According to some authorities, obesity is not an independent risk factor for coronary heart disease. However, upper-body obesity is associated with glucose intolerance, hypertriglyceridemia and hypertension. These conditions coexist more commonly than by chance, and overall mortality rises with increasing body weight. In a review of the data on these interrelationships, Kaplan proposes that hyperinsulinemia is the key intermediary for the development of coronary heart disease.
In the presence of a positive energy balance and increased androgenic activity, an increase in the deposition of fat occurs within the abdomen and upper body. Intraabdominal fat is associated with increased plasma insulin levels. Hyperinsulinemia may elevate the blood pressure in at least three ways: by reducing urinary sodium and water excretion, by increasing plasma norepinephrine and by the induction of vascular smooth muscle hypertrophy.
The key to preventing coronary heart disease associated with hypertension and hyperinsulinemia may be in preventing upper-body obesity. Upper-body fat, measured by the waist-to-hip ratio, is a better predictor of coronary heart disease mortality than is total body obesity. Persons with upper-body obesity have an "apple" shape rather than a "pear" shape. Upper-body obesity is concentrated in the abdominal area rather than in the gluteal or femoral areas. Typically, the waist-to-hip girth ratio is greater than 0.85.
The author believes that the ratio between the waist and hip circumference should be routinely measured at health examinations. Even in the absence of excess total body weight, a waist-to-hip ratio greater than 0. 85 indicates the need for reduced caloric intake and increased physical activity. For those persons who are obese (defined as greater than 20 percent above ideal body weight), even limited amounts of weight loss may be helpful. (Archives of Internal Medicine, July 1989, vol. 149, p. 1514.)
COPYRIGHT 1990 American Academy of Family Physicians
COPYRIGHT 2004 Gale Group
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Aagenaes syndrome
