LOS ANGELES, April 6 (Xinhua) -- Overweight and obese individuals have a 50-percent higher risk for asthma than normal-weight people, according to a new study published in the April issue of the American Journal of Respiratory and Critical Care Medicine.

    Researchers at the National Jewish Medical and Research Center (NJMRC) in Denver pored over prior data on the body mass indices (BMI) -- measurements of body fat based on the height and weight -- of adult asthma patients.

    They looked at data from seven prior studies conducted between 1966 and 2006 in the United States, Canada, and Europe. Together, these studies had looked into BMI and asthma in more than 333,000 severely asthmatic patients.

    During data review, the researchers adopted standard BMI yardsticks, which define "normal weight" as having a BMI of under 25, "overweight" as a BMI between 25 and 29, and "obese" as a BMI more than 30. For example, a person who is 5 feet 6 inches tall and weighs 145 pounds has a BMI of 22.

    The odds of developing asthma grew by 50 percent among patients with a BMI of 25 and up, and the risk climbed as the pounds piled on, the study found.

    Women and men appeared to be equally susceptible to the weight-asthma association, they added.

    Based on the findings, the researchers believe asthma should be added to the long list of diseases -- including diabetes, sleep apnea, stroke, cardiovascular illness, and arthritis -- for which excess weight is a risk factor.

    The study argues that public health efforts to control asthma should therefore emphasize the importance of healthy weight management.

    According to the U.S. National Institutes of Health, asthma is an incurable but usually controllable chronic disease involving inflammation and narrowing of the airways that carry oxygen into and out of the lungs.

    The disease typically provokes recurrent wheezing, coughing, and a hypersensitivity to allergies and affects approximately 20 million Americans, including 9 million children.