Weight Control and Cardiovascular Risk Reduction

by James O’Keefe, Jr, MD (Director of Preventive Medicine, Mid-America Heart Institute, Kansas City, MO), Mark S. Freed, MD (Cardiologist, President of Physicians' Press), and Christie Ballantyne, MD (Clinical Director, Section of Atherosclerosis, Baylor College of Medicine)

Overview

An estimated 55% of adults in the United States are overweight or obese, conditions associated with increased morbidity from hypertension, dyslipidemia, type 2 diabetes, coronary artery disease, stroke, gallbladder disease, osteoarthritis, sleep apnea, respiratory problems, and cancer (endometrial, breast, prostate, and colon). Higher body weights also increase the risk for all-cause mortality. Weight control improves blood pressure, triglycerides, LDL and HDL cholesterol, blood glucose, and hemoglobin A1c levels in type 2 diabetics. NHLBI guideline recommendations for the identification, evaluation, and treatment of overweight and obesity in adults are summarized below, and detailed in Obesity Res 1998;6:595[51S-209S] and Arch Intern Med 1998;158:1855.

All patients should be classified by body mass index (BMI) to assess overweight/obesity, and by waist circumference to assess abdominal fat content.   Abdominal (visceral) fat content, which identifies increased risk for coronary artery disease independent of body-mass index (BMI), and waist circumference are then used to assess disease risk (Table 1).

Evaluation of Obesity

Efforts should be made to review patient medications to see if adjustments/substitutions can be made to drugs associated with weight gain, such as antidepressants, glucocorticoids, phenothiazines, lithium, cyproheptadine, sulfonylureas, and insulin.  The patient should also be examined for features suggestive of Cushing’s syndrome (truncal obesity, moon facies, ecchymosis, muscle atrophy, edema, striae, acne, hirsutism, osteoporosis, glucose intolerance, hypokalemia) or hypothyroidism (weakness, fatigue, cold intolerance, constipation, dry skin, bradycardia, hyporeflexia). Patients with suspected sleep apnea (cessation of breathing during sleep, snoring, restless sleep, excessive daytime sleepiness ± headaches, memory impairment) should be referred to a specialist.

Treatment of Obesity

The treatment of overweight/obesity requires a combination of diet, physical activity, and behavior modification; patients requiring additional measures may benefit from drug therapy and weight loss surgery (refractory cases). Total caloric intake and energy expenditure (physical activity) should be adjusted to achieve and maintain a desirable body weight (BMI 21-25 kg/m²) and waist circumference (< 102 cm in men; < 88 cm in women). A reasonable initial goal is to reduce body weight by 10% over 6 months; this typically requires calorie deficits of 300 kcal/d in patients with BMIs of 27-35, and 500-1000 kcal/d (1-2 lb/wk) in patients with BMIs > 35. Further weight loss can be considered once this goal is achieved. Calorie deficits are best accomplished through a combination of dietary restriction and physical activity.

Diet. Calorie deficits of 500-1000 kcal/d usually require a diet providing 1000-1200 kcal/d for women and 1200-1500 kcal/d for men. Low-carbohydrate and other "fad" diets may facilitate early weight loss, but are difficult to maintain, frequently unhealthy, and often result in diminished self-esteem as weight is inevitably regained. The best approach to diet is to eat smaller portions of a well-rounded (e.g., Mediterranean-style  diet (p. 30).

Physicial Activity.  Increased physical activity is an essential component of an effective weight loss program, leading to calorie deficits and improvements in cardiovascular risk factors, mood, and self-esteem. Walking is an excellent option for obese patients, initially at 10 minutes per day 3 times weekly and building to 30-45 minutes per day on most or all days of the week. Ordinary household tasks can also lead to substantial calorie deficits. Examples of calories burned in 1 hour for a 130-pound woman and a 180-pound man include cleaning windows (208/288), gardening (416/576), mowing the lawn (351/486), painting the house (273/378), washing the car (195/270), and dancing (208/288). A stress test should be considered prior to initiating an exercise program in individuals with known cardiovascular or pulmonary disease, and for sedentary males > 40 years or females > 50 years with 2 or more cardiovascular risk factors (hypertension, dyslipidemia, diabetes mellitus, smoking, family history).

Behavior Therapy.  It is essential to communicate encouragement, support, and understanding in order to optimize compliance. Other useful behavior modification techniques include self-monitoring (food consumption and exercise), stress management (coping strategies, relaxation techniques, drug therapy), problem solving (coping with urges and cravings), contingency management (rewarding achieved goals), cognitive restructuring (changing unrealistic goals and improving self-image), and social support (positive reinforcement).

Drug Therapy.  Pharmacotherapy can be a useful adjunct to diet, physical activity, and behavior modification, both for weight loss and to prevent weight regain, but is unlikely to be effective as monotherapy. Drug therapy is especially useful for patients with BMIs > 30, or > 27 in the presence of other risk factors (hypertension, dyslipidemia, type 2 diabetes, coronary artery disease, sleep apnea). Antiobesity drugs approved by the FDA are shown in Table 2.

Weight Loss Surgery. Gastrointestinal surgery (gastric restriction or bypass) should be reserved for motivated patients with extreme obesity (BMI > 40 or > 35 with comorbid conditions) despite nonsurgical intervention. Lifelong medical monitoring and nutritional supplementation with minerals and vitamins lost through malabsorption are required.

© 2009 Jones and Bartlett Publishers