Obesity – The New Epidemic
Dr. Carabin is the President and Medical Director of Women’s Health Sciences Institute, Inc., a not-for-profit organization, located in Vero Beach, FL.
United States is currently plagued by a new epidemic – obesity. According to the National Health and Nutrition Examination Survey (NHANES) 1999-2000, 64 percent of American adults are either overweight or obese. Overweight refers to an excess of body weight compared to agreed upon standards. Obesity refers specifically to having an abnormally high proportion of body fat.[i] Obesity occurs when a person consumes more calories than are burned, resulting in the deposition of fat. There is no single cause of human obesity; several factors can be involved ranging from genetic, to behavioral, and physiological.
Most methods in ascertaining the condition of being overweight or obesity are based on the relation between height and weight; others are based on measurements of body fat. The most commonly used method today for measuring overweight or obesity is the body mass index (BMI). BMI is a calculation based on height and weight, and it is not gender-specific. The mathematical formula for calculating the BMI is:
BMI = weight (kg) / height squared (m2)
Obesity is found worldwide. In the United States, overweight/obesity have become a problem over the last several decades, as demonstrated by their steadily increased prevalence affecting all ages, genders, and socioeconomic status.[ii] For example, the prevalence of obesity (BMI[iii] > 30) more than doubled from 13.3 to 30.9 percent between 1960 and 2000, while the prevalence of extreme (morbid) obesity (BMI > 40) increased from 2.9 to 4.7 percent between 1988 and 2000.[iv]
Until recently, health care providers often relied on weight-for-height tables that have a range of acceptable weights for a person of a given height. Unfortunately, there are many versions of these tables, all with different weight ranges. Therefore, in an effort to update old and inaccurate methods in ascertaining overweight or obesity, many Government agencies and health organizations are estimating weight status using data from a series of cross-sectional surveys called the National Health Examination Surveys (NHES) and the National Health and Nutrition Examination Surveys (NHANES). An Expert Panel convened by the National Heart, Lung, and Blood Institute (NHLBI) in cooperation with the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), both part of the National Institutes of Health (NIH), identified overweight as a BMI of 25 – 29.9 kg/m², and obesity as a BMI of 30 kg/m² or greater.[v]
While an individual’s weight is important, so is the location of body fat. Fat distribution is different between sexes. In general, women collect fat on their hips and buttocks, while men build up fat around their bellies. It has been shown that excess abdominal fat is an independent predictor of risk factors and medical problems associated with obesity if the waist measurement for women exceeds 35 inches and 40 inches for men.[vi]
Obesity is more than a cosmetic problem. It is a major chronic disease associated with numerous comorbidities including, but not limited to liver disease, gout, osteoarthritis, respiratory difficulties (i.e., sleep apnea, shortness of breath), reproductive problems in women, psychological problems (i.e., depression), and increased surgical risk. Rapidly growing medical conditions believed to be associated with obesity and overweight are hypertension (HTN), high cholesterol and triglycerides (Table 1), diabetes, and cancer.
Table 1. Prevalence of high cholesterol and hypertension in obese adults in the U.S. (adapted from Statistics Related to Overweight and Obesity, 2003)[vii]MalesFemalesBMIPrevalence of ↑ cholesterol (%)Prevalence of HTN (%)BMIPrevalence of ↑ cholesterol (%)Prevalence of HTN (%)< 2513.014.9< 2513.415.2> 25 <2719.122.1> 25 <2730.527.7> 27 <3021.627> 27 <3029.632.7> 3022.041.9> 3027.037.8BMI = body mass index; HTN = hypertension
In the U.S., approximately 17 million people suffer with type 2 diabetes.[viii] Among those diagnosed with type 2 (noninsulin-dependent) diabetes, 67 percent have a BMI > 27, and 46 percent have a BMI > 30. An estimated 70 percent of diabetes risk in the U.S. can be attributed to excess weight.[ix] Obesity is also associated with higher rates of developing certain types of cancer, such as breast, uterus, cervix, ovaries, or gallbladder (observed in obese women), and prostate, colon, or rectum (in obese men).
In addition to suffering from a host of chronic medical conditions, the life expectancy of obese (BMI > 30) individuals is also affected, with a 50 to 100 percent increased risk of death from all causes, compared with normal-weight individuals (BMI 20 – 25). However, most of the increased risk is due to cardiovascular causes.[x] Life expectancy of a moderately obese person could be shortened by 2 to 5 years – or by as much as 20 years for a morbidly obese individual. Approximately 400,000 adult deaths each year are related to obesity in the United States.[xi]
Approaches to treating obesity are complex and challenging, primarily due to the multitude of etiologies leading to this condition. Scores of treatments have been tried, alone or in combination, including decreased caloric intake, increased physical activity, fad diets (i.e., low-carb), behavior modification, the use of the OTC and prescription medications, and surgery. Bariatric[xii] surgery is reserved for the morbidly obese, who comprise approximately 5 percent of the U.S. population.[xiii] Recommendations for treatment are now focusing on 10 percent weight loss and helping patients with long-term maintenance of weight loss.[xiv]
Americans spent approximately $33 billion[1] in the early 1990’s on all efforts at weight loss and/or weight maintenance, including low-calorie/low-fat foods, artificially sweetened products, and memberships at fitness centers.[xv] For the most part, these efforts have been unsuccessful, as the medical expenditures resulting from treating obesity-related diseases have grown significantly. In the United States, a substantial economic toll estimated at $117 billion is attributed to obesity for the year 2003.[xvi]
Uncertain as to the future of the current generation and those to follow, healthcare agencies and national research facilities have embarked on a campaign to aggressively address the obesity problem. For example, the FDA is in the process of revising portion sizes, believed to be one major culprit in causing this problem. NIH has published a strategic plan for obesity research,[xvii] and is encouraging research addressing all forms of possible treatment, from traditional to non-conventional. The challenge for industries (i.e., pharmaceutical, food and dietary supplement) is to find the “miracle” cure, while providing safe products to consumers. With the pharmaceutical industry has been unsuccessful in developing the “wonder drug,” dietary supplement manufacturers are interested in marketing new mixtures and potions to promote weight loss. Although a number of treatments are widely used, limited scientific data may not support some of the claims. Nevertheless, several of these products have plausible mechanisms of action, necessitating further research. While animal and in vitro studies are helpful in identifying a mechanism of action, efficacy can be demonstrated in humans only through clinical studies.[xviii] Such studies are a requirement for claim substantiation. Various avenues need to be explored in an effort to discover a reliable treatment that will have an immediate impact on a very “large” problem.
[1] This number is estimated to be significantly higher a decade later.
References
[i] Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults. National Institutes of Health, National Heart, Lung, and Blood Institute. June 1998.
[ii] Mokdad AH, Ford ES, Bowman BA, Dietz WH, Vinicor F, Bales VS, Marks JS. Prevalence of obesity, diabetes, and obesity-related health risk factors, 2001. Journal of the American Medical Association. 2003;289(1):76-79.
[iii] Body Mass Index
[iv] Flegal KM, Carroll MD, Ogden CL, Johnson CL. Prevalence and trends in obesity among US adults, 1999-2000. Journal of the American Medical Association. 2002;288:1723-1727.
[v] Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults. National Institutes of Health, National Heart, Lung, and Blood Institute. June 1998.
[vi] Ibid.
[vii] Ibid.
[viii] Centers for Disease Control and Prevention. National diabetes fact sheet: General information and national estimates on diabetes in the United States, 2000. Atlanta, GA: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, 2002.
[ix] National Institute of Diabetes and Digestive and Kidney Diseases. Diabetes Prevention Program Meeting Summary. August 2001. Diabetes Mellitus Interagency Coordinating Committee.
[x] Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults—The Evidence Report. National Institutes of Health. Obesity Research. 1998;6 (suppl)2:51S-209S.
[xi] Fontaine KR, Redden DT, Wang C, Westfall AO, Allison DB. Years of life lost due to obesity. Journal of the American Medical Association. 2003;289(2):187-93.
[xii] That branch/sub-specialty of medicine concerned with the management (prevention or control) of obesity and allied diseases.
[xiii] Buchwald H et al. Bariatric surgery. Journal of the American Medical Association. 2004;292:1724-1737.
[xiv] Statistics Related to Overweight and Obesity. U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES, National Institutes of Health; NIH Publication No. 03-4158, July 2003; e-text posted: July 2003.
[xv] Colditz GA. Economic costs of obesity. American Journal of Clinical Nutrition. 1992;55:503-507s.
[xvi] Statistics Related to Overweight and Obesity. U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES, National Institutes of Health; NIH Publication No. 03-4158, July 2003; e-text posted: July 2003.
[xvii] Strategic plan for NIH obesity research. NIH Publication No. 04-5493. August 2004.
[xviii] For an overview of conducting clinical trials, see Ioana G. Carabin, The Clinical Aspects of Claim Substantiation, FDLI Update, May/June 2004, at 25; Ioana G. Carabin, The Clinical Aspects of Claim Substantiation. Clinical Trial Costs, FDLI UPDATE, July/August 2004, at 39.