From The October 2001 Issue of Nutrition Science News

Obesity May Cause Asthma

Obesity, a risk factor for many medical conditions, including heart disease and diabetes, is now believed to contribute to asthma onset as well. More than 5 percent of Americans have asthma, and its prevalence mysteriously increased 38 percent from 1980 to 1990.

Silva Young, M.D., an epidemiologist with the U.S. Navy, and her colleagues conducted a controlled study on 1,000 people, ages 17 to 96, who belonged to a military health maintenance organization in the Northwest. She found that people with asthma were more likely to be preobese—defined as having a body mass index (BMI), a measure of body fatness, between 25 and 30—or obese, with a BMI greater than 30. The higher the BMI, the greater the asthma risk. People with a BMI of 35 or more were twice as likely to have asthma as people with a BMI less than 25.

It is not certain which comes first, excess fat or the breathing problem. However, the researchers think it is more likely that obesity causes bronchospasm or alters immune function, which leads to respiratory hyperreactivity. Obesity may also interfere with lung inflation, preventing effective stretching of smooth muscles and causing them to overreact.

—Archives of Internal Medicine
2001 Jul 9;161(13):1603-11.