Overweight people at asthma risk

Chicago: Obese and overweight people are 50 per cent more likely to get asthma than those of normal weight, suggesting that weight loss could help reduce the number of asthma cases, US researchers said on Monday.

Asthma, an inflammatory disease usually triggered by an allergy, can cause wheezing, coughing and labored breathing that can be life-threatening.

It affects about seven per cent of the US adult population. Obesity and being overweight are far more prevalent, affecting about 65 per cent of US adults.

Both types of ailments are on the rise and a new study suggests the two may be linked.

"Overweight and obesity significantly increases the risk of developing asthma," said Dr. E Rand Sutherland of the National Jewish Medical and Research Center in Denver, Colorado, who wrote the study.

"If you can substantially reduce the amount of overweight or obese people, you might also get a reduction in the number of new cases of asthma," Sutherland said in a telephone interview.

Sutherland and colleagues, writing in the April issue of the American Journal of Respiratory and Critical Care Medicine, said a significant reduction in the incidence of overweight or obese people could cut the number of new asthma cases in the United States by 250,000 per year.

In children, where the incidence of asthma is five times higher than in adults, the researchers suggested that even small weight reductions could have a big impact in reducing the number of new asthma diagnoses.

Sutherland said the study gives another reason to develop effective treatments for excess weight, which can cause diabetes, high blood pressure and certain cancers.

The researchers looked at seven studies on severe asthma involving 333,102 patients.

People in the studies either had a doctor's diagnosis of asthma or were taking asthma medication.

They were considered normal weight if their body mass index, a measure of weight in kilograms divided by height in meters was below 25.

People with a BMI measurement of 25 to 29.9 were considered overweight and people with a BMI of 30 or above were considered obese.

The researchers said that obesity has been known to cause impairments in lung function, even among people who do not have asthma.

As a result, some of the overweight and obese patients who said they had asthma may instead have been suffering from reduced lung volume and chest wall restriction associated with their weight, Sutherland said.