教えるのは、あなたが望む専門分野の現役ビジネスマン達。

Metabolic syndrome, also known as Syndrome X, is not a disease. The term refers to a group of risk factors that increase a person’s chance for heart disease, diabetes, stroke and other health problems. For example, people with metabolic syndrome are twice as likely to develop heart disease and five times as likely to develop diabetes compared to people without metabolic syndrome¹.

The American Heart Association and the U.S. National Heart, Lung, and Blood Institute define metabolic syndrome as the presence of three or more of the following components²:

• Elevated waist circumference (men: ≥ 102 cm, women: ≥ 88 cm)
• Elevated triglycerides (≥ 150 mg/dL)
• Reduced HDL cholesterol (men: ≤ 40 mg/dL, women: ≤ 50 mg/dL)
• Elevated blood pressure (≥ 130/85 mm Hg)
• Elevated fasting glucose (≥ 100 mg/dL)

Despite the high prevalence of metabolic risks in Asians, obesity is relatively low. Therefore, it has been suggested that a waist-to-height (W/Ht) ratio ? 0.5 is a more effective index than waist circumference in identifying metabolic syndrome³. Similarly, although the World Health Organization (WHO) defines obesity as body mass index (BMI) > 30.0 kg/m2, researchers have proposed that obesity in Japanese be defined as BMI > 25.0 kg/m2 based on studies evaluating high risk groups for cardiovascular disease in Japan⁴.

According to the Japanese Health, Labor and Welfare Ministry, an estimated 13 million people in Japan suffer from metabolic syndrome and another 14 million are estimated to be at risk of getting it⁵. In the U.S., the National Institutes of Health’s National Heart, Lung and Blood Institute reports that 47 million Americans, or nearly one out of six people, have metabolic syndrome⁶.

Metabolic syndrome is closely linked to people who are overweight or obese and to a lack of physical activity. Insulin resistance, a condition in which the body does not use insulin properly, is another cause. It is believed that genetics and older age are other important underlying causes⁷.

Metabolic syndrome can be prevented or delayed with lifestyle changes such as exercising regularly, eating a healthy diet, losing weight and avoiding tobacco. Sometimes the individual components of metabolic syndrome are treated with blood pressure, cholesterol and/or diabetes medications⁸.

Discussion questions

1. Please summarize the article. What is the main point of the article?
2. What is metabolic syndrome?
3. Should the same definitions of elevated waist circumference and obesity apply to Americans and Asians? How should obesity be measured in Japan?
4. How many people have metabolic syndrome in Japan? In the U.S.?
5. What causes metabolic syndrome?
6. How can metabolic syndrome be prevented?
7. Is it possible to treat metabolic syndrome?

References:

1. What is metabolic syndrome. U.S. National Institutes of Health’s National Heart, Lung and Blood Institute (accessed 29 October 2007)
2. Metabolic syndrome, American Heart Association. (accessed 29 October 2007)
3. Hsieh SD and Muto T. Metabolic syndrome in Japanese men and women with special reference to the anthropometric criteria for the assessment of obesity: Proposal to use the waist-to-height ratio. Preventive medicine. Vol. 42, issue 2, February 2006, pages 135-139. (accessed 29 October 2007)
4. Ota T, Takamura T, Hirai N, Kobayashi K. Letter: Observations to Preobesity in World Health Organization classification involves the metabolic syndrome in Japanese. Diabetes Care. 25:1252-1253, 2002. (accessed 29 October 2007)
5. 13 million suffer from metabolic syndrome, study indicates. Japan Times. 9 May 2006. (accessed 29 October 2007) [Note: the study examined men with waists measuring ≥ 85 cm and women with waists measuring ≥ 90 cm]
6. What is metabolic syndrome. U.S. National Institutes of Health’s National Heart, Lung and Blood Institute (accessed 29 October 2007)
7. What is metabolic syndrome. U.S. National Institutes of Health’s National Heart, Lung and Blood Institute (accessed 29 October 2007)
8. Metabolic syndrome health center. WebMD. (accessed 29 October 2007)

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