FROM CSAC, THE CLINICAL AND SCIENTIFIC AFFAIRS COUNCIL OF THE AAPA
This article was written by Gilbert A. Boissonneault, PhD, PA‐C. Contributors included the other members and staff of CSAC 2008–2009: Daniel L. O’Donoghue, PhD, PA‐C, Chair; Anthony E. Brenneman, MPAS, PA‐C; Alison C. Essary, MHPE, PA‐C; Michelle Lynn Heinan, EdD, PA‐C; Marie‐Michèle Léger, MPH, PA‐C; Robert McNellis, MPH, PA; and Eileen M. Van Dyke, MPS, PA‐C. The manuscript was edited by Sarah Zarbock, PA‐C.
>WHO SHOULD READ THIS?
All physician assistants, especially those working in primary care, cardiology, endocrinology, and surgical specialties such as bariatric surgery.
>WHAT IS THE EXTENT OF THE PROBLEM?
The National Health and Nutrition Examination Surveys (NHANES) have tracked an increase in overweight and obese persons in the United States from 1976 through 2006.1 The rates of adult obesity in the United States have doubled between 1976 and 2004, and they have tripled among American children. The most recent estimates are that 190 million Americans are overweight or obese, with 34.1% of the adult population being overweight and 32.9% being obese. For children, overweight prevalence in 2003–2004 was 13.9% for children aged 2 to 5 years, 18.8% for children aged 6 to 11 years, and 17.4% for children aged 12 to 19 years. All these rates increased over the past 30 years. While weight reduction has been a pub‐lic health priority, the prevalence of overweight and obesity represents a continuing public health failure for all states.
>WHY IS THIS IMPORTANT?
Obesity is associated with increased morbidity and mortality related to many health conditions and represents the second leading cause of preventable disease in this country.2,3 Hypertension, dyslipidemia, coronary heart disease, stroke, some cancers, and complications associated with type 2 diabetes are on the list.2 Many of the cardiovascular consequences that are seen in adults begin as abnormalities.4 Overweight children are at risk for type 2 diabetes, particularly among certain subpopulations such as African‐Americans and Hispanics.2
>WHAT ARE THE METHODS TO ASSESS OBESITY?
Total body fat and body fat distribution are estimated by surrogate indicators such as body mass index (BMI) and waist circumference (WC) (see Table 1). The relative risk for all causes of death increases in persons with a BMI greater than 25 kg/m2; this relationship is stronger for males than for females.5 BMI findings may overestimate body fat content in muscular persons and may underestimate body fat in persons who have lost muscle mass (for example, older adults).
BMI ranges for children and adolescents aged 2 to 18 years are different than those for adults. Children are classified as “at risk for overweight” when their BMI is between the 85th and 95th percentile for their age and they are “overweight” with a BMI greater than the 95th percentile. The BMI tables for children are available from the CDC.6
- To minimize morbidity and mortality, PAs should stress the importance of maintaining body weight within the BMI range of 18.5 to <25 kg/m2.
- Caloric restriction and physical activity should be stressed for all.
- Risk assessment for cardiovascular disease and diabetes should be performed.
- Mediterranean‐type diets and lowcarbohydrate diets may offer significant weight loss and be healthier than other diet types.
- For BMI >35 kg/m2, consider pharmacotherapeutic agents and bariatric surgery, particularly when obesity‐related risks or comorbidities are significant.
Larger WC (greater than 40 inches for men and greater than 35 inches for women) is associated with a 20% higher risk of mortality compared to those with smaller waists, and this is independent of increased BMI.3 Another indicator of central obesity is the waist‐to‐height ratio (WHtR), determined by dividing WC by height in the same units (see Table 2, page 19). The target ratio for this measure is less than 0.5— that is, waist circumference should be less than half the person's height.7 This measure is not affected by gender or age and is associated with cardiovascu‐lar disease (CVD) risk clustering in persons of all ages and both genders.7 WHtR may be a better indicator of abdominal obesity and CVD risk than WC or BMI.8 Consider using WHtR, particularly in persons with significantly shorter or taller height than average.
>WHAT ARE THE CURRENT RECOMMENDATIONS?
Figure. ALGORITHM...Image Tools
Mediterranean or low‐carbohydrate diets appear to be more effective at maintaining sustainable weight loss than the American Heart Association low‐fat diet.9 High‐protein diets may be more effective at promoting weight loss than high‐carbohydrate diets,10 but these differences may be controversial.11 Structured weight loss plans should incorporate a strict food and activity plan with behavioral modification and weekly meetings. Such plans are more effective than self‐help programs.12
Exercise is always a valuable part of a weight loss regimen, particularly when combined with dietary changes,13 and this combination is able to decrease the development of type 2 diabetes in high risk groups14 as well as improve glycemic control, abdominal adiposity, and plasma triglycerides in people with type 2 diabetes.15 Exercise is also effective in sustaining weight loss.16 Duration of exercise appears to be more important than intensity in supporting weight loss.17
Pharmacologic therapies should be combined with calorie restriction, increased physical activity, and careful evaluation before pharmacotherapies are offered. Sibutramine (Meridia), orlistat (Xenical, Alli) and amphetamines (phentermine and diethylpropion) resulted in weight loss ranging from 4 to 10 kg when coupled with dietary restrictions.18 Potential adverse reactions of each medication should be considered: GI disturbances with orlistat; hypertension, tachycardia, and mood disorders (including depression and suicidal ideation) with sibutramine; and hypertension, tachycardia, palpitations, and arrhythmias with the amphetamines, not to mention the potential for abuse.
Bariatric surgery can be the most successful intervention for long‐term weight loss in patients with a BMI of 40 kg/m2 or higher without comorbidities or 35 kg/m2 or higher with comorbidities. Approximately 61.2% of excess weight was lost utilizing bariatric procedures. Individual procedures such as gastric banding, gastric bypass, gastroplasty, and biliopancreatic diversion or duodenal switch resulted in loss of about 50% to 70% of excess weight.19 Regardless of procedure, weight loss was associated with partial, and many cases complete, resolution of diabetes, hyperlipidemia, hypertension, and sleep apnea. The main issues for operative procedures is the mortality of 0.1% for banding and gastroplasty to 1.1% for biliopancreatic diversion or duodenal switch procedures.19
2. Clinical Guidelines on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults: The Evidence Report
. NIH Publication No. 98-4083, September 1998, National Institutes of Health. http://www.nhlbi.nih.gov/guidelines/obesity/ob_gdlns.pdf
. Accessed December 12, 2008.
3. Koster A, Leitzmann MF, Schatzkin A, et al. Waist circumference and mortality. Am J Epidemiol
4. Dietz WH. Health consequences of obesity in youth: childhood predictors of adult disease. Pediatrics
5. Calle EE, Thun MJ, Petrelli JM, et al. Body-mass index and mortality in a prospective cohort of US adults. N Engl J Med
7. Garnett SP, Baur LA, Cowell CT. Waist-to-height ratio: a simple option for determining excess central adiposity in young people. Int J Obes
8. Lee CMY, Huxley RR, Wildman RP, Woodward M. Indices of abdominal obesity are better discriminators of cardiovascular risk factors than BMI: a meta-analysis. J Clin Epidemiol
9. Shai I, Schwarzfuchs D, Henkin Y, et al. Weight loss with a low-carbohydrate, Mediterranean, or low-fat diet. N Engl J Med
10. Skov AR, Toubro S, Ronn B, et al. Randomized trial on protein vs carbohydrate ad libitum fat reduced diet for the treatment of obesity. Int J Obes
11. Farnsworth E, Luscombe ND, Noakes M, et al. Effect of a high-protein, energy-restricted diet on body composition, glycemic control, and lipid concentrations in overweight and obese hyperinsulinemic men and women. Am J Clin Nutr
12. Heshka S, Anderson JW, Atkinson RL, et al. Weight loss with a self-help compared with a structured commercial program: a randomized trial. JAMA
13. Shaw K, Gennat H, O’Rourke P, Del Mar C. Exercise for overweight or obesity. Cochrane Database of Systematic Reviews
. 2006, Issue 4. Art. No.: CD003817. doi:10.1002/14651858.CD003817.pub3.
14. Orozco LJ, Buchleitner AM, Gimenez-Perez G, et al. Exercise or exercise and diet for preventing type 2 diabetes mellitus. Cochrane Database of Systematic Reviews
. 2008, Issue 3. Art. No.: CD003054. doi:10.1002/14651858.CD003054.pub3.
15. Thomas DE, Elliott EJ, Naughton GA. Exercise for type 2 diabetes mellitus. Cochrane Database of Systematic Reviews
. 2006, Issue 3. Art. No.: CD002968. doi:10.1002/14651858. CD002968.pub2.
16. Jakicic JM, Marcus BH, Lang W, Janney C. Effect of exercise on 24-month weight loss maintenance in overweight women. Arch Intern Med
17. Jakicic JM, Marcus BH, Gallagher KI, et al. Effect of exercise duration and intensity on weight loss in overweight, sedentary women: a randomized trial. JAMA
18. Ioannides-Demos LL, Proietto J, McNeil JJ. Pharmacotherapy for obesity. Drugs
19. Buchwald H, Avidor Y, Braunwald E, et al. Bariatric surgery: a systematic review and meta-analysis. JAMA
© 2009 Lippincott Williams & Wilkins, Inc.