaths a year.
Dr. Donna Stroup, the director of the Center for Disease Control's coordinating center for health promotion, speaking for the agency, did not take issue with the new figures. "From a scientific point of view, they are a step forward," she said. But, she added, the new analysis looks only at how long people live, not at the quality of their lives.
"Mortality really only represents the tip of the iceberg of the magnitude of the problem," Stroup said.
Estimating deaths due to obesity or overweight is a statistical challenge, the study investigators said. The idea is to determine, for each person in the population, what would be their risk of dying if you could move their weight to a normal weight.
For people whose weight is already in that range there would be no change in the risk of dying, of course. The question is, What happens to the risk for people whose weights are above or below the healthy range? The statistical adjustment comes because the idea is to keep factors like age, smoking and gender the same and ask what would happen if only weight was changed.
The message, Williamson said, is that perhaps people ought to take other factors into consideration when deciding whether to worry about the health risks of their weight.
Dr. Barry Glassner, a sociology professor at the University of Southern California who has scrutinized the obesity data, had a different message.
"The take-home message from this study it seems to me is unambiguous," he said. "What is officially deemed overweight these days is actually the optimal weight."
See more of the world that matters - click here for home delivery of the International Herald Tribune.
People who are overweight have a lower death risk than those of normal weight, federal researchers in the United States will report Wednesday in the newest and most comprehensive study of the impact of obesity.
The researchers, statisticians and epidemiologists from the Centers for Disease Control and the National Cancer Institute, also found that the risks of obesity were not apparent until people became extremely obese, a group that constitutes only 8 percent of Americans. But being very thin - even though the thinness was not caused by disease - also caused a slight increase in the death risk the researchers report.
The new study, which others said is the most rigorous yet, took into account such factors as smoking, age, race and alcohol consumption in a sophisticated statistical analysis derived from a well-known method that has been used to predict cancer risk.
It also used the federal government's own definitions of weight categories that measure fatness according to body mass index, an estimate of weight for height.
For example, people 173 centimeters tall, or 5 feet 8 inches, and weighing less than 55 kilograms, or 122 pounds, are underweight. If they weighed from 55 kilograms to 74 kilograms, their weight would be normal. They would be overweight if their weight was 74 to 88 kilograms. And if they weighed more than 88 kilograms, they would be obese.
In the new study, nearly all the death risk from obesity occurred in the heaviest of the obese, like 173-centimeter person weighing more than 104 kilograms.
But the findings are unexpected and researchers are reacting with a full gamut of responses. Some see the report as a long-needed reality check on what they see as the nation's near-hysteria over fat.
"I love it," said Dr. Steven Blair, who is president and chief executive of the Cooper Institute, a nonprofit research and educational organization in Dallas that focuses on preventive medicine.
Blair, whose data indicate that fitness is more important than fatness, added: "There are people who have made up their minds that obesity and overweight are the biggest public health problem that we have to face. These numbers show that maybe it's not that big."
Others said they simply did not believe the findings. Dr. Joann Manson, chief of preventive medicine at Harvard's Brigham and Women's Hospital, pointed to Harvard's own study of nurses that found mortality risks in being overweight and even greater risks in being obese. "We can't afford to be complacent about the epidemic of obesity," she said.
Dr. Mark Mattson a rail-thin researcher at the National Institute on Aging, who studies caloric restriction as a means to prolong life, said that while the results on very thin people are unexpected, it also is not clear that eating fewer calories means weighing so little. Caloric restriction might extend life, he said, but, he added, "there's certainly a point where you can overdo it with caloric restriction, and we don't know what that point is."
Other statisticians and epidemiologists commented that their methods and data were exemplary and their analysis compelling. They also said that the study's authors, Dr. Katherine Flegal, Dr. David Williamson, Dr. Barry Graubard and Dr. Mitchell Gail, were highly regarded and experienced scientists.
"This is a well known group, and I thought their analysis and their statistical approaches were very good," said Dr. Barbara Hulka, an emeritus professor of epidemiology at the University of North Carolina.
"This is clearly the best analysis - the best thought out and with the best data - that anyone has presented," said Dr. Daniel McGee Jr., a professor of statistics at Florida State University.
The study did not explain why overweight appears best as far as mortality is concerned. But one of the authors, Williamson, of the Centers for Disease Control and Prevention, said it may be because most people die when they are over 70, and having a bit of extra fat appears to be protective. "It's called the obesity paradox," Williamson said. But, he said, while the paradox is real, the reasons are speculative. "It's raw conjecture."
But, the investigators said, it also is possible that obesity and overweight are less of a health risk than they used to be.
In a paper published in the same issue of the Journal of the American Medical Association, Williamson and his colleagues report that high blood pressure and high cholesterol levels are less prevalent now then they were 30 or 40 years ago, and fatter people made the greatest improvements in controlling these conditions that can lead to heart disease. People are also smoking less. Diabetes remains the same, however, afflicting about 4 percent of people of normal weight, 6 percent of those who are overweight, and 14 percent of the obese.
The new study comes just 13 months after different researchers from the Centers from Disease Control and Prevention published a paper in the same journal and signed by the center's director, Dr. Julie Gerberding, warning that obesity and overweight were causing an extra 400,000 deaths a year and that soon excess weight was going to overtake smoking as the nation's leading preventable cause of premature death.
Now, according to the current study, obesity is causing about 111,000 extra deaths, but overweight is preventing about 86,000 deaths that would have been expected if those overweight people were in the normal weight range. And underweight is causing about 34,000 deaths a year.
Dr. Donna Stroup, the director of the Center for Disease Control's coordinating center for health promotion, speaking for the agency, did not take issue with the new figures. "From a scientific point of view, they are a step forward," she said. But, she added, the new analysis looks only at how long people live, not at the quality of their lives.
"Mortality really only represents the tip of the iceberg of the magnitude of the problem," Stroup said.
Estimating deaths due to obesity or overweight is a statistical challenge, the study investigators said. The idea is to determine, for each person in the population, what would be their risk of dying if you could move their weight to a normal weight.
For people whose weight is already in that range there would be no change in the risk of dying, of course. The question is, What happens to the risk for people whose weights are above or below the healthy range? The statistical adjustment comes because the idea is to keep factors like age, smoking and gender the same and ask what would happen if only weight was changed.
The message, Williamson said, is that perhaps people ought to take other factors into consideration when deciding whether to worry about the health risks of their weight.
Dr. Barry Glassner, a sociology professor at the University of Southern California who has scrutinized the obesity data, had a different message.
"The take-home message from this study it seems to me is unambiguous," he said. "What is officially deemed overweight these days is actually the optimal weight."
NEW YORK People who are overweight have a lower death risk than those of normal weight, federal researchers in the United States will report Wednesday in the newest and most comprehensive study of the impact of obesity.
The researchers, statisticians and epidemiologists from the Centers for Disease Control and the National Cancer Institute, also found that the risks of obesity were not apparent until people became extremely obese, a group that constitutes only 8 percent of Americans. But being very thin - even though the thinness was not caused by disease - also caused a slight increase in the death risk the researchers report.
The new study, which others said is the most rigorous yet, took into account such factors as smoking, age, race and alcohol consumption in a sophisticated statistical analysis derived from a well-known method that has been used to predict cancer risk.
It also used the federal government's own definitions of weight categories that measure fatness according to body mass index, an estimate of weight for height.
For example, people 173 centimeters tall, or 5 feet 8 inches, and weighing less than 55 kilograms, or 122 pounds, are underweight. If they weighed from 55 kilograms to 74 kilograms, their weight would be normal. They would be overweight if their weight was 74 to 88 kilograms. And if they weighed more than 88 kilograms, they would be obese.
In the new study, nearly all the death risk from obesity occurred in the heaviest of the obese, like 173-centimeter person weighing more than 104 kilograms.
But the findings are unexpected and researchers are reacting with a full gamut of responses. Some see the report as a long-needed reality check on what they see as the nation's near-hysteria over fat.
"I love it," said Dr. Steven Blair, who is president and chief executive of the Cooper Institute, a nonprofit research and educational organization in Dallas that focuses on preventive medicine.
Blair, whose data indicate that fitness is more important than fatness, added: "There are people who have made up their minds that obesity and overweight are the biggest public health problem that we have to face. These numbers show that maybe it's not that big."
Others said they simply did not believe the findings. Dr. Joann Manson, chief of preventive medicine at Harvard's Brigham and Women's Hospital, pointed to Harvard's own study of nurses that found mortality risks in being overweight and even greater risks in being obese. "We can't afford to be complacent about the epidemic of obesity," she said.
Dr. Mark Mattson a rail-thin researcher at the National Institute on Aging, who studies caloric restriction as a means to prolong life, said that while the results on very thin people are unexpected, it also is not clear that eating fewer calories means weighing so little. Caloric restriction might extend life, he said, but, he added, "there's certainly a point where you can overdo it with caloric restriction, and we don't know what that point is."
Other statisticians and epidemiologists commented that their methods and data were exemplary and their analysis compelling. They also said that the study's authors, Dr. Katherine Flegal, Dr. David Williamson, Dr. Barry Graubard and Dr. Mitchell Gail, were highly regarded and experienced scientists.
"This is a well known group, and I thought their analysis and their statistical approaches were very good," said Dr. Barbara Hulka, an emeritus professor of epidemiology at the University of North Carolina.
"This is clearly the best analysis - the best thought out and with the best data - that anyone has presented," said Dr. Daniel McGee Jr., a professor of statistics at Florida State University.
The study did not explain why overweight appears best as far as mortality is concerned. But one of the authors, Williamson, of the Centers for Disease Control and Prevention, said it may be because most people die when they are over 70, and having a bit of extra fat appears to be protective. "It's called the obesity paradox," Williamson said. But, he said, while the paradox is real, the reasons are speculative. "It's raw conjecture."
But, the investigators said, it also is possible that obesity and overweight are less of a health risk than they used to be.
In a paper published in the same issue of the Journal of the American Medical Association, Williamson and his colleagues report that high blood pressure and high cholesterol levels are less prevalent now then they were 30 or 40 years ago, and fatter people made the greatest improvements in controlling these conditions that can lead to heart disease. People are also smoking less. Diabetes remains the same, however, afflicting about 4 percent of people of normal weight, 6 percent of those who are overweight, and 14 percent of the obese.
The new study comes just 13 months after different researchers from the Centers from Disease Control and Prevention published a paper in the same journal and signed by the center's director, Dr. Julie Gerberding, warning that obesity and overweight were causing an extra 400,000 deaths a year and that soon excess weight was going to overtake smoking as the nation's leading preventable cause of premature death.
Now, according to the current study, obesity is causing about 111,000 extra deaths, but overweight is preventing about 86,000 deaths that would have been expected if those overweight people were in the normal weight range. And underweight is causing about 34,000 deaths a year.
Dr. Donna Stroup, the director of the Center for Disease Control's coordinating center for health promotion, speaking for the agency, did not take issue with the new figures. "From a scientific point of view, they are a step forward," she said. But, she added, the new analysis looks only at how long people live, not at the quality of their lives.
"Mortality really only represents the tip of the iceberg of the magnitude of the problem," Stroup said.
Estimating deaths due to obesity or overweight is a statistical challenge, the study investigators said. The idea is to determine, for each person in the population, what would be their risk of dying if you could move their weight to a normal weight.
For people whose weight is already in that range there would be no change in the risk of dying, of course. The question is, What happens to the risk for people whose weights are above or below the healthy range? The statistical adjustment comes because the idea is to keep factors like age, smoking and gender the same and ask what would happen if only weight was changed.
The message, Williamson said, is that perhaps people ought to take other factors into consideration when deciding whether to worry about the health risks of their weight.
Dr. Barry Glassner, a sociology professor at the University of Southern California who has scrutinized the obesity data, had a different message.
"The take-home message from this study it seems to me is unambiguous," he said. "What is officially deemed overweight these days is actually the optimal weight."
See more of the world that matters - click here for home delivery of the International Herald Tribune.
