By: National Heart, Lung, and Blood Institute
Date: June 3, 1998
Source: National Heart, Lung, and Blood Institute of the National Institutes of Health. "Statement on First Federal Obesity Clinical Guidelines." June 3, 1998. Available online at ; website home page: http://www.nih.gov (accessed April 22, 2003).
About the Organization: The origins of the National Heart, Lung, and Blood Institute extend back to June 16, 1948, when President Harry S. Truman signed the National Heart Act. Later, Surgeon General Leonard Scheele established the National Heart Institute (NHI). Twenty-four years later, through section 413 of the National Heart, Blood Vessel, Lung, and Blood Act (P.L. 92-423), Congress required the NHI to expand. The NHI was renamed the National Heart, Lung, and Blood Institute (NHLBI). The NHLBI is a part of the National Institutes of Health (NIH).
Obesity was a major health story in the 1990s. Worldwide, the numbers of obese people increased beginning in 1980 and continuing through the 1990s. In some countries, including the United States, over half the adult population was estimated to be overweight or obese. Certain women and ethnic groups are particularly disposed to become overweight. Eastern Europeans, people from the Mediterranean region, American Indians, Hispanic Americans, Pacific Islanders, and African American women have some of the highest rates of obesity in the world.
The 1998 obesity guidelines issued by the National Heart, Lung, and Blood Institute (NHLBI) were the first such guidelines on obesity issued for doctors. In the past, doctors, along with the rest of society, tended to view obesity as a cosmetic problem or a failure of self-discipline.Doctors would treat the symptoms of obesity, such as diabetes, stroke, or coronary artery disease, but obesity itself was not considered a disease. The NHLBI guidelines changed this view by directing and guiding physicians to treat obesity as a disease itself.
The guidelines included a method that doctors should use to determine whether or not a patient was obese—the Body Mass Index (BMI), the best and most widely used measure of obesity. At a meeting in 1997, the World Health Organization (WHO) agreed that BMI would be used as the worldwide standard for obesity. A BMI of 30 or greater indicates obesity.
Doctor intervention was determined to be a key factor in effective treatment of obesity. In a vacuum of medical advice, many overweight and obese people turned to commercial weight-loss programs, but they were also vulnerable to "lose weight quick schemes" and treatments. It was found that obese patients who received advice from a doctor or other medical professional were more apt to lose weight.
Since obesity was deemed a disease, doctors were advised in ways to treat it. The recommended treatment included an individualized program of physical activity, moderate food intake, counseling, and prescription medications when necessary. Obesity medications generally are appetite-suppressant drugs, which act by increasing the levels of serotonin, one of the chemical messengers in the brain. Another type of anti-obesity medication was approved by the Food and Drug Administration (FDA) in 1999. The new drug works by reducing the body's ability to absorb dietary fat.
Many public health officials and organizations have tried to warn the public about the dangers of obesity. One of the strongest warnings came from the surgeon general, who stated that a failure to address overweight and obese Americans "could wipe out some of the gains we've made in areas such as heart disease, several forms of cancer, and other chronic health problems." The public health community has launched informational campaigns focusing on the medical consequences of extreme weight gain. All of this seems to have had little effect; obesity rates in the United States have continued to rise. In 2000, 30.5 percent of adults were considered obese, compared to 22.9 percent in 1994.
Medical professionals are worried about obese children. Childhood obesity is blamed on eating frequent meals away from home, a sedentary lifestyle, and high-fat and high-calorie diets. Childhood obesity produces a special set of problems for the health field. Weight patterns for children more often than not are carried into adulthood, where it is even harder to lose weight. But diabetes is a bigger concern. Obesity induces type 2 diabetes mellitus, a metabolic disorder leading to high blood sugar levels and an inability to properly metabolize carbohydrates, proteins, and fats. Obese children who develop diabetes may lose weight, but they will never be able to lose diabetes once they have it. Additionally, obese children are at a greater risk for psychological problems. Obesity and its complications threaten to overwhelm the health care system in the near future.
The National Heart, Lung, and Blood Institute guidelines classified obesity as a metabolic disease. Research into the molecular causes of obesity have provided some insights into the disease. So far five different genes, ten hormones, and imbalances in the neurotransmitter serotonin have been implicated in causing people to eat excessively. Many scientists are looking at evolution to provide clues as to why humans are becoming increasingly overweight. They theorize that a survival mechanism that benefited humans millions of years ago may be causing more people to be overweight now. Ancient humans who survived through periods of food shortages were those who were able to use calories more efficiently and store fat for future use. In addition, humans have strong biological signals to consume food and weak signals for when to stop.
Primary Source: "Statement on First Federal Obesity Clinical Guidelines"
SYNOPSIS: The following guidelines issued by the National Heart, Lung, and Blood Institute alerted the medical community to the need to treat obesity as a medical condition and described the Body Mass Index.
The first Federal guidelines on the identification, evaluation, and treatment of overweight and obesity in adults are scheduled to be released on June 17 by the National Heart, Lung, and Blood Institute (NHLBI), in cooperation with the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). Due to a premature release in the news media of erroneous information about the guidelines, some of the key recommendations of the report are being released now. The intent is to ensure that accurate information about the guidelines is available to the public.
The guidelines were developed by a 24-member expert panel chaired by Dr. F. Xavier Pi-Sunyer, director of the Obesity Research Center, St.Luke's/Roosevelt Hospital Center in New York City. They are currently being reviewed by 115 health experts at major medical and professional societies. The NHLBI is in the process of receiving comments and endorsements from these experts.
Based on the most extensive review of the scientific evidence on overweight and obesity conducted to date, these clinical practice guidelines for physicians present a new approach for the assessment of overweight and obesity and establish principles of safe and effective weight loss.
According to the guidelines, assessment of overweight involves evaluation of three key measures—body mass index (BMI), waist circumference, and a patient's risk factors for diseases and conditions associated with obesity.
The guidelines' definition of overweight is based on research which relates body mass index to risk of death and illness. The expert panel that developed the guidelines defined overweight as a BMI of 25 to 29.9 and obesity as a BMI of 30 and above, which is consistent with the definitions used in many other countries. BMI describes body weight relative to height and is strongly correlated with total body fat content in adults. According to the guidelines, a BMI of 30 is about 30 pounds overweight and is equivalent to 221 pounds in a 6 person and to 186 pounds in someone who is 5 6 .
The panel recommends that BMI be determined in all adults. People of normal weight should have their BMI reassessed in 2 years.
According to a new analysis of the National Health and Nutrition Examination Survey (NHANES III), as BMI levels rise, average blood pressure and total cholesterol levels increase and average HDL or good cholesterol levels decrease. Men and women in the highest obesity category have five times the risk of hypertension, high blood cholesterol, or both compared to individuals of normal weight.
The guidelines recommend weight loss to lower high blood pressure, to lower high total cholesterol and to raise low levels of HDL or good cholesterol, and to lower elevated blood glucose in overweight persons with two or more risk factors and in obese persons who are at increased risk. They recommend that overweight patients without risk factors work on maintaining current weight or preventing further weight gain.
According to the guidelines, 97 million American adults—55 percent of the population—are now considered overweight or obese. These individuals are at increased risk of illness from hypertension, lipid disorders, type 2 diabetes, coronary heart disease, stroke, gallbladder disease, osteoarthritis, sleep apnea and respiratory problems, and certain cancers. The report of the guidelines also notes that obesity is associated with higher death rates and, after smoking, is the second leading cause of preventable death in the U.S. today. The total costs attributable to obesity-related disease approaches $100 billion annually.
In addition to measuring BMI, health care professionals can assess an individual patient's risk status through evaluating risk factors for obesity, such as elevations in blood pressure or family history of obesity-related disease. At a given level of overweight or obesity, patients with additional risk factors are considered to be at higher risk for health problems, requiring more intensive therapy and modification of any risk factors.
Physicians are also advised to determine waist circumference, which is strongly associated with abdominal fat. Excess abdominal fat is an independent predictor of disease risk. The panel concluded that waist circumference is a better marker of abdominal fat and a better predictor of disease risk than the current method of calculating the waist-to-hip ratio. A waist circumference of over 40 inches in men and over 35 inches in women signifies increased risk in those who have a BMI of 25 to 34.9.
The new guidelines stress that there are no new or magic cures for weight loss. The most successful strategies for weight loss include calorie reduction, increased physical activity, and behavior therapy designed to improve eating and physical activity habits. The guidelines advise physicians to have their patients try lifestyle therapy for at least 6 months before embarking on physician-prescribed drug therapy. Weight loss drugs approved by the FDA for long-term use may be tried as part of a comprehensive weight loss program that includes dietary therapy and physical activity in carefully selected patients (BMI 30 without additional risk factors, BMI 27 with two or more of the following risk factors—diabetes, high blood pressure, high blood cholesterol, and sleep apnea) who have been unable to lose weight or maintain weight loss with conventional nondrug therapies. Drug therapy can also be used during the weight maintenance phase of treatment. However, drug safety and effectiveness beyond one year of total treatment have not been established.
When published, Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults will be distributed to primary care physicians in the U.S. as well as to other interested health care practitioners. It will also be available on the NHLBI website—http://www.nhlbi.nih.gov/nhlbi/ on June 17.
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